Radiotherapy system, irradiation control device, image processing device, processing device, irradiation control method, image processing method, processing method, program, and recording medium

Abstract

To provide a radiotherapy system capable of accurately irradiating a treatment object region with radiation beams even when a treatment object region such as a tumor changes periodically with the respiration of a subject.SOLUTION: In an irradiation control device 26 and an irradiation control method of a radiotherapy system 10, a normalization correlation coefficient with a DRR image is calculated for each of a plurality of shift images generated by shifting a transparent image in a craniocaudal direction of a subject 12. A shift amount of a shift image whose normalization correlation coefficient becomes maximum of a plurality of calculated normalization correlation coefficients is determined as a respiratory positional deviation amount (positional deviation amount) of a diaphragm of the subject 12 in the transparent image with respect to the position of the diaphragm of the subject 12 in the DRR image.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a radiotherapy system, an irradiation control device, an image processing device, a processing method, an irradiation control method, an image processing method, a processing method, a program, and a storage medium. [Background technology]

[0002] Conventionally, there has been known a radiation therapy system that performs radiation therapy on a tumor by irradiating a radiation beam to a treatment target site (e.g., a tumor) in a subject such as a human body (see, for example, Patent Document 1). The position of a tumor often changes periodically with the breathing of the human body. For example, a lung tumor undergoes a periodic positional change of more than 2 cm to 3 cm with the breathing of the human body. For this reason, when performing radiation therapy by irradiating a tumor with a radiation beam, it is necessary to take into consideration the periodic positional change of the tumor associated with the breathing of the human body.

[0003] In order to deal with such periodic positional changes of a tumor due to respiration of the human body, a respiratory synchronous irradiation method is known in which a radiation beam is irradiated to a tumor in synchronization with respiration. In the respiratory synchronous irradiation method, a radiation beam is irradiated to a tumor while the human body's respiration is temporarily stopped. Alternatively, a change in the skin surface of the human body due to respiration is detected, and irradiation of the radiation beam is turned on or off according to the change. When detecting the change in the skin surface of the human body, for example, a strain gauge is attached to the skin surface of the human body. Thereby, the change in the skin surface due to respiration is detected as a pressure change of the strain gauge, and the respiratory phase is detected based on the detected pressure change. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2004-283513 A Summary of the Invention [Problem to be solved by the invention]

[0005] However, in the method of irradiating a tumor with a radiation beam while the breathing of the human body is temporarily stopped, the position of the tumor may not remain stable due to individual differences in the subject. In addition, when a strain gauge is used, the detection characteristics of the pressure corresponding to the variation of the skin surface change depending on the state of attachment of the strain gauge to the skin surface of the human body. As a result, it may be difficult to stably detect the respiratory phase. Therefore, it is desired to be able to irradiate a radiation beam to a treatment target site such as a tumor with high accuracy even when the treatment target site periodically varies with the breathing of the subject.

[0006] An object of the present invention is to solve the above-mentioned problems. [Means for solving the problem]

[0007] A first aspect of the present invention is a radiation therapy system comprising: a treatment planning device which draws up a treatment plan for radiation therapy for a subject; a positioning unit on which the subject is placed; a fluoroscopic image generating device which generates a fluoroscopic image of the subject when the subject is placed on the positioning unit so as to be located on an axis line of the positioning unit; a radiation irradiator having a radiation beam source which irradiates a radiation beam towards the subject when the subject is placed on the positioning unit so as to be located on the axis line; a rotation mechanism which can rotate the positioning unit around the axis line; and an irradiation control device which controls the radiation irradiator based on the treatment plan and the fluoroscopic images to irradiate the radiation beam towards the subject placed on the positioning unit, wherein the irradiation control device comprises a fluoroscopic image acquiring unit which acquires the fluoroscopic images streamed out from the fluoroscopic image generating device and acquires from the rotation mechanism a rotation angle of the positioning unit when the fluoroscopic image generating device generated the fluoroscopic image; a treatment plan acquisition unit that acquires from the treatment planning device the treatment plan including an isocenter coordinate for acquiring the treatment plan, a DRR image generation unit that generates a DRR image of the subject for each predetermined angle around the axis based on the CT image and the isocenter coordinate acquired by the treatment plan acquisition unit, a positional deviation amount calculation unit that calculates a positional deviation amount, which is a positional deviation amount of the respiratory position of the subject's diaphragm in the fluoroscopic image when the position of the subject's diaphragm in the DRR image is used as a reference, by using the fluoroscopic image and the DRR image at the same rotation angle, and a positional deviation amount calculation unit that calculates a positional deviation amount of the respiratory position of the subject's diaphragm in the fluoroscopic image when the position of the subject's diaphragm in the DRR image is used as a reference, and and a permission determination unit that permits irradiation of the radiation beam from the radiation beam source to the subject when the detected value is equal to or less than a predetermined value, wherein the positional deviation calculation unit generates a plurality of shifted images by shifting the fluoroscopic image in a cranial-caudal direction of the subject at predetermined increments within a predetermined range, calculates a normalized correlation coefficient with the DRR image for each of the generated shifted images, and determines, as the positional deviation amount, a shift amount in the cranial-caudal direction with respect to the fluoroscopic image of a shifted image having a maximum normalized correlation coefficient among the calculated normalized correlation coefficients.

[0008] A second aspect of the present invention includes a treatment planning apparatus that creates a treatment plan for radiation therapy for a subject, a gantry, a positioning unit capable of positioning the subject on an axis of the gantry, a fluoroscopic image generating device that is disposed on the gantry and generates a fluoroscopic image of the subject when the subject is positioned on the axis by the positioning unit, a radiation irradiating device that has a radiation beam source disposed on the gantry and irradiates a radiation beam from the radiation beam source towards the subject when the subject is positioned on the axis by the positioning unit, and a fluoroscopic image generating device. and an irradiation control device that controls the radiation irradiator based on the treatment plan and the fluoroscopic images to irradiate the radiation beam towards the subject placed in the positioning unit, wherein the irradiation control device includes a fluoroscopic image acquisition unit that acquires the fluoroscopic images streamed out from the fluoroscopic image generation device and acquires from the rotation mechanism a rotation angle of the fluoroscopic image generation device when the fluoroscopic image generation device generated the fluoroscopic image, and a treatment plan acquisition unit that acquires from the treatment planning device the treatment plan including a CT image in a specific respiratory phase and an isocenter coordinate for specifying an irradiation position of the radiation beam on the subject in the specific respiratory phase; a DRR image generation unit that generates a DRR image of the subject for each predetermined angle around the axis based on the CT image and the isocenter coordinate acquired by the treatment plan acquisition unit; and a fluoroscopic image generation unit that generates a fluoroscopic image of the subject for each predetermined angle around the axis using the fluoroscopic image and the DRR image at the same rotation angle when the position of the diaphragm of the subject in the DRR image is used as a reference. and an authorization determination unit that, when the amount of positional shift is equal to or less than a predetermined value, authorizes irradiation of the radiation beam from the radiation beam source to the subject, wherein the positional shift calculation unit generates a plurality of shifted images by shifting the fluoroscopic image in a cranial-caudal direction of the subject by a predetermined interval within a predetermined range, calculates a normalized correlation coefficient between the DRR image and each of the generated shifted images, and among the calculated normalized correlation coefficients,The shift amount in the cranio-caudal direction of the shifted image that maximizes the normalized correlation coefficient with respect to the perspective image is determined as the positional deviation amount.

[0009] A third aspect of the present invention is a radiation therapy system comprising: a treatment planning device which prepares a treatment plan for radiation therapy on a subject in a specific respiratory phase; a radiation irradiation device which irradiates a radiation beam to the subject based on the treatment plan; a fluoroscopic image generation device which generates a fluoroscopic image of the subject; and an image processing device which performs a predetermined image processing on the fluoroscopic image based on the treatment plan, wherein the treatment plan includes diaphragm information which is three-dimensional information of the diaphragm of the subject in the specific respiratory phase, and the image processing device comprises a projection image generation unit which uses the diaphragm information to generate a projection image which is an image obtained by projecting the diaphragm onto a projection surface of the fluoroscopic image, a contour line extraction unit which extracts a contour line of the diaphragm from the projection image, and a display processing unit which superimposes and displays the contour line on the fluoroscopic image.

[0010] A fourth aspect of the present invention includes a treatment planning device that creates a treatment plan for radiation therapy for a subject in a specific respiratory phase, a positioning unit on which the subject is positioned, a fluoroscopic image generating device that generates a fluoroscopic image of the subject when the subject is positioned on the positioning unit so as to be located on an axis line of the positioning unit, a radiation irradiation device having a radiation beam source that irradiates a radiation beam towards the subject based on the treatment plan when the subject is positioned on the positioning unit so as to be located on the axis line, and a radiation irradiation device that performs predetermined image processing on the fluoroscopic image based on the treatment plan. a rotation mechanism capable of rotating the placement unit around the axis; and an irradiation control device that controls the radiation irradiation device based on the treatment plan and the fluoroscopic image to irradiate the radiation beam toward the subject placed on the placement unit, wherein the treatment plan includes diaphragm information that is three-dimensional information of the diaphragm of the subject in the specific respiratory phase, and the image processing device includes a projection image generation unit that uses the diaphragm information to generate a projection image that is an image obtained by projecting the diaphragm onto a projection plane of the fluoroscopic image, and a projection image generation unit that generates a projection image based on the projection image information. the irradiation control device comprises a contour extraction unit which extracts a contour of the diaphragm from the fluoroscopic image and a display processing unit which superimposes and displays the contour on the fluoroscopic image, the irradiation control device comprising: a fluoroscopic image acquisition unit which executes a predetermined control process after processing by the image processing device, acquires the fluoroscopic image streamed out from the fluoroscopic image generating device, and acquires from the rotation mechanism a rotation angle of the placement unit when the fluoroscopic image generating device generated the fluoroscopic image; a treatment plan acquisition unit that acquires the treatment plan including the isocenter coordinates from the treatment planning device; a DRR image generation unit that generates a DRR image of the subject for each predetermined angle around the axis based on the CT images and the isocenter coordinates acquired by the treatment plan acquisition unit; a positional deviation calculation unit that calculates a positional deviation amount, which is a positional deviation amount of the respiratory position of the subject's diaphragm in the fluoroscopic image when the position of the subject's diaphragm in the DRR image is used as a reference, using the fluoroscopic image and the DRR image at the same rotation angle; andand a permission determination unit that permits irradiation of the radiation beam from the radiation beam source to the subject, wherein the positional deviation calculation unit generates a plurality of shifted images by shifting the fluoroscopic image in a cranial-caudal direction of the subject at a predetermined interval within a predetermined range, calculates a normalized correlation coefficient with the DRR image for each of the generated shifted images, and determines, as the positional deviation amount, a shift amount in the cranial-caudal direction with respect to the fluoroscopic image of a shifted image having a maximum normalized correlation coefficient among the calculated normalized correlation coefficients.

[0011] A fifth aspect of the present invention is a radiation therapy system comprising: a treatment planning device that formulates a treatment plan for radiation therapy for a subject in a specific respiratory phase; a gantry; a positioning unit capable of positioning the subject on an axis of the gantry; a fluoroscopic image generating device that is positioned on the gantry and generates a fluoroscopic image of the subject when the subject is positioned on the axis at the positioning unit; a radiation irradiating device having a radiation beam source positioned on the gantry and causing the radiation beam to be irradiated from the radiation beam source to the subject based on the treatment plan when the subject is positioned on the axis at the positioning unit; an image processing device that performs predetermined image processing on the fluoroscopic image based on the treatment plan; a rotation mechanism that is capable of rotating the fluoroscopic image generating device and the radiation beam source around the axis; and an irradiation control device that controls the radiation irradiating device based on the treatment plan and the fluoroscopic image to irradiate the radiation beam to the subject positioned in the positioning unit, wherein the treatment plan includes diaphragm information that is three-dimensional information of the diaphragm of the subject in the specific respiratory phase. the image processing device includes a projection image generating unit that generates a projection image obtained by projecting the diaphragm onto a projection surface of the perspective image using the diaphragm information, a contour line extracting unit that extracts a contour line of the diaphragm from the projection image, and a display processing unit that displays the contour line superimposed on the perspective image, and the irradiation control device executes a predetermined control process after processing by the image processing device, acquires the perspective image streamed from the perspective image generating device, and detects a rotation angle of the perspective image generating device when the perspective image generating device generates the perspective image. a treatment plan acquisition unit that acquires from the treatment planning device the treatment plan including a CT image of the subject at a specific respiratory phase and an isocenter coordinate for specifying an irradiation position of the radiation beam on the subject at the specific respiratory phase; a DRR image generation unit that generates a DRR image of the subject at each predetermined angle around the axis based on the CT image and the isocenter coordinate acquired by the treatment plan acquisition unit; andand a permission determination unit which permits irradiation of the radiation beam from the radiation beam source to the subject when the amount of positional displacement is equal to or less than a predetermined value, wherein the positional displacement calculation unit generates a plurality of shifted images by shifting the fluoroscopic image in a cranial-caudal direction of the subject by a predetermined interval within a predetermined range, calculates a normalized correlation coefficient with the DRR image for each of the generated shifted images, and determines, as the positional displacement, a shift amount in the cranial-caudal direction relative to the fluoroscopic image of a shifted image having a maximum normalized correlation coefficient among the calculated normalized correlation coefficients.

[0012] A sixth aspect of the present invention is an irradiation control device that controls irradiation of a radiation beam from a radiation beam source of a radiation irradiation device to a subject based on a treatment plan for radiation therapy for the subject and a fluoroscopic image of the subject, wherein the subject is placed on a positioning unit, the fluoroscopic image is generated by a fluoroscopic image generating device when the subject is placed on the positioning unit so as to be located on an axis line of the positioning unit, and the positioning unit is rotatable about the axis line by a rotation mechanism, and the irradiation control device includes a fluoroscopic image acquiring unit that acquires the fluoroscopic image streamed out from the fluoroscopic image generating device and acquires from the rotation mechanism a rotation angle of the positioning unit when the fluoroscopic image generating device generated the fluoroscopic image, a treatment plan acquiring unit that acquires from a treatment planning device the treatment plan including a CT image of the subject in a specific respiratory phase and an isocenter coordinate for specifying an irradiation position of the radiation beam of the subject in the specific respiratory phase, and the positional deviation amount calculation unit calculates a positional deviation amount, which is a positional deviation amount of a respiratory position of the subject's diaphragm in the fluoroscopic image when the position of the subject's diaphragm in the DRR image is used as a reference, using the fluoroscopic image and the DRR image at the same rotation angle; and an authorization determination unit that permits irradiation of the radiation beam from the radiation beam source to the subject when the positional deviation amount is equal to or less than a predetermined value, wherein the positional deviation amount calculation unit generates a plurality of shifted images by shifting the fluoroscopic image in a cranio-caudal direction of the subject by a predetermined increment within a predetermined range, calculates a normalized correlation coefficient with the DRR image for each of the generated shifted images, and determines a shift amount in the cranio-caudal direction relative to the fluoroscopic image of a shifted image having a maximum normalized correlation coefficient among the calculated normalized correlation coefficients as the positional deviation amount.

[0013] A seventh aspect of the present invention is an irradiation control device that controls irradiation of a radiation beam from a radiation beam source of a radiation irradiating device to a subject based on a treatment plan for radiation therapy for the subject and a fluoroscopic image of the subject, wherein the subject is placed on an axis of a gantry by a positioning unit, and the fluoroscopic image is generated by a fluoroscopic image generating device placed on the gantry when the subject is placed on the axis by the positioning unit, the radiation beam source is placed on the gantry and irradiates the radiation beam towards the subject when the subject is placed on the axis by the positioning unit, the fluoroscopic image generating device and the radiation beam source are rotatable around the axis by a rotation mechanism, and the irradiation control device includes a fluoroscopic image acquiring unit that acquires the fluoroscopic images streamed out from the fluoroscopic image generating device and acquires from the rotation mechanism a rotation angle of the fluoroscopic image generating device when the fluoroscopic image was generated by the fluoroscopic image generating device, and an eye for identifying a CT image of the subject in a specific respiratory phase and an irradiation position of the radiation beam of the subject in the specific respiratory phase. a treatment plan acquisition unit that acquires the treatment plan including the isocenter coordinates from a treatment planning device; a DRR image generation unit that generates a DRR image of the subject for each predetermined angle around the axis based on the CT images and the isocenter coordinates acquired by the treatment plan acquisition unit; a positional deviation calculation unit that calculates a positional deviation amount, which is a positional deviation amount of the respiratory position of the subject's diaphragm in the fluoroscopic image when the position of the subject's diaphragm in the DRR image is used as a reference, using the fluoroscopic image and the DRR image at the same rotation angle; and and a permission determination unit that permits irradiation of the radiation beam from the radiation beam source to the subject when the positional deviation is below the predetermined value, and the positional deviation calculation unit generates a plurality of shifted images by shifting the fluoroscopic image in a cranial-caudal direction of the subject at predetermined intervals within a predetermined range, calculates a normalized correlation coefficient with the DRR image for each of the generated shifted images, and determines, as the positional deviation amount, a shift amount in the cranial-caudal direction with respect to the fluoroscopic image of a shifted image having a maximum normalized correlation coefficient among the calculated normalized correlation coefficients.

[0014] An eighth aspect of the present invention is an image processing device that performs predetermined image processing on a fluoroscopic image of a subject generated by a fluoroscopic image generating device based on a treatment plan for radiation therapy for the subject in a specific respiratory phase, the treatment plan including diaphragm information that is three-dimensional information of the diaphragm of the subject in the specific respiratory phase, and the image processing device has a projection image generating unit that uses the diaphragm information to generate a projection image that is an image of the diaphragm projected onto a projection surface of the fluoroscopic image, a contour line extraction unit that extracts a contour line of the diaphragm from the projection image, and a display processing unit that superimposes and displays the contour line on the fluoroscopic image.

[0015] A ninth aspect of the present invention is a processing device that performs predetermined image processing on a fluoroscopic image of a subject generated by a fluoroscopic image generating device based on a treatment plan of radiation therapy for the subject in a specific respiratory phase, and then controls irradiation of a radiation beam from a radiation beam source of a radiation irradiation device to the subject based on the treatment plan and the fluoroscopic image, wherein the treatment plan includes diaphragm information that is three-dimensional information of the diaphragm of the subject in the specific respiratory phase, and the processing device has an image processing device and an irradiation control device, a projection image generating unit that generates a projection image, which is an image obtained by projecting the diaphragm onto a projection surface of the perspective image, using membrane information; a contour line extracting unit that extracts a contour line of the diaphragm from the projection image; and a display processing unit that displays the contour line superimposed on the perspective image, wherein the subject is placed on a placement unit, and the perspective image is generated by a perspective image generating device when the subject is placed on the placement unit so as to be located on an axis line of the placement unit, and the placement unit is rotatable around the axis line by a rotation mechanism, and the irradiation control device is a control unit of the image processing device. a fluoroscopic image acquisition unit that executes a predetermined control process after the processing, acquires the fluoroscopic image streamed out from the fluoroscopic image generation device, and acquires from the rotation mechanism the rotation angle of the placement unit when the fluoroscopic image generation device generated the fluoroscopic image; a treatment plan acquisition unit that acquires from a treatment planning device the treatment plan including a CT image of the subject in a specific respiratory phase and an isocenter coordinate for specifying an irradiation position of the subject with the radiation beam in the specific respiratory phase; a DRR image generating unit that generates a DRR image of the subject for each predetermined angle around the axis based on the socentric coordinates; a misalignment amount calculating unit that calculates a misalignment amount, which is an amount of misalignment of a respiratory position of the subject's diaphragm in the fluoroscopic image when the position of the subject's diaphragm in the DRR image is used as a reference, using the fluoroscopic image and the DRR image at the same rotation angle; and a permission determining unit that permits irradiation of the radiation beam from the radiation beam source to the subject when the misalignment amount is equal to or less than a predetermined value,A plurality of shifted images are generated by shifting the fluoroscopic image in a cranio-caudal direction of the subject within a predetermined range at a predetermined interval, a normalized correlation coefficient between each of the generated shifted images and the DRR image is calculated, and a shift amount in the cranio-caudal direction of the shifted image with the maximum normalized correlation coefficient among the calculated normalized correlation coefficients is determined as the positional deviation amount.

[0016] A tenth aspect of the present invention is a processing device that performs predetermined image processing on a fluoroscopic image of a subject generated by a fluoroscopic image generating device based on a treatment plan for radiation therapy for a subject in a specific respiratory phase, and then controls irradiation of a radiation beam from a radiation beam source of a radiation irradiation device to the subject based on the treatment plan and the fluoroscopic image, wherein the treatment plan includes diaphragm information that is three-dimensional information of the diaphragm of the subject in the specific respiratory phase, and the processing device has an image processing device and an irradiation control device, and the image processing device performs a predetermined image processing on a fluoroscopic image of the subject generated by a fluoroscopic image generating device based on the treatment plan and the fluoroscopic image, a projection image generating unit that generates a projection image, which is an image obtained by projecting the diaphragm onto a projection surface of the perspective image, a contour line extracting unit that extracts a contour line of the diaphragm from the projection image, and a display processing unit that displays the contour line in a superimposed manner on the perspective image, wherein the subject is placed on an axis of a gantry by a placement unit, and the perspective image is generated by a perspective image generating device placed on the gantry when the subject is placed on the axis by the placement unit, and the radiation beam source is placed on the gantry, and when the subject is placed on the axis by the placement unit, the irradiation control device executes a predetermined control process after processing by the image processing device, acquires the fluoroscopic image streamed out from the fluoroscopic image generating device, and acquires from the rotation mechanism a rotation angle of the fluoroscopic image generating device when the fluoroscopic image is generated by the fluoroscopic image generating device; a treatment plan acquisition unit that acquires the treatment plan including an isocenter coordinate for specifying an irradiation position of a radiation beam from a treatment planning device; a DRR image generation unit that generates a DRR image of the subject for each predetermined angle around the axis based on the CT image and the isocenter coordinate acquired by the treatment plan acquisition unit; and a positional deviation calculation unit that calculates a positional deviation, which is a positional deviation of the respiratory position of the subject's diaphragm in the fluoroscopic image when the position of the subject's diaphragm in the DRR image is used as a reference, using the fluoroscopic image and the DRR image at the same rotation angle.and a permission determination unit that permits irradiation of the radiation beam from the radiation beam source to the subject when the amount of positional deviation is equal to or less than a predetermined value, wherein the positional deviation calculation unit generates a plurality of shifted images by shifting the fluoroscopic image in a cranial-caudal direction of the subject at predetermined intervals within a predetermined range, calculates a normalized correlation coefficient with the DRR image for each of the generated shifted images, and determines, as the amount of positional deviation, a shift amount in the cranial-caudal direction with respect to the fluoroscopic image of a shifted image having a maximum normalized correlation coefficient among the calculated normalized correlation coefficients.

[0017] An eleventh aspect of the present invention is an irradiation control method for controlling irradiation of a radiation beam from a radiation beam source of a radiation irradiation device to a subject, based on a treatment plan for radiation therapy for the subject and a fluoroscopic image of the subject, wherein the subject is placed on a positioning unit, the fluoroscopic image is generated by a fluoroscopic image generating device when the subject is placed on the positioning unit so as to be located on an axis line of the positioning unit, and the positioning unit is rotatable around the axis line by a rotation mechanism, and the irradiation control method includes a treatment plan acquisition step of acquiring the treatment plan including a CT image of the subject in a specific respiratory phase and an isocenter coordinate for specifying an irradiation position of the radiation beam of the subject in the specific respiratory phase, a DRR image generation step of generating a DRR image of the subject for each predetermined angle around the axis line based on the acquired CT image and the isocenter coordinate, and a fluoroscopic image generation step of acquiring the fluoroscopic image streamed out from the fluoroscopic image generating device and generating the fluoroscopic image. the positional deviation amount calculation step of calculating, using the fluoroscopic image and the DRR image at the same rotation angle, a positional deviation amount which is a deviation amount of a respiratory position of the subject's diaphragm in the fluoroscopic image when the position of the subject's diaphragm in the DRR image is used as a reference; and an irradiation permission step of permitting irradiation of the radiation beam from the radiation beam source to the subject when the positional deviation amount is equal to or less than a predetermined value, wherein the positional deviation amount calculation step generates a plurality of shifted images by shifting the fluoroscopic image in a cranial-caudal direction of the subject by a predetermined increment within a predetermined range, calculates a normalized correlation coefficient with the DRR image for each of the generated shifted images, and determines, as the positional deviation amount, a shift amount in the cranial-caudal direction relative to the fluoroscopic image of a shifted image having a maximum normalized correlation coefficient among the calculated normalized correlation coefficients.

[0018] A twelfth aspect of the present invention is an irradiation control method for controlling irradiation of a radiation beam from a radiation beam source of a radiation irradiation apparatus to a subject, based on a treatment plan for radiation therapy for the subject and a fluoroscopic image of the subject, wherein the subject is placed on an axis of a gantry by a positioning unit, the fluoroscopic image is generated by a fluoroscopic image generating device placed on the gantry when the subject is placed on the axis by the positioning unit, the radiation beam source is placed on the gantry and irradiates the radiation beam toward the subject when the subject is placed on the axis by the positioning unit, and the fluoroscopic image generating device and the radiation beam source are rotatable around the axis by a rotation mechanism, and the irradiation control method includes a treatment plan acquisition step of acquiring the treatment plan including a CT image of the subject in a specific respiratory phase and an isocenter coordinate for specifying an irradiation position of the radiation beam of the subject in the specific respiratory phase, and a DRR image generation step of generating a DRR image of the subject for each predetermined angle around the axis based on the acquired CT image and the isocenter coordinate. a fluoroscopic image acquiring step of acquiring the fluoroscopic images streamed out from the fluoroscopic image generating device and acquiring from the rotation mechanism a rotation angle of the fluoroscopic image generating device when the fluoroscopic image generating device generated the fluoroscopic image; a positional deviation calculation step of calculating a positional deviation amount, which is a positional deviation amount of the respiratory position of the diaphragm of the subject in the fluoroscopic image when the position of the diaphragm of the subject in the DRR image is used as a reference, using the fluoroscopic image and the DRR image at the same rotation angle; and and an irradiation permission step of permitting irradiation of the radiation beam from the radiation beam source to the subject, wherein the positional deviation calculation step generates a plurality of shifted images by shifting the fluoroscopic image in a cranial-caudal direction of the subject within a predetermined range at predetermined intervals, calculates a normalized correlation coefficient with the DRR image for each of the generated shifted images, and determines, as the positional deviation amount, a shift amount in the cranial-caudal direction with respect to the fluoroscopic image of the shifted image having a maximum normalized correlation coefficient among the calculated normalized correlation coefficients.

[0019] A thirteenth aspect of the present invention is an image processing method for performing predetermined image processing on a fluoroscopic image of a subject generated by a fluoroscopic image generating device based on a treatment plan for radiation therapy for the subject in a specific respiratory phase, the treatment plan including diaphragm information which is three-dimensional information of the diaphragm of the subject in the specific respiratory phase, the image processing method including a projection image generating step of generating a projection image which is an image of the diaphragm projected onto a projection surface of the fluoroscopic image using the diaphragm information, a contour extraction step of extracting a contour of the diaphragm from the projection image, and a display processing step of superimposing and displaying the contour on the fluoroscopic image.

[0020] A fourteenth aspect of the present invention is a processing method for performing predetermined image processing on a fluoroscopic image of a subject generated by a fluoroscopic image generating device based on a treatment plan for radiation therapy for the subject in a specific respiratory phase, and then controlling irradiation of a radiation beam from a radiation beam source of a radiation irradiation device to the subject based on the treatment plan and the fluoroscopic image, wherein the treatment plan includes diaphragm information which is three-dimensional information of the diaphragm of the subject in the specific respiratory phase, the subject is placed on a positioning unit, and the fluoroscopic image is generated based on the positioning unit so that the subject is positioned on an axis line of the positioning unit. a projection image generating step of generating a projection image by using the diaphragm information, the projection image being an image of the diaphragm projected onto a projection surface of the fluoroscopic image, a contour line extracting step of extracting a contour line of the diaphragm from the projection image, a display processing step of superimposing and displaying the contour line on the fluoroscopic image, and a CT image of the subject in the specific respiratory phase and a CT image of the subject in the specific respiratory phase after the display processing step are performed. a treatment plan acquisition step of acquiring the treatment plan including an isocenter coordinate for specifying an irradiation position of a radiation beam; a DRR image generation step of generating a DRR image of the subject for each predetermined angle around the axis based on the acquired CT images and the isocenter coordinate; a fluoroscopic image acquisition step of acquiring the fluoroscopic images streamed out from the fluoroscopic image generation device and acquiring from the rotation mechanism a rotation angle of the placement unit when the fluoroscopic image generation device generated the fluoroscopic images; and an irradiation permission step of permitting irradiation of the radiation beam from the radiation beam source to the subject when the positional deviation is equal to or less than a predetermined value. In the positional deviation calculation step, a plurality of shifted images are generated by shifting the fluoroscopic image in a cranial-caudal direction of the subject by a predetermined interval within a predetermined range, and for each of the generated shifted images,A normalized correlation coefficient with the DRR image is calculated, and the shift amount in the cranio-caudal direction of the shift image with the maximum normalized correlation coefficient among the calculated normalized correlation coefficients is determined as the positional deviation amount.

[0021] A fifteenth aspect of the present invention is a processing method for performing predetermined image processing on a fluoroscopic image of a subject generated by a fluoroscopic image generating device based on a treatment plan for radiation therapy for a subject in a specific respiratory phase, and then controlling irradiation of a radiation beam from a radiation beam source of a radiation irradiation device to the subject based on the treatment plan and the fluoroscopic image, wherein the treatment plan includes diaphragm information which is three-dimensional information of the diaphragm of the subject in the specific respiratory phase, the subject is placed on an axis of a gantry by a positioning unit, and the fluoroscopic image is generated by the positioning unit when the subject is positioned on the axis. a fluoroscopic image generating device arranged on the gantry when the subject is arranged on the axis line, the radiation beam source is arranged on the gantry, and when the subject is arranged on the axis line by the arrangement unit, the radiation beam is irradiated toward the subject, and the fluoroscopic image generating device and the radiation beam source are rotatable around the axis line by a rotation mechanism, and the processing method includes a projection image generating step of generating a projection image, which is an image obtained by projecting the diaphragm onto a projection surface of the fluoroscopic image, using the diaphragm information, and a circular extraction step of extracting a contour line of the diaphragm from the projection image. a contour extraction step, a display processing step of superimposing and displaying the contour on the fluoroscopic image, a treatment plan acquisition step of acquiring the treatment plan including a CT image in the specific respiratory phase and an isocenter coordinate for specifying an irradiation position of the radiation beam on the subject in the specific respiratory phase after the display processing step is executed, a DRR image generation step of generating DRR images of the subject for each predetermined angle around the axis based on the acquired CT image and the isocenter coordinate, and a fluoroscopic image acquiring step of acquiring from the rotation mechanism a rotation angle of the fluoroscopic image generating device when the fluoroscopic image generating device generated the fluoroscopic image; a positional deviation calculating step of calculating a positional deviation amount, which is a positional deviation amount of a respiratory position of the diaphragm of the subject in the fluoroscopic image when the position of the diaphragm of the subject in the DRR image is used as a reference, using the fluoroscopic image and the DRR image at the same rotation angle; and an irradiation permitting step of permitting irradiation of the radiation beam from the radiation beam source to the subject when the positional deviation amount is equal to or less than a predetermined value.In the positional deviation amount calculation step, a plurality of shifted images are generated by shifting the fluoroscopic image in a cranial-caudal direction of the subject within a predetermined range at a predetermined interval, a normalized correlation coefficient between each of the generated shifted images and the DRR image is calculated, and a shift amount in the cranial-caudal direction with respect to the fluoroscopic image of a shifted image having a maximum normalized correlation coefficient among the calculated normalized correlation coefficients is determined as the positional deviation amount.

[0022] A 16th aspect of the present invention is a program for causing a computer to execute at least one of the irradiation control method of the 11th aspect or the 12th aspect, the image processing method of the 13th aspect, and the processing method of the 14th aspect or the 15th aspect.

[0023] A seventeenth aspect of the present invention is a storage medium storing the program according to the sixteenth aspect. Effect of the Invention

[0024] According to the first, second, sixth, seventh, eleventh and twelfth aspects of the present invention, a fluoroscopic image and a DRR image having the same rotation angle are used to calculate a respiratory positional shift (positional shift) of the diaphragm in the fluoroscopic image (shift image) relative to the position of the diaphragm of the subject in the DRR image. If the calculated positional shift is equal to or less than a predetermined value, irradiation of the radiation beam from the radiation beam source to the subject is permitted. As a result, even if the position of a treatment target site such as a tumor, which is the irradiation position of the radiation beam, periodically fluctuates due to the subject's breathing, the subject is made to hold his / her breath so that the positional shift of the diaphragm is equal to or less than a predetermined value, so that the treatment target site can be accurately irradiated with the radiation beam.

[0025] According to the third, eighth and thirteenth aspects of the present invention, the diaphragm information of the subject included in the treatment plan is projected onto a projection surface to generate a projection image, the contour of the diaphragm is extracted from the projection image, and the contour is superimposed on the perspective image of the subject. The user checks the image in which the contour at the time of the treatment plan is superimposed on the perspective image. This allows the user to easily grasp whether the position of the treatment target site, such as a tumor, which is the irradiation position of the radiation beam, has shifted while the subject is holding his / her breath, using the diaphragm which is easily visible. In other words, the user can easily grasp whether the amount of positional shift of the diaphragm which is easily visible is within an allowable range. Therefore, if the position of the diaphragm deviates from the target at the time of the treatment plan, the irradiation of the radiation beam to the subject can be interrupted. As a result, it becomes possible to irradiate the radiation beam to the treatment target site with high accuracy.

[0026] Furthermore, according to the fourth, fifth, ninth, tenth, fourteenth and fifteenth aspects of the present invention, first, radiation therapy is performed on the subject based on the above image processing, and if there is no particular problem, radiation therapy is then performed on the subject based on the above irradiation control processing. This makes it possible to perform radiation therapy on the subject with high accuracy. [Brief description of the drawings]

[0027] [Figure 1] FIG. 1 is a configuration diagram of a radiation therapy system according to the first embodiment. [Diagram 2] FIG. 2 is a configuration diagram of the radiation therapy system according to the first embodiment. [Diagram 3] FIG. 3 is a block diagram of the radiation therapy system of FIGS. [Figure 4] FIG. 4 is a flowchart showing the operation of the radiation therapy system of FIGS. [Diagram 5] FIG. 5 is a flowchart showing the details of step S4 in FIG. [Figure 6] FIG. 6 is a flow chart showing a part (first embodiment) of the process of step S11 in FIG. [Figure 7] FIG. 7 is a flow chart showing a part (second embodiment) of the process of step S11 in FIG. [Figure 8] FIG. 8 is a flow chart showing a part (third embodiment) of the process of step S11 in FIG. [Figure 9] FIG. 9 is a diagram showing an example of a DRR image. [Figure 10] FIG. 10 is a diagram showing an example of a perspective image. [Figure 11] FIG. 11 is a diagram illustrating an example of the first partial image region of the DRR image. [Figure 12] FIG. 12 is a diagram showing an example of the second partial image region of the perspective image. [Figure 13] FIG. 13 is a diagram showing an example of a screen display. [Figure 14] FIG. 14 is a diagram showing an example of a screen display in which the contrast of each of the DRR image and the fluoroscopic image is improved. [Figure 15] FIG. 15 is a diagram showing an example of a perspective image. [Figure 16] FIG. 16 shows a perspective image with improved contrast. [Figure 17] FIG. 17 is a configuration diagram showing a second modified example. [Figure 18] FIG. 18 is a configuration diagram of a radiation therapy system according to the second embodiment. [Figure 19] FIG. 19A is a diagram showing a projection image of the diaphragm, and FIG. 19B is a diagram showing the contour line of the diaphragm. [Figure 20] FIG. 20A is a diagram showing a perspective image of a subject, and FIG. 20B is a diagram showing a state in which a contour line is superimposed on the perspective image. [Figure 21] 21A and 21B are diagrams showing a state in which two moving contour lines are superimposed on a perspective image of a subject. [Figure 22] FIG. 22 is a flowchart showing the operation of the radiotherapy system of FIG. [Figure 23] FIG. 23 is a flowchart showing details of the flowchart of FIG. [Figure 24] FIG. 24 is a configuration diagram showing a third modified example. [Diagram 25] FIG. 25 is a configuration diagram showing a fourth modified example. [Figure 26] FIG. 26 is a configuration diagram showing the fifth modified example. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0028] [Configuration of the first embodiment] 1 and 2 are configuration diagrams of a radiation therapy system 10 according to a first embodiment of the present invention.

[0029] A radiation therapy system 10 according to the first embodiment is installed in, for example, a medical institution. The radiation therapy system 10 performs radiation therapy on a subject 12. The subject 12 is a patient's body or the like. The radiation therapy system 10 performs radiation therapy on a treatment target site in the subject 12. The treatment target site is, for example, a tumor. The radiation therapy system 10 performs radiation therapy on the tumor by irradiating the tumor with a radiation beam 14. Note that, examples of the radiation beam 14 include a beam of high-energy X-rays, and a beam of particle rays such as a proton beam or a carbon beam.

[0030] The radiation therapy system 10 includes a CT device 16, a treatment planning device 18, a radiation irradiator 20, a beam control device 22, a fluoroscopic image generating device 24, an irradiation control device 26 (computer), a chair 28 (positioning section), and a drive mechanism 30 (rotation mechanism, first rotation mechanism, second rotation mechanism). The irradiation control device 26, the treatment planning device 18, the fluoroscopic image generating device 24, and the beam control device 22 are configured to be able to communicate bidirectionally.

[0031] The CT device 16 generates a CT image of the inside of the patient at a specific respiratory phase for each patient who is the subject 12. The CT device 16 transmits the generated CT image to the treatment planning device 18. Note that the CT device 16 may be, for example, a CT device for treatment planning equipped with a respiratory sensor. This allows the CT device 16 to capture a CT image of the subject 12 at a specific respiratory phase (for example, while the subject 12 is holding his / her breath and exhaling quietly).

[0032] The treatment planning device 18 creates a treatment plan for radiation therapy for the subject 12. Specifically, the treatment planning device 18 uses the CT images received from the CT device 16 to identify the position of a tumor during a specific breathing motion of the subject 12. The treatment planning device 18 creates a treatment plan including a CT image and isocenter coordinates for identifying a site to be irradiated with the radiation beam 14. The site to be irradiated is the tumor as a site to be treated. The CT image and the isocenter coordinates are three-dimensional information. The CT image is composed of slice images (CT slice images) obtained at predetermined intervals (slice width) in the craniocaudal direction of the subject 12.

[0033] The specific respiratory phase may be a quiet exhalation, a deep exhalation, or a deep inspiration of the subject 12. Quiet exhalation or deep exhalation includes the maximum exhalation of the subject 12. Deep inspiration includes the maximum inspiration of the subject 12. The treatment target area temporarily stops breathing during quiet exhalation, deep exhalation, and deep inspiration. Therefore, it is desirable to have the subject 12 hold his / her breath in a quiet exhalation, deep exhalation, or deep inspiration state. If the treatment target area is irradiated with the radiation beam 14 in such a respiratory phase, radiation therapy can be performed with high accuracy. The subject 12 can also maintain a breath-holding state in a specific phase between quiet exhalation or deep exhalation and deep inspiration.

[0034] The treatment planning device 18 transmits the drawn up treatment plan (CT images, isocenter coordinates) to the irradiation control device 26 as data conforming to the DICOM-RT standard.

[0035] The driving mechanism 30 is provided on a floor surface 32. The floor surface 32 is the floor surface of a medical institution in which the radiation therapy system 10 is provided. The driving mechanism 30 has a driving unit 34 and a rotating table 36. The driving unit 34 is disposed on the floor surface 32. The rotating table 36 is a disk disposed on the upper surface of the driving unit 34. The rotating table 36 is disposed on the upper surface of the driving unit 34 so that an axis 38 passing through the center of the rotating table 36 intersects with the floor surface 32. In Figs. 1 and 2, a case is illustrated in which the axis 38 of the rotating table 36 is perpendicular to the floor surface 32. The driving unit 34 can rotate the rotating table 36 around the axis 38. The driving unit 34 has a rotation angle sensor 40. The rotation angle sensor 40 successively detects the rotation angle of the rotating table 36 and outputs the detection result to the irradiation control device 26. An example of the rotation angle sensor 40 is a rotary encoder.

[0036] The chair 28 is placed on the upper surface of the rotating table 36. The chair 28 is placed on the rotating table 36 coaxially with the axis 38. The subject 12 is seated on the chair 28. The subject 12 is seated on the chair 28 so as to be located on the axis 38. The driving unit 34 rotates the rotating table 36 while the subject 12 is seated on the chair 28. This causes the chair 28 and the subject 12 to rotate around the axis 38. Since the chair 28 also rotates in conjunction with the rotation of the rotating table 36, the rotation angle sensor 40 detects the rotation angle of the rotating table 36 as the rotation angle of the chair 28 and the subject 12.

[0037] The radiation irradiation device 20 is fixed to the floor surface 32 outside the drive mechanism 30. As shown in FIG. 1, the radiation irradiation device 20 has an apparatus body 42 and a radiation beam source 44. The apparatus body 42 is a housing fixed to the floor surface 32. The radiation beam source 44 is provided inside the apparatus body 42. A radiation exit port (irradiation port) 45 is provided in the apparatus body 42 at a position facing the subject 12 seated on the chair 28. The radiation beam source 44 faces the subject 12 seated on the chair 28 through the radiation exit port 45. The radiation beam source 44 can irradiate the radiation beam 14 from the radiation exit port 45 toward the subject 12 seated on the chair 28. Therefore, the radiation beam source 44 can irradiate the radiation beam 14 toward the subject 12 seated on the chair 28 located at an arbitrary rotation angle. Therefore, in the first embodiment, radiation therapy is performed on the subject 12 in a sitting position. 1, a radiation emission port 45 is provided on the side of the apparatus body 42 facing the chair 28. The radiation beam source 44 irradiates the subject 12 with the radiation beam 14 in the horizontal direction from the radiation emission port 45, thereby performing radiation therapy on the tumor in the subject 12.

[0038] The beam control device 22 controls the radiation irradiator 20 and the drive mechanism 30. Specifically, the beam control device 22 controls the radiation irradiator 20 based on a control signal (irradiation permission signal) from the irradiation control device 26. As a result, the radiation beam 14 is irradiated from the radiation beam source 44 towards the subject 12. The beam control device 22 also controls the drive mechanism 30 based on a control signal (e.g., an irradiation permission signal) from the irradiation control device 26. As a result, the turntable 36, the chair 28, and the subject 12 rotate around an axis 38.

[0039] As shown in FIG. 2, the fluoroscopic image generating device 24 is disposed on the floor surface 32 outside the driving mechanism 30 so as to sandwich the driving mechanism 30 and the chair 28. The fluoroscopic image generating device 24 has an X-ray tube 46, a detector 48 (X-ray detector), and a computer 50. Outside the driving mechanism 30, two support members 52, 54 extend upward from the floor surface 32. The two support members 52, 54 face each other with the driving mechanism 30 and the chair 28 in between. As shown in FIG. 1, the device body 42 of the radiation irradiation device 20 is fixed to the floor surface 32 outside the driving mechanism 30. Therefore, as shown in FIG. 2, the two support members 52, 54 are fixed to the floor surface 32 at an angular position (rotation angle) different from that of the radiation irradiation device 20. For example, one of the support members 52 is disposed at an angular position of +90° from the radiation irradiation device 20 around the axis 38. The other support member 54 is disposed at an angular position of −90° from the radiation irradiation device 20 around the axis 38. The X-ray tube 46 is attached to the side surface of one support member 52 facing the chair 28. The detector 48 is attached to the side surface of the other support member 54 facing the chair 28. Thus, the X-ray tube 46 and the detector 48 face each other with the chair 28 in between.

[0040] The X-ray tube 46 irradiates X-rays 56 toward the subject 12 seated on the chair 28 based on a control signal from the beam control device 22. Therefore, the X-ray tube 46 can irradiate the X-rays 56 toward the subject 12 from any rotation angle of the chair 28. The detector 48 detects the X-rays 56 that have passed through the subject 12, thereby generating a fluoroscopic image of the subject 12 at any rotation angle. The computer 50 outputs the fluoroscopic image to the irradiation control device 26.

[0041] As shown in FIG. 3, the irradiation controller 26 includes a processing unit 57, an operation unit 58, a display unit 60, and a memory 62 (storage medium).

[0042] The processing unit 57 may be configured by a processor such as a CPU. That is, the processing unit 57 may be configured by a processing circuit. The processing unit 57 has a treatment plan acquisition unit 64, a fluoroscopic image acquisition unit 66, a DRR image generation unit 68, a positional deviation amount calculation unit 70, an irradiation permission determination unit 72, an irradiation permission signal output unit 74, and a display processing unit 76. The treatment plan acquisition unit 64, the fluoroscopic image acquisition unit 66, the DRR image generation unit 68, the positional deviation amount calculation unit 70, the irradiation permission determination unit 72, the irradiation permission signal output unit 74, and the display processing unit 76 may be realized by the processing unit 57 executing a program stored in the memory 62. Note that at least a part of the treatment plan acquisition unit 64, the fluoroscopic image acquisition unit 66, the DRR image generation unit 68, the positional deviation amount calculation unit 70, the irradiation permission determination unit 72, the irradiation permission signal output unit 74, and the display processing unit 76 may be realized by an integrated circuit such as an ASIC or an FPGA. In addition, at least a portion of the treatment plan acquisition unit 64, the fluoroscopic image acquisition unit 66, the DRR image generation unit 68, the positional deviation calculation unit 70, the irradiation permission determination unit 72, the irradiation permission signal output unit 74, and the display processing unit 76 may be configured by electronic circuits including discrete devices.

[0043] The memory 62 may be composed of a volatile memory (not shown) and a non-volatile memory (not shown). The volatile memory may be, for example, a RAM. The volatile memory is used as a working memory of the processor, and temporarily stores data and the like required for processing or calculation. The non-volatile memory may be, for example, a ROM, a flash memory, and the like. The non-volatile memory is used as a storage memory, and stores programs, tables, maps, and the like. At least a part of the memory 62 may be provided in the above-mentioned processor, integrated circuit, and the like.

[0044] The irradiation controller 26 functions as a controller for controlling the irradiation of the radiation beam 14 from a radiation beam source 44 (see FIG. 1) to the subject 12.

[0045] Specifically, the treatment plan acquisition unit 64 acquires (receives) the treatment plan (CT image, isocenter coordinates) transmitted from the treatment planning device 18.

[0046] The perspective image acquiring unit 66 acquires the perspective images output from the perspective image generating device 24. In addition, the perspective image acquiring unit 66 successively acquires the rotation angle from the rotation angle sensor 40 of the drive mechanism 30.

[0047] The DRR image generating unit 68 generates DRR images of the subject 12 at each predetermined angle around the axis 38 from the CT image and isocenter coordinates included in the treatment plan. Specifically, the DRR image generating unit 68 generates DRR images at each arbitrary angle (predetermined angle) within a range of 0.5° to 5°. The predetermined angle is preferably 1°. The DRR image is a perspective image of the inside of the subject 12 that is simulated and calculated from the CT image for the treatment plan. More specifically, the DRR image generating unit 68 projects a plurality of CT slice images that constitute the CT image onto a virtual projection surface of the perspective image. This generates a DRR image that is a projection image of the CT image. In this case, the DRR image generating unit 68 generates a DRR image using a CT image under breath holding for a specific respiratory phase used in radiation therapy.

[0048] When radiation therapy is being performed on the subject 12, the fluoroscopic image acquisition unit 66 sequentially receives fluoroscopic images in real time from the fluoroscopic image generation device 24. In addition, the fluoroscopic image acquisition unit 66 sequentially receives rotation angles in real time from the rotation angle sensor 40. Therefore, the treatment plan acquisition unit 64 needs to receive CT images and isocenter information before the start of radiation therapy on the subject 12. In addition, the DRR image generation unit 68 needs to generate a DRR image before the start of radiation therapy on the subject 12.

[0049] Incidentally, the position of a tumor in the subject 12 may move several centimeters in the cranial-caudal direction of the subject 12 due to the breathing movement of the subject 12. Furthermore, a fluoroscopic image is a two-dimensional image given as the intensity distribution of radiation that has passed through the subject 12. Therefore, it is often difficult to confirm a relatively small tumor in a fluoroscopic image. Furthermore, the diaphragm is displaced due to the breathing movement of the subject 12. However, the diaphragm is relatively large compared to a tumor. Furthermore, the diaphragm is located between the low-density lungs and the high-density liver. Therefore, the diaphragm is easy to see in a fluoroscopic image.

[0050] The positional deviation amount calculation unit 70 uses the fluoroscopic image and the DRR image at the same rotation angle to calculate the amount of deviation of the respiratory position of the diaphragm of the subject 12 in the fluoroscopic image from the position of the diaphragm when the position of the diaphragm of the subject 12 in the DRR image is used as a reference. That is, the positional deviation amount calculation unit 70 calculates the amount of deviation (positional deviation amount) of the position of the diaphragm in the fluoroscopic image from the position of the diaphragm in the DRR image by comparing the positions of the diaphragm between the fluoroscopic image and the DRR image at the same rotation angle. This makes it possible to determine whether or not a tumor actually exists at the irradiation position of the radiation beam 14 that is predetermined in the treatment plan.

[0051] The positional deviation calculation unit 70 shifts the fluoroscopic image at the same rotation angle in the cranio-caudal direction, for example, within a range of ±2 mm to ±10 mm and at intervals (step widths) within a range of 0.5 mm to 1.5 mm, based on the anatomical shape of the subject 12. This generates a plurality of shifted images.

[0052] That is, the positional deviation calculation unit 70 generates a plurality of shifted images within a predetermined range of ±2 mm to ±10 mm along the cranio-caudal direction based on the anatomical shape of the subject 12 with respect to the original fluoroscopic image. Specifically, the predetermined range is preferably an integer or half-integer value within ±2 mm to ±10 mm. Also, the increment width for shifting the fluoroscopic image is preferably within a range of 0.5 mm to 1.5 mm. Specifically, the increment width is preferably an integer or half-integer value (0.5 mm, 1.0 mm, 1.5 mm) within a range of 0.5 mm to 1.5 mm. Incidentally, within the predetermined range, the positive direction is the head direction of the subject 12 with respect to the original fluoroscopic image. Also, the negative direction is the foot direction of the subject 12 with respect to the original fluoroscopic image.

[0053] The positional deviation amount calculation unit 70 calculates a normalized correlation coefficient between each of the multiple shifted images and the DRR image. The positional deviation amount calculation unit 70 determines the shift amount corresponding to the shifted image with the maximum normalized correlation coefficient as the above-mentioned positional deviation amount. For example, if there is no positional deviation of the diaphragm between the fluoroscopic image and the DRR image, the normalized correlation coefficient is maximum in the shifted image with a shift amount of 0 mm. A specific calculation method of the normalized correlation coefficient will be described later.

[0054] When the amount of positional deviation is equal to or less than a predetermined value, the irradiation permission determination unit 72 permits irradiation of the radiation beam 14 from the radiation beam source 44 to the subject 12. In other words, if the amount of positional deviation is equal to or less than a predetermined value, the position of the tumor in the DRR image and the position of the tumor in the fluoroscopic image generally coincide with each other. In this state, if the radiation beam 14 is irradiated from the radiation beam source 44 toward the subject 12, it becomes possible to perform radiation therapy on the tumor with high accuracy.

[0055] When the irradiation permission determination unit 72 determines that irradiation of the radiation beam 14 is permitted, the irradiation permission signal output unit 74 transmits an irradiation permission signal instructing permission of irradiation of the radiation beam 14 to the beam control device 22. For example, when the irradiation control device 26 and the beam control device 22 are connected via a USB cable, the irradiation permission signal output unit 74 may transmit the irradiation permission signal to the beam control device 22 by USB communication. This ensures that the irradiation permission signal can be transmitted from the irradiation control device 26 to the beam control device 22. The beam control device 22 controls the radiation irradiator 20 only when it receives the irradiation permission signal. As a result, the radiation beam 14 is irradiated from the radiation beam source 44 towards the subject 12.

[0056] The display processing unit 76 performs display processing for displaying various images such as a DRR image and a fluoroscopic image on the display unit 60. The display processing unit 76 performs display processing for displaying images for setting the above-mentioned predetermined range, step size, and predetermined value on the display unit 60. The display unit 60 is a display. The display unit 60 displays the image created by the display processing unit 76 on a screen.

[0057] The operation unit 58 is an operation unit such as a touch panel, a keyboard, a mouse, etc. The user of the radiation therapy system 10 checks the display content of the display unit 60 and operates the operation unit 58. As a result, at least one value of the predetermined range, the step size, and the predetermined value is set or changed.

[0058] [Operation of the first embodiment] Next, the operation (irradiation control method) of the radiation therapy system 10 including the irradiation control device 26 will be described with reference to Figures 4 to 16. In this operation explanation, Figures 1 to 3 will also be referred to as necessary. Here, a case where radiation therapy is performed on a tumor in a subject 12 at a medical institution where the radiation therapy system 10 is installed will be described.

[0059] Prior to the administration of radiation therapy, the CT device 16 generates a CT image of the subject 12 at a specific respiratory phase (e.g., quiet expiration, deep expiration, or deep inspiration of the subject 12). Note that the fluoroscopic image generating device 24 may generate the CT image of the subject 12.

[0060] Next, the treatment planning device 18 acquires a CT image of the subject 12 from the CT device 16 or the fluoroscopic image generating device 24. The treatment planning device 18 uses the acquired CT image to create a treatment plan for the subject 12. Specifically, the treatment planning device 18 determines the position of the tumor in the CT image as a region to be irradiated with the radiation beam 14. Next, the treatment planning device 18 identifies the isocenter coordinates, which are the coordinates of the tumor position (region to be irradiated). As a result, a treatment plan including the CT image and the isocenter coordinates is created.

[0061] 4 (treatment plan acquisition step), the treatment plan acquisition unit 64 (see FIG. 3) receives the treatment plan for the subject 12 (see FIGS. 1 and 2) transmitted from the treatment planning device 18. As described above, the treatment plan includes the CT images and isocenter coordinates of the subject 12 at a specific respiratory phase.

[0062] In step S2 (DRR image generating step), the DRR image generating unit 68 generates DRR images for each predetermined angle around the axis 38 from the CT images and isocenter coordinates included in the treatment plan. The DRR image generating unit 68 outputs the generated DRR images to the positional deviation calculation unit 70. It is desirable to execute the processes of steps S1 and S2 before irradiating the subject 12 with the radiation beam 14.

[0063] The DRR image generating unit 68 calculates a DRR image for every 1°, for example. FIG. 9 shows an example of a DRR image 79. FIG. 9 shows a DRR image 79 of the chest of the subject 12 (see FIG. 1 and FIG. 2). In FIG. 9, the up-down direction is the craniocaudal direction of the subject 12. That is, the up direction in FIG. 9 is the head direction of the subject 12. The down direction in FIG. 9 is the foot direction of the subject 12. The diaphragm 80 is also reflected in the DRR image 79 in FIG. 9. Note that FIG. 9 is a DRR image at the same rotation angle as a fluoroscopic image 81 in FIG. 10 described later.

[0064] The rotation angle sensor 40 (see FIGS. 1 to 3) can output a rotation angle including a value after the decimal point to the irradiation control device 26. Therefore, the DRR image generating unit 68 rounds off the rotation angle to one decimal place and generates a DRR image for the rotation angle converted to an integer.

[0065] To explain step S2 in FIG. 4 in more detail, the DRR image generating unit 68 (see FIG. 3) uses the machine parameters of the fluoroscopic image generating device 24 to perform simulation calculation of a DRR image from a CT image. The machine parameters include the distance from the focal point of the X-ray tube 46 to the isocenter, the distance from the focal point to the detector 48, and the size and pixel size of the detector 48. The DRR image generating unit 68 performs ray tracing for each bundle of X-rays 56 (see FIG. 2) emanating from the focal point of the X-ray tube 46, and adds up the CT values ​​on the straight lines. As a result, a DRR image equivalent to a fluoroscopic image is simulated and calculated.

[0066] Next, in order to perform radiation therapy on the tumor in the subject 12, the subject 12 is seated on the chair 28. As a result, the radiation emission port 45 (see FIG. 1) faces the subject 12. In addition, the X-ray tube 46 and the detector 48 face each other with the subject 12 and the chair 28 in between.

[0067] Next, while rotating the turntable 36 and the chair 28, X-rays 56 are irradiated from the X-ray tube 46 toward the subject 12. The detector 48 converts the irradiated X-rays 56 into an image signal. As a result, the X-rays 56 that have passed through the subject 12 are converted into an image signal according to the intensity of the X-rays. As a result, a fluoroscopic image is generated.

[0068] The computer 50 outputs a fluoroscopic image 81 of the subject 12 in a streaming manner to the irradiation controller 26. Furthermore, the rotation angle sensor 40 successively detects the rotation angles of the turntable 36 and the chair 28, and outputs the detection results to the irradiation controller 26.

[0069] Thus, in step S3 (perspective image acquiring step), the perspective image acquiring unit 66 receives the perspective images streamed out from the perspective image generating device 24. The perspective image acquiring unit 66 also receives the rotation angle of the chair 28 from the rotation angle sensor 40. The perspective image acquiring unit 66 outputs the received perspective images and the rotation angle to the positional deviation amount calculating unit 70.

[0070] Fig. 10 shows a fluoroscopic image 81 received by the fluoroscopic image acquisition unit 66 (see Fig. 3). The fluoroscopic image 81 is a fluoroscopic image of the chest of the subject 12 (see Figs. 1 and 2). In Fig. 10, the up-down direction is also the cranio-caudal direction of the subject 12. The diaphragm 82 is also captured in the fluoroscopic image 81.

[0071] In step S4 (positional deviation calculation step) of FIG. 4, the positional deviation calculation unit 70 (see FIG. 3) uses a perspective image 81 (see FIG. 10) and a DRR image 79 (see FIG. 9) with the same rotation angle to calculate the amount of respiratory deviation (positional deviation) of the diaphragm 82 of the subject 12 in the perspective image 81 when the position of the diaphragm 80 of the subject 12 in the DRR image 79 is used as a reference.

[0072] In step S5, the irradiation permission determination unit 72 determines whether the amount of positional deviation calculated by the positional deviation amount calculation unit 70 is equal to or less than a predetermined value. If the amount of positional deviation is equal to or less than the predetermined value (step S5: YES (fifth step)), the irradiation permission determination unit 72 determines that it is possible to accurately irradiate the tumor with the radiation beam 14 (see FIG. 1). Next, the irradiation permission determination unit 72 permits irradiation of the radiation beam 14, and outputs a determination result indicating permission of irradiation to the irradiation permission signal output unit 74.

[0073] In the next step S6 (irradiation permission step), the irradiation permission signal output unit 74 transmits an irradiation permission signal to the beam control device 22 based on the result of the irradiation permission determination from the irradiation permission determination unit 72. As a result, the beam control device 22 controls the radiation irradiator 20 based on the received irradiation permission signal. As a result, the radiation beam 14 can be irradiated from the radiation emission port 45 towards the subject 12.

[0074] If the amount of positional deviation exceeds a predetermined value in step S5 (step S5: NO), the irradiation permission determination unit 72 determines that the tumor cannot be accurately irradiated with the radiation beam 14. Next, the irradiation permission determination unit 72 outputs a determination result that irradiation is not permitted to the irradiation permission signal output unit 74. Based on the input determination result, the irradiation permission signal output unit 74 does not output an irradiation permission signal. Therefore, the radiation beam 14 is not irradiated to the subject 12 from the radiation emission port 45.

[0075] The outline of the operation of the first embodiment has been described above. Next, a specific example of the process of step S4 will be described with reference to the flowcharts of Figures 5 to 8. In this specific example, the positional deviation amount is calculated using the following methods (1) to (5).

[0076] (1) The positional deviation calculation unit 70 (see FIG. 3) calculates a normalized correlation coefficient between a perspective image (eg, perspective image 81 in FIG. 10) and a DRR image (eg, DRR image 79 in FIG. 9) at the same rotation angle.

[0077] (2) The positional deviation amount calculation unit 70 selects a single first partial image area (e.g., the first partial image area 84 in FIG. 11) including the diaphragm in the DRR image. The positional deviation amount calculation unit 70 selects a single second partial image area (e.g., the second partial image area 86 in FIG. 12) at the same coordinate position as the first partial image area in a perspective image having the same rotation angle as the DDR image in which the first partial image area was selected. The positional deviation amount calculation unit 70 calculates a normalized correlation coefficient between the first partial image area and the second partial image area.

[0078] (3) The positional deviation amount calculation unit 70 generates a standardized DRR image by standardizing pixel values ​​of a plurality of pixels constituting the DRR image using a first maximum pixel value, which is the maximum pixel value, and a first minimum pixel value, which is the minimum pixel value, in the first partial image region. The positional deviation amount calculation unit 70 also generates a standardized fluoroscopic image by standardizing pixel values ​​of a plurality of pixels constituting the fluoroscopic image using a second maximum pixel value, which is the maximum pixel value, and a second minimum pixel value, which is the minimum pixel value, in the second partial image region. The positional deviation amount calculation unit 70 improves the contrast of each of the DRR image and the fluoroscopic image by generating the standardized DRR image and the standardized fluoroscopic image. The positional deviation amount calculation unit 70 calculates a normalized correlation coefficient using the DRR image and the fluoroscopic image (the standardized DRR image and the standardized fluoroscopic image) with improved contrast.

[0079] (4) The positional deviation calculation unit 70 standardizes the pixel values ​​of the plurality of pixels constituting the DRR image by using the first maximum pixel value and the first minimum pixel value. The positional deviation calculation unit 70 calculates the average value of the pixel values ​​of the plurality of standardized pixels. The positional deviation calculation unit 70 generates a standardized DRR image by subtracting the average value from each of the plurality of standardized pixels. The positional deviation calculation unit 70 also standardizes the pixel values ​​of the plurality of pixels constituting the perspective image by using the second maximum pixel value and the second minimum pixel value. The positional deviation calculation unit 70 calculates the average value of the pixel values ​​of the plurality of standardized pixels. The positional deviation calculation unit 70 generates a standardized perspective image by subtracting the average value from each of the plurality of standardized pixels. The positional deviation calculation unit 70 calculates a normalized correlation coefficient by using the generated standardized DRR image and standardized perspective image.

[0080] (5) The misalignment amount calculation unit 70 generates a plurality of shifted images by shifting the fluoroscopic image, the second partial image region, or the standardized fluoroscopic image by a predetermined interval along the rostral-caudal direction within a predetermined range in the rostral-caudal direction. The misalignment amount calculation unit 70 calculates a normalized correlation coefficient between each of the generated shifted images and the DRR image, the first partial image region, or the standardized DRR image. The misalignment amount calculation unit 70 determines the shift amount corresponding to the shifted image with the maximum normalized correlation coefficient as the misalignment amount.

[0081] Fig. 5 is a flowchart showing the specific process of step S4 in Fig. 4. In the flowchart of Fig. 5, the positional deviation amount calculation unit 70 (see Fig. 3) calculates the positional deviation amount by combining the above methods (1) to (5). The specific processing operation of the positional deviation amount calculation unit 70 will be described below.

[0082] 5, the misalignment amount calculation unit 70 (see FIG. 3) calculates a normalized correlation coefficient for the perspective image and the DRR image at the same rotation angle. In step S12, the misalignment amount calculation unit 70 determines the amount of misalignment using the calculation result of the normalized correlation coefficient in step S11.

[0083] Next, steps S11 and S12 will be described in detail below.

[0084] Step S4 (see FIG. 4) is aimed at calculating the amount of misalignment of the diaphragm. It is expected that the amount of misalignment between the entire fluoroscopic image of the subject 12 (see FIG. 1 and FIG. 2) and the entire DRR image will vary spatially depending on the part in the image. Therefore, the misalignment calculation unit 70 needs to calculate the amount of misalignment by focusing on a small region including the diaphragm.

[0085] Therefore, in step S11 of FIG. 5, it is preferable that the positional deviation calculation unit 70 (see FIG. 3) calculates the positional deviation amount by using the first partial image area 84 of FIG. 11 and the second partial image area 86 of FIG. 12 instead of the DRR image 79 of FIG. 9 and the perspective image 81 of FIG. 10. FIG. 11 shows the first partial image area 84 selected from the DRR image 79 of FIG. 9. The first partial image area 84 is a single partial image area including the diaphragm 80 selected from the DRR image 79. FIG. 12 shows the second partial image area 86 selected from the perspective image 81 of FIG. 10. The second partial image area 86 is a single partial image area including the diaphragm 82 selected from the perspective image 81. The first partial image area 84 and the second partial image area 86 need to be cut out at the same coordinate position. When there is no positional deviation of the diaphragms 80, 82 between the perspective image 81 and the DRR image 79, the positional deviation amount calculation unit 70 (see FIG. 3) can calculate the positional deviation amount as 0 mm.

[0086] However, the fluoroscopic image received by the fluoroscopic image acquisition unit 66 (see FIG. 3) may not have good contrast due to the inclusion of scattered rays. For example, the image on the right side of FIG. 13 is a fluoroscopic image 92 used in radiotherapy for liver cancer. The image on the left side of FIG. 13 is a DRR image 90 corresponding to the fluoroscopic image 92. In this fluoroscopic image 92, the irradiated volume of the X-rays 56 (see FIG. 2) in the visceral region is larger than that of the fluoroscopic image 81 of lung cancer in FIG. 10. Therefore, the fluoroscopic image 92 is significantly more affected by scattered rays than the fluoroscopic image 81 (see FIG. 10). As a result, even if a normalized correlation coefficient is calculated between the DRR image 90 and the fluoroscopic image 92, the positional deviation amount may not be calculated accurately.

[0087] In this way, when the contrast is not good due to the influence of scattered radiation, in step S11 (see FIG. 5), the positional deviation calculation unit 70 (see FIG. 3) improves the contrast of at least one of the DRR image and the fluoroscopic image as follows. The DRR image is, for example, the DRR image 90 including the first partial image region 94. The fluoroscopic image is, for example, the fluoroscopic image 92 including the second partial image region 96. Specifically, the positional deviation calculation unit 70 improves the contrast of at least one of the DRR image and the fluoroscopic image by executing the following contrast improvement methods (first embodiment in FIG. 6, second embodiment in FIG. 7, and third embodiment in FIG. 8). Note that the positional deviation calculation unit 70 may use the first to third embodiments in combination. For example, the positional deviation calculation unit 70 may execute the first and second embodiments. Alternatively, the positional deviation calculation unit 70 may execute any one of the first to third embodiments.

[0088] The first embodiment will be described with reference to the flowchart of FIG. 6. The first embodiment is a method for improving the contrast of a DRR image. In step S21 of FIG. 6, the positional deviation calculation unit 70 (see FIG. 3) sets pixel values ​​of a plurality of pixels constituting the DRR image to B(i, j). i indicates a coordinate value in the horizontal direction (left-right direction) of the DRR image. j indicates a coordinate value in the vertical direction (head-to-tail direction) of the DRR image. Therefore, B(i, j) is the original pixel value of the pixel of the DRR image at the coordinate position (i, j). Moreover, the positional deviation calculation unit 70 sets the first maximum pixel value, which is the maximum pixel value, of the pixel values ​​of the plurality of pixels constituting the first partial image region of the DRR image to Bmax. Furthermore, the positional deviation calculation unit 70 sets the first minimum pixel value, which is the minimum pixel value, of the pixel values ​​of the plurality of pixels constituting the first partial image region to Bmin. Furthermore, the positional deviation calculation unit 70 sets an arbitrary constant k.

[0089] In the next step S22, the positional deviation calculation unit 70 normalizes the pixel value at the coordinate position (i, j) from B(i, j) to D(i, j) using the following formula (1). That is, the positional deviation calculation unit 70 changes the pixel value of the pixel at the coordinate position (i, j) from B(i, j) to D(i, j). D(i, j)=k{B(i, j)-Bmin} / (Bmax-Bmin) (1)

[0090] The constant k is a positive number and is preferably a positive integer within the range of 1 to 60,000.

[0091] In the next step S23, if the normalized pixel value D(i, j) is a negative number (D(i, j)<0), the positional deviation calculation unit 70 replaces the pixel value with 0 (D(i, j)→0).

[0092] A DRR image 100 (normalized DRR image) is shown on the left side of Fig. 14. The DRR image 100 is a DRR image obtained by improving the contrast of the DRR image 90 (see Fig. 13). The DRR image 100 includes a first partial image region 102. The first partial image region 102 is a partial image region obtained by improving the contrast of the first partial image region 94.

[0093] The second embodiment will be described with reference to the flow chart of FIG. 7. The second embodiment is a method for improving the contrast of a perspective image. In step S31 of FIG. 7, the positional deviation calculation unit 70 (see FIG. 3) sets pixel values ​​of a plurality of pixels constituting a perspective image to A(i, j). i indicates a coordinate value in the horizontal direction (left-right direction) of the perspective image. j indicates a coordinate value in the vertical direction (head-tail direction) of the perspective image. Therefore, A(i, j) is the original pixel value of the pixel of the perspective image at the coordinate position (i, j). Moreover, the positional deviation calculation unit 70 sets the second maximum pixel value, which is the maximum pixel value, of the pixel values ​​of the plurality of pixels constituting the second partial image region of the perspective image to Amax. Furthermore, the positional deviation calculation unit 70 sets the second minimum pixel value, which is the minimum pixel value, of the pixel values ​​of the plurality of pixels constituting the second partial image region to Amin. Furthermore, the positional deviation calculation unit 70 sets an arbitrary constant k.

[0094] In the next step S32, the positional deviation calculation unit 70 normalizes the pixel value at the coordinate position (i, j) from A(i, j) to C(i, j) using the following formula (2). That is, the positional deviation calculation unit 70 changes the pixel value of the pixel at the coordinate position (i, j) from A(i, j) to C(i, j). C(i, j)=k{A(i, j)-Amin} / (Amax-Amin) (2)

[0095] In the next step S33, if the normalized pixel value C(i, j) is a negative number (C(i, j)<0), the positional deviation calculation unit 70 replaces the pixel value with 0 (C(i, j)→0).

[0096] A perspective image 104 (normalized perspective image) is shown on the right side of Fig. 14. The perspective image 104 is a perspective image in which the contrast of the perspective image 92 (see Fig. 13) has been improved. The perspective image 104 includes a second partial image region 106. The second partial image region 106 is a partial image region in which the contrast of the second partial image region 96 has been improved.

[0097] A third embodiment will be described with reference to the flowchart of FIG. 8. The third embodiment is a method for improving the contrast of a perspective image. In step S41 of FIG. 8, the positional deviation calculation unit 70 (see FIG. 3) determines the pixel values ​​of a plurality of pixels constituting a perspective image as A(i, j), and specifies the second maximum pixel value Amax and the second minimum pixel value Amin, similarly to step S31 of FIG. 7. Furthermore, the positional deviation calculation unit 70 sets an arbitrary constant k.

[0098] In the next step S42, the positional deviation calculation unit 70 normalizes the pixel value from A(i, j) to C(i, j) using the above formula (2).

[0099] In the next step S43, similar to step S33 in FIG. 7, if the normalized pixel value C(i, j) is negative (C(i, j)<0), the misalignment calculation unit 70 replaces the pixel value with 0 (C(i, j)→0). As a result, the misalignment calculation unit 70 generates a fluoroscopic image including pixels whose pixel values ​​have been replaced with 0. In other words, the misalignment calculation unit 70 performs a correction process on the fluoroscopic image to replace negative pixel values ​​with 0, thereby generating a corrected fluoroscopic image. In the following description, the pixel value of the corrected fluoroscopic image is referred to as E(i, j).

[0100] In the next step S44, the positional deviation calculation unit 70 raises the pixel value E(i, j) of each of the multiple pixels constituting the corrected fluoroscopic image to a power of 1 to 10. For example, it is desirable for the positional deviation calculation unit 70 to raise the pixel value E(i, j) to the second to fourth power.

[0101] Fig. 15 shows a perspective image 110. The perspective image 110 is a corrected perspective image that has been subjected to a correction process in which negative pixel values ​​are replaced with 0 by the process in step S43 in Fig. 8. The perspective image 110 shows a diaphragm 112 and lung fields 114 of the subject 12 (see Fig. 1).

[0102] Fig. 16 shows a perspective image 120 in which the pixel value of each pixel in the perspective image 110 (see Fig. 15) has been raised to the fourth power by the process of step S44 in Fig. 8. It can be seen that the contrast between the diaphragm 122 and the lung field 124 is improved by raising the pixel value of each pixel to the fourth power.

[0103] The misalignment amount calculation unit 70 (see FIG. 3) calculates the misalignment amount of the diaphragm using the fluoroscopic image and the DRR image obtained as described above. Specifically, the misalignment amount calculation unit 70 extracts (selects) a single first partial image area including the diaphragm and a single second partial image area including the diaphragm for each of the fluoroscopic image and the DRR image having the same rotation angle. The misalignment amount calculation unit 70 calculates the misalignment amount of the diaphragm for the extracted first partial image area and second partial image area.

[0104] This allows the amount of positional deviation of the diaphragm to be calculated accurately. Also, the number of pixels required to calculate the normalized correlation coefficient is significantly reduced. As a result, the calculation of the normalized correlation coefficient is speeded up.

[0105] Here, the average value of multiple pixels constituting the first partial image region of the perspective image is Am. The average value of multiple pixels constituting the second partial image region of the DRR image is Bm. In this case, the normalized correlation coefficients R1 and R2 between the DRR image and the perspective image are expressed by the following formulas (3) and (4). Note that Σ is a mathematical symbol indicating the sum of pixel values, etc. for each pixel at the coordinates (i, j).

number

number

[0106] A comparison of the two normalized correlation coefficients R1 and R2 in a numerical simulation showed that the normalized correlation coefficient R1 has a larger rate of change in response to the respiratory misalignment amount than the normalized correlation coefficient R2. In other words, the normalized correlation coefficient R1 has a higher detection sensitivity for the misalignment amount than the normalized correlation coefficient R2, and is therefore more useful.

[0107] The above formulas (3) and (4) represent the normalized correlation coefficients R1 and R2 when the original DRR image (DRR image 79 in FIG. 9, DRR image 90 in FIG. 13) and the perspective image (the perspective image 81 in FIG. 10, and the perspective image 92 in FIG. 13) are used. On the other hand, the normalized correlation coefficients R3 and R4 when the contrast-improved DRR image (DRR image 100 in FIG. 14) and the perspective image (the perspective image 104 in FIG. 14, and the perspective image 120 in FIG. 16) are used are represented by the following formulas (5) and (6). Here, Cm is the average value of a plurality of pixels constituting the second partial image region (the second partial image region 106 in FIG. 14) of the perspective image with improved contrast. Dm is the average value of a plurality of pixels constituting the first partial image region (the first partial image region 102 in FIG. 14) of the DRR image with improved contrast.

number

number

[0108] As a result of comparing the two normalized correlation coefficients R3 and R4 through numerical simulation, the normalized correlation coefficient R3 has a larger rate of change in the normalized correlation coefficient with respect to the respiratory position shift amount than the normalized correlation coefficient R4. Therefore, the normalized correlation coefficient R3 has a higher detection sensitivity for the position shift amount than the normalized correlation coefficient R4, and is more useful.

[0109] Therefore, in step S11, the positional deviation amount calculation section 70 may calculate the positional deviation amount by using any one of the above-mentioned normalized correlation coefficients R1 to R4.

[0110] Next, step S12 in FIG. 5 will be described in detail.

[0111] In step S12, the positional deviation amount calculation unit 70 (see FIG. 3) determines the positional deviation amount using the calculation result of the normalized correlation coefficient in step S11. Specifically, the positional deviation amount calculation unit 70 determines the shift amount corresponding to the shift image with the maximum normalized correlation coefficient among the multiple normalized correlation coefficients as the positional deviation amount.

[0112] Fig. 13 shows the screen display of the display unit 60 (see Fig. 3) in steps S11 and S12. On the screen of the display unit 60, the image displayed on the left is a DRR image 90. The image displayed on the right is a perspective image 92 with the same rotation angle as the DRR image 90. A first partial image region 94 is displayed in the DRR image 90. A second partial image region 96 is displayed in the perspective image 92.

[0113] As described above, the normalized correlation coefficient is calculated, for example, for the first partial image region 94 and the second partial image region 96. An image 88 of a predetermined range and the calculation results of the normalized correlation coefficient is displayed in the center of the screen of the display unit 60. In this image 88, a predetermined range from -6.5 mm to +6.5 mm and the calculation results of the normalized correlation coefficient when the fluoroscopic image 92 is shifted in the cranio-caudal direction in increments of 1 mm are displayed in the vertical direction.

[0114] In the example of Fig. 13, the maximum normalized correlation coefficient is 0.951. The shift amount corresponding to the maximum normalized correlation coefficient is -0.5 mm. That is, when the perspective image 92 is shifted in the foot direction by -0.5 mm, the perspective image 92 and the DRR image 90 match best. That is, it can be concluded that the positional deviation amount is -0.5 mm.

[0115] In this case, the display unit 60 highlights the maximum normalized correlation coefficient and the shift amount corresponding to the maximum normalized correlation coefficient. For example, the maximum normalized correlation coefficient and the shift amount corresponding to the maximum normalized correlation coefficient are highlighted in red. In FIG. 13, the maximum normalized correlation coefficient and the shift amount corresponding to the maximum normalized correlation coefficient are surrounded by a thick frame. By highlighting in this manner, the user of the radiation therapy system 10 can monitor the positional deviation amount with the naked eye until the irradiation of the radiation beam 14 is completed.

[0116] Furthermore, the display unit 60 may highlight the predetermined value. In Fig. 13, the predetermined value is set to, for example, ±5 mm. In this case, for example, the position of the predetermined value is displayed with a red line. In Fig. 13, the position of the predetermined value of ±5 mm is highlighted with a dashed line. Therefore, when the amount of positional deviation is within the range of -5 mm to +5 mm, irradiation of the radiation beam 14 is permitted.

[0117] FIG. 14 is an example of a screen display of a DRR image 100 and a perspective image 104 with improved (optimized) contrast. On the screen of the display unit 60 (see FIG. 3), the image displayed on the left is the DRR image 100. The image displayed on the right is a perspective image 104 with the same rotation angle as the DRR image 100. The first partial image region 102 is displayed in the DRR image 100. The second partial image region 106 is displayed in the perspective image 104. An image 108 of a predetermined range and a calculation result of a normalized correlation coefficient is displayed in the center of the screen of the display unit 60. The display unit 60 (see FIG. 3) may highlight the image 108 in the same way as the image 88 (see FIG. 13).

[0118] For example, if the misalignment amount calculation unit 70 determines that the misalignment amount is 3 mm, the normalized correlation coefficient is the same and is maximum for a shift amount of 2.5 mm and a shift amount of 3.5 mm. Therefore, by setting the shift amount to a half integer (integer + 0.5), it becomes possible to easily perform the process of determining whether or not to permit irradiation of the radiation beam 14.

[0119] In addition, the image dimensions of both the DRR image and the fluoroscopic image are determined as images projected onto the isocenter plane, so the respiratory displacement is also discussed as the displacement on the isocenter plane.

[0120] [Effects of the first embodiment] The first embodiment has the following advantages.

[0121] 5, using fluoroscopic images 81, 92, 104 (see FIGS. 10, 13, and 14) and DRR images 79, 90, 100 (see FIGS. 9, 13, and 14) having the same rotation angle, a displacement amount (positional deviation amount) of the respiratory position of the diaphragm 82 (see FIGS. 10 and 12) in the fluoroscopic images 81, 92, 104 relative to the position of the diaphragm 80 (see FIGS. 9 and 11) of the subject 12 (see FIGS. 1 and 2) in the DRR images 79, 90, 100 is calculated. In this case, if the displacement amount is equal to or less than a predetermined value, irradiation of the radiation beam 14 from the radiation beam source 44 to the subject 12 is permitted. As a result, even if the position of the treatment target area, such as a tumor, which is the irradiated position of radiation beam 14, fluctuates periodically due to the breathing of subject 12, it is possible to accurately irradiate radiation beam 14 to the treatment target area by having subject 12 hold his / her breath so that the amount of positional deviation of diaphragm 82 is within a predetermined value.

[0122] Furthermore, the tumor (treatment target area) temporarily stops moving during quiet expiration, deep expiration, and deep inspiration. Therefore, by irradiating the treatment target area with the radiation beam 14 during quiet expiration, deep expiration, and deep inspiration, radiation therapy for the subject 12 can be performed with high accuracy.

[0123] Moreover, a plurality of shifted images are generated by shifting the second partial image regions 86, 96, 106 (see Figs. 12 to 14) in the cranio-caudal direction within a predetermined range and in increments. For each of the generated plurality of shifted images, a normalized correlation coefficient with the first partial image regions 84, 94, 102 (see Figs. 11, 13, and 14) is calculated. This makes it possible to accurately calculate the positional deviation amount of the diaphragms 80, 82. Furthermore, since the number of pixels required for calculating the normalized correlation coefficient is significantly reduced, the calculation of the normalized correlation coefficient can be speeded up.

[0124] By generating a normalized DRR image (e.g., DRR image 100) and a normalized fluoroscopic image (e.g., fluoroscopic image 104) by normalizing the DRR images 79, 90 and the fluoroscopic images 81, 92, it is possible to improve the contrast of the fluoroscopic images 81, 92 and the DRR images 79, 90. This makes it possible to more accurately calculate the positional deviation amount of the diaphragms 80, 82 using a normalized first partial image area (e.g., first partial image area 102) corresponding to the first partial image areas 84, 94 and a normalized second partial image area (e.g., second partial image area 106) corresponding to the second partial image areas 86, 96.

[0125] Moreover, by using the formulas (1) and (2), it is possible to effectively improve the contrast of each of the perspective images 81, 92 and the DRR images 79, 90. As a result, it is possible to more accurately calculate the positional deviation amounts of the diaphragms 80, 82.

[0126] For each of the pixels constituting the DRR images 79, 90, when the normalized pixel value of the pixel is a negative number, the pixel value is replaced with 0. Also, for each of the pixels constituting the perspective images 81, 92, when the normalized pixel value of the pixel is a negative number, the pixel value is replaced with 0. This makes it possible to more effectively improve the contrast of each of the perspective images 81, 92 and the DRR images 79, 90. As a result, the positional deviation amount of the diaphragms 80, 82 can be calculated more accurately.

[0127] It is possible to effectively improve the contrast of the perspective image 120 (for example, the contrast between the diaphragm 122 and the lung field 124) by generating a perspective image 120 by raising the pixel value of each of a plurality of pixels constituting the perspective image 110 to an exponent of 1 to 10. In particular, by raising the pixel value of each pixel constituting the perspective image 110 to the second to fourth power, it is possible to clearly improve the contrast between the diaphragm 122 and the lung field 124 that are captured in the perspective image 120.

[0128] Since the constant k in equations (1) and (2) is a positive number, the contrast of each of the perspective images 81, 92 and the DRR images 79, 90 can be effectively improved.

[0129] Furthermore, since the constant k is a positive integer within the range of 1 to 60,000, the contrast of each of the perspective images 81, 92 and the DRR images 79, 90 can be improved more effectively.

[0130] The predetermined range is a range of ±2 mm to ±10 mm along the cranio-caudal direction based on the anatomical shape of the subject 12 with respect to the fluoroscopic images 81, 92, and 104. The interval is within a range of 0.5 mm to 1.5 mm. This allows the amount of positional deviation to be calculated more accurately.

[0131] The predetermined range is an integer or half-integer value within ±2 mm to ±10 mm. The interval is an integer or half-integer value within a range of 0.5 mm to 1.5 mm. This makes it possible to calculate the amount of positional deviation more accurately.

[0132] The treatment plan acquisition unit 64 acquires a treatment plan including a CT image and an isocenter coordinate before the fluoroscopic image acquisition unit 66 acquires the fluoroscopic images 81, 92 and the rotation angle. This allows the DRR images 79, 90 to be calculated in advance using the CT image and the isocenter coordinate. As a result, it becomes possible to calculate the normalized correlation coefficient during radiation therapy for the subject 12.

[0133] The fluoroscopic image acquisition unit 66 acquires the fluoroscopic images 81, 92 and the rotation angle from the fluoroscopic image generation device 24 and the drive mechanism 30 via Gigabit Ethernet lines, respectively. This makes it possible to receive the fluoroscopic images 81, 92 streamed from the fluoroscopic image generation device 24 and the rotation angle output from the drive mechanism 30 in real time.

[0134] The treatment plan acquisition unit 64 acquires a treatment plan including CT images and isocenter coordinates in the DICOM-RT standard from the treatment planning device 18. This makes it possible to receive the CT images and isocenter coordinates using existing facilities.

[0135] The DRR image generating unit 68 generates DRR images 79, 90 at every predetermined angle of 0.5° to 5°. As a result, the DRR images 79, 90 are generated at intervals of, for example, 1° for all rotation angles of the chair 28, and these DRR images 79, 90 can be used as reference images for the fluoroscopic images 81, 92. As a result, when applied to rotational irradiation or intensity-modulated rotational irradiation (VMAT), radiation therapy can be performed with high accuracy even under repeated breath-holding.

[0136] The chair 28 is placed on a floor surface 32, and the subject 12 is seated on the chair 28. An axis 38 intersects with the floor surface 32, and the drive mechanism 30 can rotate the chair 28 around the axis 38. The fluoroscopic image generating device 24 is provided on the floor surface 32 so as to sandwich the chair 28. The radiation irradiation device 20 is fixed to the floor surface 32 so that the subject 12 seated on the chair 28 and the radiation beam source 44 face each other. This makes it possible to irradiate the radiation beam 14 to the subject 12 seated on the chair 28 with high accuracy. In addition, since the radiation therapy is performed with the subject 12 seated on the chair 28, the treatment floor area (floor area required to perform the radiation therapy on the subject 12) can be minimized.

[0137] [Modification of the first embodiment] Next, modified examples (first modified example and second modified example) of the first embodiment will be described. In the description of the first modified example and the second modified example, the same components as those of the radiation therapy system 10 according to the first embodiment (see Figs. 1 and 2) are designated by the same reference numerals, and detailed description thereof will be omitted.

[0138] In the above description, the chair 28 on which the subject 12 sits rotates. In a first modified example, the chair 28 may be fixed, and the radiation beam source 44 and the fluoroscopic image generating device 24 of the radiation irradiation device 20 may rotate about the axis 38. In the first modified example, for example, an annular rotating table is provided on the floor surface 32 outside the chair 28. On the rotating table, the radiation beam source 44 and the fluoroscopic image generating device 24 are arranged at predetermined angular intervals (90° intervals) around the axis of the rotating table (the vertical axis perpendicular to the floor surface 32).

[0139] In the first modified example, the perspective image acquisition section 66 acquires the rotation angle of the perspective image generating device 24 (the relative rotation angle of the chair 28 with respect to the perspective image generating device 24). By configuring the first modified example in this manner, the respective effects of the first embodiment described above can be easily obtained in the first modified example as well.

[0140] In the above description, radiation therapy is performed on a subject 12 in a sitting position. In the second modification, radiation therapy is performed on a subject 12 in a supine position. In the second modification, a gantry 150 and a bed 152 (placement unit) are placed on a floor surface 32, as shown in FIG.

[0141] An axis 154 of the gantry 150 extends horizontally along the floor surface 32. The bed 152 is movable forward and backward along the axis 154 of the gantry 150 relative to the gantry 150. The subject 12 lies on the bed 152. The subject 12 lies on the bed 152 so as to be located on the axis 154 of the gantry 150. In more detail, the subject 12 lies on the bed 152 so that a treatment target site, such as a tumor, of the subject 12 is located on the axis 154 of the gantry 150.

[0142] The radiation beam source 44 and the fluoroscopic image generating device 24 of the radiation irradiation device 20 are disposed on a gantry 150. The radiation beam source 44 and the fluoroscopic image generating device 24 are disposed on the gantry 150 at a predetermined angular interval (90° interval) around an axis 154 of the gantry 150. More specifically, the X-ray tube 46 is disposed at an angular position of 90° with respect to a radiation emission port 45 of the radiation beam source 44 around the axis 154. The detector 48 faces the X-ray tube 46 with the subject 12 sandwiched therebetween. That is, the detector 48 is disposed at an angular position of −90° with respect to the radiation emission port 45.

[0143] A driving mechanism 30 and a rotation angle sensor 40 are disposed on the gantry 150. The radiation beam source 44 and the fluoroscopic image generating device 24 are rotated around the axis 154 of the gantry 150 by the driving mechanism 30. More specifically, the radiation beam source 44 and the fluoroscopic image generating device 24 are rotated around the axis 154 of the gantry 150 by the driving mechanism 30 while facing the subject 12 in a radial direction perpendicular to the axis 154 of the gantry 150. The rotation angle sensor 40 detects the rotation angles of the radiation beam source 44 and the fluoroscopic image generating device 24 rotating around the axis 154 of the gantry 150. The gantry 150 on which the radiation beam source 44 and the fluoroscopic image generating device 24 are disposed, and the bed 152 which can advance and retreat with respect to the gantry 150 are well known (see, for example, Japanese Patent Application Laid-Open No. 2008-302129), and therefore a detailed description of their configurations will be omitted.

[0144] In the second modified example, the fluoroscopic image acquisition unit 66 acquires the rotation angle of the fluoroscopic image generating device 24 rotating around the axis 154 of the gantry 150 from the rotation angle sensor 40. By configuring in this way, the second modified example can easily obtain each of the effects of the first embodiment.

[0145] In the above description, the chair 28 (see FIGS. 1 and 2) is placed on the floor surface 32 via the drive mechanism 30. The chair 28 may be supported by a robot arm (not shown). That is, the chair 28 may be a part of a placement unit for placing the subject 12. In this case, the robot arm can position the chair 28 above the floor surface 32 with the subject 12 seated on the chair 28. In addition, the chair 28 can be positioned above the floor surface 32 at any angle with respect to the floor surface 32 by the robot arm.

[0146] In the second modified example, the bed 152 may be supported by a robot arm (not shown). That is, the bed 152 may be a part of a placement unit for placing the subject 12. In this case, the robot arm can position the bed 152 above the floor surface 32 with the subject 12 lying on the bed 152. The bed 152 can be positioned above the floor surface 32 at any angle with respect to the floor surface 32 by the robot arm.

[0147] [Configuration of the second embodiment] Fig. 18 is a configuration diagram of a radiotherapy system 200 according to the second embodiment of the present invention. The radiotherapy system 200 has a configuration obtained by partially modifying the second modification of the first embodiment (see Fig. 17). The same components as those already described are given the same reference symbols, and only the differences will be described.

[0148] Specifically, the radiation therapy system 200 includes a fluoroscopic image processing device 202 (image processing device). The fluoroscopic image processing device 202 includes an irradiation control device 26 that controls the beam control device 22. The processing unit 57 of the irradiation control device 26 includes a projection image generating unit 204, a contour line extracting unit 206, a contour line moving unit 208, and a display processing unit 210. The projection image generating unit 204, the contour line extracting unit 206, the contour line moving unit 208, and the display processing unit 210 can be realized by the processing unit 57 executing a program stored in the memory 62. The processing unit 57 may include a treatment plan acquiring unit 64, a fluoroscopic image acquiring unit 66, a DRR image generating unit 68, a positional deviation amount calculating unit 70, an irradiation permission determining unit 72, an irradiation permission signal output unit 74, and a display processing unit 76 (see FIG. 3).

[0149] The fluoroscopic image generating device 24 has an X-ray tube 46 and a detector 48. The fluoroscopic image generating device 24 does not have a computer 50 (see FIGS. 1 and 2).

[0150] In the second embodiment, the treatment plan drawn up by the treatment planning device 18 includes information on each part in the subject 12 in addition to the CT image and isocenter coordinates of the subject 12. As described above, the CT image and isocenter coordinates are three-dimensional information. Furthermore, information on each part in the subject 12 is obtained for each CT slice image. Therefore, the information on each part in the subject 12 is three-dimensional information. Examples of the three-dimensional information on each part in the subject 12 include three-dimensional information on a tumor present inside the subject 12 and three-dimensional information on organs present around the tumor. The tumor is irradiated with the radiation beam 14. It is necessary to avoid irradiating the organs present around the tumor with radiation. When the tumor moves with the breathing movement of the subject 12, the three-dimensional information on each part in the subject 12 includes diaphragm information, which is three-dimensional information on the diaphragm.

[0151] Specifically, the treatment plan includes three-dimensional information of the contours of each part inside the subject 12. Such three-dimensional information includes three-dimensional information of the contours of the tumor and three-dimensional information of the contours of the organs around the tumor. When the tumor moves in accordance with the breathing movement of the subject 12, the diaphragm information includes diaphragm contour information, which is three-dimensional information of the contour of the diaphragm.

[0152] A treatment plan including three-dimensional information of each part inside the subject 12 is transmitted from the treatment planning device 18 to the fluoroscopic image processing device 202 .

[0153] Moreover, when the perspective image generating device 24 generates a perspective image of the subject 12 , the perspective image generating device 24 transmits the perspective image of the subject 12 to the perspective image processing device 202 .

[0154] As described above, the DRR image generating unit 68 generates a DRR image, which is a virtual perspective image, from the CT image. The projection image generating unit 204 generates a projection image of the diaphragm from diaphragm information (diaphragm contour information) in the same manner as in the generation of the DRR image. Specifically, the projection image generating unit 204 generates a volumetric image (three-dimensional image) of the diaphragm by setting the pixel value inside the contour of the diaphragm to 1 and the pixel value outside the contour of the diaphragm to 0 using the diaphragm contour information. Next, the projection image generating unit 204 generates a projection image of the diaphragm by projecting the generated volumetric image onto a virtual projection surface of the perspective image.

[0155] As described above, the radiation beam source 44 and the fluoroscopic image generating device 24 rotate around the axis 154 of the gantry 150. The projection image generating unit 204 generates projection images for each arbitrary angle (projection angle) around the axis 154. The projection angles are set in increments of 1°, for example.

[0156] The contour line extraction unit 206 extracts the contour line of the diaphragm from the projection images. The contour line extraction unit 206 extracts the contour line from each projection image generated by the projection image generation unit 204 for each projection angle.

[0157] The display processing unit 210 superimposes and displays the contour lines on the perspective images. As described above, the contour line extraction unit 206 extracts (generates) the respective contour lines for each projection angle. Furthermore, the perspective image generating device 24 generates a perspective image for each projection angle. Therefore, the display processing unit 210 superimposes, on each of the multiple perspective images, a contour line having the same projection angle as the perspective image. Therefore, the display processing unit 210 can cause the display unit 60 to display the perspective images on which the contour lines are superimposed.

[0158] The contour line moving unit 208 generates a moving contour line, which is a contour line obtained by moving the contour line extracted by the contour line extraction unit 206 by a predetermined distance in the head-to-tail direction of the subject 12. In detail, the contour line moving unit 208 generates a first moving contour line, which is a contour line obtained by moving the contour line extracted by the contour line extraction unit 206 by a predetermined distance (for example, 5.0 mm) in the head direction of the subject 12. In addition, the contour line moving unit 208 generates a second moving contour line, which is a contour line obtained by moving the contour line extracted by the contour line extraction unit 206 by a predetermined distance (for example, 5.0 mm) in the foot direction of the subject 12. The display processing unit 210 may superimpose two moving contour lines on the perspective image instead of the contour line extracted by the contour line extraction unit 206. Therefore, the display processing unit 210 can display the perspective image on which the two moving contour lines are superimposed on the display unit 60. The display processing unit 210 may superimpose both the contour extracted by the contour extraction unit 206 and the moved contour (first moved contour, second moved contour) generated by the contour movement unit 208 on the perspective image.

[0159] The perspective image generating device 24, the projection image generating unit 204, the contour line extracting unit 206, the contour line moving unit 208, and the display processing unit 210 operate before or during irradiation of the subject 12 with the radiation beam 14.

[0160] The second embodiment is suitable for the case where a radiation beam 14 for rotational irradiation or VMAT is irradiated to a subject 12.

[0161] That is, in radiation therapy, it is necessary to irradiate a tumor in the subject 12 with a high dose of radiation beam 14 while minimizing the dose of radiation given to the organs surrounding the tumor. Rotational irradiation or VMAT is suitable for radiation therapy for the subject 12 because it concentrates and irradiates the radiation beam 14 on the tumor in the subject 12. For example, when performing radiation therapy on a tumor (e.g., a liver tumor) that moves with the breathing of the subject 12, the radiation beam 14 of rotational irradiation or VMAT is repeatedly irradiated to the tumor while the subject 12 is holding his / her breath, for example, by quiet exhalation. However, it is difficult to confirm the liver tumor in a fluoroscopic image. In contrast, the diaphragm is easily confirmed because it is reflected in the fluoroscopic image. In radiation therapy for such a tumor, it is desirable to sequentially check the position of the diaphragm of the subject 12 during irradiation of the radiation beam 14 of rotational irradiation or VMAT, with the position of the diaphragm in the craniocaudal direction at the time of treatment planning as a target.

[0162] Fig. 19A shows an example of a projection image 222 of the diaphragm 220 generated by the projection image generating section 204 (see Fig. 18). This projection image 222 shows a projection image of the diaphragm 220 when viewed from a direction of a specific projection angle.

[0163] Fig. 19B shows an example of a contour 224 of the diaphragm 220 extracted by the contour extraction section 206 (see Fig. 18). The contour extraction section 206 extracts the edges of the contour 224 from the projection image 222 of the diaphragm 220 (see Fig. 19A).

[0164] Fig. 20A shows an example of a perspective image 226 of the subject 12 generated by the perspective image generating device 24 (see Fig. 18). The perspective image 226 is a perspective image generated by the perspective image generating device 24 at the same gantry angle (rotation angle of the gantry 150) as the projection image 222 (see Fig. 19A). The perspective image 226 shows a diaphragm 228 of the subject 12.

[0165] 20B shows an example in which a contour line 224 is superimposed on a perspective image 226. In this example, the cranio-caudal position of the diaphragm 228 shown in the perspective image 226 and the cranio-caudal position of the contour line 224 superimposed on the perspective image 226 approximately match. That is, the user can confirm that the cranio-caudal position of the diaphragm 228 of the subject 12 while holding his / her expiratory breath matches the cranio-caudal position of the diaphragm (contour line 224) set in advance in the treatment plan.

[0166] In the rotational irradiation or VMAT, the radiation beam 14 is irradiated to the subject 12 while the gantry 150 (see FIG. 18) is continuously rotated. Therefore, it is preferable that the contour line extraction unit 206 extracts a contour line 224 (see FIG. 19B) in advance for each projection angle of 1° within the range of gantry angles of 0° to 359° before the subject 12 is irradiated with the radiation beam 14. The contour line extraction unit 206 stores information on the extracted multiple contour lines 224 in the memory 62. Furthermore, the rotation angle sensor 40 sequentially detects the gantry angle and outputs the detection result to the fluoroscopic image processing device 202. Furthermore, the fluoroscopic image generating device 24 generates a fluoroscopic image 226 (see FIG. 20A) of the subject 12 for each projection angle. Therefore, when the subject 12 is being irradiated with the radiation beam 14, the display processing unit 210 reads out, for each projection angle, the contour line 224 having the same gantry angle as the perspective image 226 from among the multiple contour lines 224 stored in the memory 62, and superimposes the read contour line 224 on the perspective image 226. In this way, when the subject 12 is being irradiated with the radiation beam 14, the display unit 60 can sequentially display the images shown in FIG.

[0167] In addition, in rotational irradiation or VMAT, it is desirable that the position of the diaphragm 228 in the cranial-caudal direction is within an allowable range of, for example, ±5 mm with respect to the position of the diaphragm set in the treatment plan. That is, in rotational irradiation or VMAT, the irradiation margin of the radiation beam 14 for the tumor in the subject 12 (see FIG. 18) is often set to 5 mm. If it is within the allowable range of ±5 mm in the cranial-caudal direction, the dose of radiation applied to the tumor is not reduced.

[0168] Therefore, the contour line moving section 208 generates a moved contour line 230 (see FIG. 21A) that is shifted ±5 mm in the cranio-caudal direction relative to the contour line 224 (see FIG. 20B). Specifically, the contour line moving section 208 generates a first moved contour line 232 by moving the contour line 224 +5 mm in the head direction of the subject 12, and a second moved contour line 234 by moving the contour line 224 −5 mm in the foot direction of the subject 12.

[0169] As shown in Fig. 21A, the display processing unit 210 (see Fig. 18) displays two moving contour lines 230 (a first moving contour line 232 and a second moving contour line 234) in a superimposed manner on a perspective image 226. In Fig. 21A, the contour line 224 is shown by a dashed line. Note that the contour line 224 is displayed in Fig. 21A for ease of understanding. When the two moving contour lines 230 are displayed in a superimposed manner in an actual perspective image 226, the contour line 224 does not need to be displayed in a superimposed manner.

[0170] 21A, the diaphragm 228 is located between the first moving contour line 232 and the second moving contour line 234 in the cranio-caudal direction. That is, the position of the diaphragm 228 in the cranio-caudal direction is within the allowable range of the diaphragm position set in the treatment plan. The user can determine that irradiation of the radiation beam 14 to the subject 12 may be continued.

[0171] In FIG. 21B, the position of the diaphragm 228 in the cranio-caudal direction deviates from the range of two moving contour lines 230 (a first moving contour line 232 and a second moving contour line 234) in the cranio-caudal direction. That is, the position of the diaphragm 228 in the cranio-caudal direction is outside the allowable range of the diaphragm position set in the treatment plan. The user can determine that it is necessary to interrupt the irradiation of the subject 12 (see FIG. 18) with the radiation beam 14. The user instructs the irradiation control device 26 to interrupt the irradiation of the radiation beam 14 by operating the operation unit 58. Note that in FIG. 21B, the interval between the first moving contour line 232 and the second moving contour line 234 in the cranio-caudal direction is set to be smaller than the interval between the first moving contour line 232 and the second moving contour line 234 in the cranio-caudal direction in FIG. 21A. This allowable range is set by the user. The allowable range is typically ±5 mm.

[0172] In rotational or VMAT, the fluoroscopic image 226 can be updated, for example, every 360 ms, allowing the user to monitor the position of the diaphragm 228 in real time as the gantry 150 (see FIG. 18) rotates.

[0173] [Operation of the second embodiment] Next, the operation (image processing method) of the radiotherapy system 200 will be described with reference to Fig. 22 and Fig. 23. In the explanation of the operation, Fig. 18 to Fig. 21B will also be referred to as necessary.

[0174] In step S51 in FIG. 22, a treatment plan including diaphragm information (diaphragm contour information) is transmitted from the treatment planning system 18 (see FIG. 18) to the fluoroscopic image processing system 202.

[0175] In step S52 (projection image generating step), the projection image generating unit 204 generates a projection image of the subject 12 (projection image 222 in FIG. 19A) using the diaphragm information.

[0176] In step S53 (contour line extraction step), the contour line extraction unit 206 extracts the contour line of the diaphragm of the subject 12 (contour line 224 in FIG. 19B) from the projection image generated by the projection image generation unit 204.

[0177] In step S54, the gantry 150 rotates and rotational irradiation of the radiation beam 14 from the radiation beam source 44 to the subject 12 begins while the subject 12 lying on the bed 152 maintains a particular respiratory phase (e.g., breath-holding state, quiet exhalation).

[0178] In step S55, the perspective image generating device 24 generates a perspective image of the subject (perspective image 226 in FIG. 20A) and transmits the generated perspective image to the perspective image processing device 202. In addition, the rotation angle sensor 40 detects the gantry angle and outputs the detection result to the perspective image processing device 202.

[0179] In step S56 (display processing step), the display processing unit 210 superimposes the contour generated by the contour extraction unit 206 on the perspective image (see FIG. 20B). The display processing unit 210 causes the display unit 60 to display the perspective image on which the contour is superimposed.

[0180] In step S57, the user checks the fluoroscopic image and contour line displayed on the display unit 60 and confirms whether the position of the diaphragm reflected in the fluoroscopic image deviates in the cranial-caudal direction from the diaphragm position preset in the treatment plan.

[0181] If the position of the diaphragm in the fluoroscopic image does not deviate in the cranio-caudal direction from the position of the diaphragm preset in the treatment plan (step S57: NO), the radiotherapy system 200 returns to step S55 and executes the processes of steps S55 to S57 again. By repeatedly executing steps S55 to S57, the fluoroscopic image and the image of the diaphragm for each projection angle are displayed on the display unit 60.

[0182] Furthermore, if the user determines that the position of the diaphragm in the fluoroscopic image deviates in the cranio-caudal direction from the position of the diaphragm set in advance in the treatment plan (step S57: YES), the radiotherapy system 200 proceeds to step S58.

[0183] In step S58, the user operates the operation unit 58 to instruct the irradiation controller 26 to interrupt the irradiation of the radiation beam 14. In response to the instruction from the user, the irradiation controller 26 interrupts the irradiation of the radiation beam 14 from the radiation beam source 44 to the subject 12. Next, the user refers to the contour line 224 appearing in the fluoroscopic image 226 to check again whether the subject 12 is maintaining a specific respiratory phase. If the subject 12 is not maintaining a specific respiratory phase, the user instructs the subject 12 to maintain a specific respiratory phase. Then, the process of step S57 is executed again.

[0184] Furthermore, when the subject 12 is irradiated with a rotational irradiation or VMAT radiation beam 14 and two moving contours (the two moving contours 230 in FIGS. 21A and 21B) are used, the radiation therapy system 200 executes the flowchart of FIG. 23.

[0185] That is, after step S51 in Fig. 22, in step S61 in Fig. 23, the projection image generating unit 204 (see Fig. 18) generates a projection image (projection image 222 in Fig. 19A) of the subject 12 for each projection angle. For example, if the projection angle is 1°, 360 projection images are generated within the gantry angle range of 0° to 359°.

[0186] In step S62, the contour extraction unit 206 extracts the contour of the diaphragm of the subject 12 (contour 224 in FIG. 19B) for each projection image for each projection angle. For example, if the projection angle is 1°, 360 contours are extracted. The extracted contours are stored in the memory 62.

[0187] In step S63, while the gantry 150 rotates and the subject 12 lying on the bed 152 maintains a particular respiratory phase (e.g., breath-holding state, quiet exhalation), irradiation of the subject 12 with a rotational irradiation or VMAT radiation beam 14 is started from the radiation beam source 44.

[0188] In step S64, the perspective image generating device 24 generates a perspective image of the subject (perspective image 226 in FIG. 20A) and transfers the generated perspective image to the perspective image processing device 202. In addition, the rotation angle sensor 40 detects the gantry angle and outputs the detection result to the perspective image processing device 202.

[0189] In step S65, the contour line moving unit 208 reads out a contour line having the same gantry angle as the fluoroscopic image from the memory 62. The contour line moving unit 208 generates two moving contour lines 230 (a first moving contour line 232 and a second moving contour line 234) by moving the read contour line in the cranio-caudal direction by a predetermined distance (e.g., ±5 mm) (see Figs. 21A and 21B). The display processing unit 210 superimposes the two moving contour lines 230 on the fluoroscopic image. The display processing unit 210 causes the display unit 60 to display the fluoroscopic image on which the two moving contour lines 230 are superimposed.

[0190] 22, the user can determine whether the position in the cranio-caudal direction of the diaphragm reflected in the perspective image is located between the first moving contour line 232 (see FIGS. 21A and 21B) and the second moving contour line 234. That is, by checking the perspective image on which the first moving contour line 232 and the second moving contour line 234 are superimposed, the user can easily determine whether the diaphragm reflected in the perspective image deviates from the gap between the first moving contour line 232 and the second moving contour line 234 (within the tolerance range of ±5 mm).

[0191] If the diaphragm is located between the first moving contour line 232 and the second moving contour line 234 (step S57: NO), the radiotherapy system 200 repeatedly executes the processes of steps S63 to S65 in FIG.

[0192] [Effects of the second embodiment] The second embodiment has the following advantages.

[0193] As shown in FIG. 22, diaphragm information of the subject 12 (see FIG. 18) included in the treatment plan is projected onto a projection surface to generate a projection image 222 (see FIG. 19A), a contour line 224 of the diaphragm (see FIG. 19B) is extracted from the projection image 222, and the contour line 224 is superimposed on a perspective image 226 (see FIGS. 20A and 20B) of the subject 12. The user checks an image in which the contour line 224 at the time of the treatment plan is superimposed on the perspective image 226. This allows the user to easily grasp, while the subject 12 is holding his / her breath, whether the position of the treatment target site such as a tumor, which is the irradiation position of the radiation beam 14, has shifted, using the diaphragm 228 that is easily visible to the user. In other words, the user can easily grasp whether the amount of positional shift of the easily visible diaphragm 228 is within an allowable range. Therefore, if the position of the diaphragm 228 deviates from the target at the time of the treatment plan, the irradiation of the radiation beam 14 to the subject 12 can be interrupted. As a result, it becomes possible to irradiate the radiation beam 14 to the treatment target area with high precision.

[0194] For example, by irradiating the radiation beam 14 to the treatment target area during quiet exhalation, it is possible to perform radiation therapy on the subject 12 with high accuracy.

[0195] As shown in FIG. 20B, it is possible to check whether the position of diaphragm 228 reflected in perspective image 226 coincides with the position of contour line 224 for each projection angle.

[0196] By setting the projection angle in increments of 1°, it is possible to accurately check whether the position of the diaphragm 228 reflected in the perspective image 226 coincides with the position of the contour line 224.

[0197] As shown in FIG. 18, the driving mechanism 30 rotates the gantry 150 about an axis 154, so that radiation therapy can be performed with high precision.

[0198] Since the subject 12 is irradiated with the radiation beam 14 for rotational irradiation or VMAT, radiation therapy can be performed with high accuracy even if the subject 12 is in a repeated breath-hold state.

[0199] The X-ray tube 46 is disposed at an angle of 90° with respect to the radiation emission port 45 around the axis 154 centered on the subject 12, and the X-ray tube 46 and the detector 48 face each other with the subject 12 in between. This makes it possible to generate a fluoroscopic image 266 of the subject 12 while the subject 12 is being irradiated with the radiation beam 14.

[0200] 21A and 21B, a contour 224 is moved in the cranio-caudal direction by an allowable range of the treatment target area preset in the treatment plan to generate a moved contour 230. This makes it easy to determine that the actual treatment target area deviates from the allowable range if the diaphragm 228 shown in the fluoroscopic image 226 deviates from the movement range of the moved contour 230. Therefore, it is possible to avoid irradiating the subject 12 with the radiation beam 14 when the actual treatment target area deviates from the allowable range.

[0201] Furthermore, if the diaphragm 228 captured in the fluoroscopic image 226 deviates from between the first moving contour line 232 and the second moving contour line 234, it can be easily determined that the actual treatment target area deviates from the allowable range.

[0202] As shown in FIG. 22, a projection image 222 (see FIG. 19A) is generated before the subject 12 (see FIG. 18) is irradiated with the radiation beam 14. A contour 224 (see FIG. 19B) is extracted before the subject 12 is irradiated with the radiation beam 14. A perspective image 226 (see FIG. 20A) is generated before or during the irradiation of the subject 12 with the radiation beam 14. As a result, the display processing unit 210 displays the moving contour 230 superimposed on the perspective image 226 before or during the irradiation of the subject 12 with the radiation beam 14 (see FIG. 20B). As a result, the perspective image 226 on which the moving contour 230 is superimposed can be displayed on the display unit 60 in real time before or during the irradiation of the subject 12 with the radiation beam 14.

[0203] [Modification of the second embodiment] Next, modified examples (third to fifth modified examples) of the second embodiment will be described.

[0204] In the third modified example shown in Fig. 24, the fluoroscopic image processing device 202 and the treatment planning device 18 are connected to an external computer 252 (image processing device) via a network 250. The external computer 252 has an operation unit 254, a display unit 256, and a memory 258 in addition to the projection image generating unit 204, the contour line extracting unit 206, the contour line moving unit 208, and the display processing unit 210. The processing unit 57 of the irradiation control device 26 does not have the projection image generating unit 204, the contour line extracting unit 206, the contour line moving unit 208, and the display processing unit 210. The operation unit 254 has the same function as the operation unit 58. The display unit 256 has the same function as the display unit 60. The memory 258 has the same function as the memory 62.

[0205] In the third modified example, the treatment planning device 18 transmits the treatment plan to the external computer 252 via the network 250. Also, the fluoroscopic image processing device 202 transmits the fluoroscopic image and the gantry angle to the external computer 252 via the network 250. The fluoroscopic image processing device 202 transfers the fluoroscopic image and the gantry angle to the external computer 252 by streaming, for example, via a gigabit Ethernet line. This allows the external computer 252 to generate the projection image 222, extract the contour 224, and generate the two moving contours 230 offline. Also, the fluoroscopic image 226 on which the contour 224 or the moving contour 230 is superimposed can be displayed in real time on the display unit 256. For example, the fluoroscopic image 226 on which the contour 224 or the moving contour 230 is superimposed can be updated and displayed on the display unit 256 every 180 ms.

[0206] The third modified example also provides the same effects as the second embodiment.

[0207] The fourth modified example shown in Fig. 25 has the same configuration as that shown in Fig. 18, except that the subject 12 is seated on a chair 28 as in the radiotherapy system 10 of the first embodiment (see Fig. 1). The fourth modified example also provides the same effects as the second embodiment.

[0208] The fifth modified example shown in Fig. 26 has the same configuration as the fourth modified example (see Fig. 25) except that an external computer 252 is provided as in the third modified example (see Fig. 24). The fifth modified example also provides the same effects as the second embodiment.

[0209] In the second embodiment and the third to fifth modifications, the treatment planning device 18 may use diaphragm information (diaphragm contour information) to move the diaphragm a predetermined distance in the cranial-caudal direction of the subject 12, thereby generating diaphragm movement information, which is information on the moved diaphragm (moving diaphragm). In this case, the projection image generating unit 204 generates a moving projection image, which is an image obtained by projecting the moving diaphragm onto a projection surface, using the diaphragm movement information. The contour line extracting unit 206 extracts a moving contour line (moving contour line 230), which is the contour line of the moving diaphragm, from the moving projection image. Even in this case, the display processing unit 210 can superimpose and display the moving contour line 230 on the perspective image 226.

[0210] Furthermore, the treatment planning device 18 may generate, as the diaphragm movement information, first diaphragm movement information which is information on a first moving diaphragm in which the diaphragm is moved 5.0 mm toward the head of the subject 12, and second diaphragm movement information which is information on a second moving diaphragm in which the diaphragm is moved 5.0 mm toward the foot of the subject 12. As a result, the projection image generating unit 204 generates a first moving projection image which is an image in which the first moving diaphragm is projected onto the projection surface using the first diaphragm movement information. Furthermore, the projection image generating unit 204 generates a second moving projection image which is an image in which the second moving diaphragm is projected onto the projection surface using the second diaphragm movement information. The contour line extracting unit 206 extracts a first moving contour line (first moving contour line 232) which is a contour line of the first moving diaphragm from the first moving projection image. Furthermore, the contour extraction unit 206 extracts a second moving contour (second moving contour 234) which is the contour of the second moving diaphragm from the second moving projection image. Even in this case, the display processing unit 210 can superimpose and display the first moving contour 232 and the second moving contour 234 on the perspective image 226.

[0211] Even in this case, the effects of the second embodiment can be obtained. Furthermore, when the first diaphragm movement information and the second diaphragm movement information are generated by the treatment planning device 18, it is necessary to generate two images (a first movement projection image and a second movement projection image) by the fluoroscopic image processing device 202 or the external computer 252. Therefore, the processing time of the fluoroscopic image processing device 202 or the external computer 252 becomes long. However, when the two images are generated by the external computer 252, the two images can be generated offline, regardless of the irradiation of the radiation beam 14 to the subject 12.

[0212] [Third embodiment] A third embodiment of the present invention will be described. In the third embodiment, in radiation therapy for a subject 12, radiation therapy according to the second embodiment (see Figs. 18 to 26) is performed, and if there is no particular problem, radiation therapy according to the first embodiment (see Figs. 1 to 17) is then performed. Specifically, when radiation therapy for a subject 12 is performed over multiple days, radiation therapy according to the second embodiment is performed on the first day (first day) of radiation therapy. In the case where the actual treatment target site does not deviate from the allowable range in radiation therapy on the first day, it can be determined that radiation therapy for the subject 12 may be continued in this state. As a result, from the second day onwards, the first embodiment is switched to the second embodiment, and radiation therapy according to the second embodiment is performed.

[0213] A fluoroscopic image (cine image) of the subject 12 is captured during irradiation with the radiation beam 14. Therefore, the image quality of the cine image varies from person to person. When the image quality of the fluoroscopic image is degraded, even if the image processing of the second embodiment can be executed, the image processing (image correlation processing) of the first embodiment may not provide a satisfactory result. In particular, when the size of the tumor is relatively large, the image quality of the cine image is likely to degrade.

[0214] Therefore, as described above, in the third embodiment, the first and second embodiments are combined to perform radiation therapy on the subject 12, so that radiation therapy can be performed on the subject 12 with high accuracy.

[0215] [Note] In addition to the above disclosure, the following notes are also disclosed.

[0216] (Appendix 1) The present invention relates to a treatment planning device (18) that creates a treatment plan for radiation therapy for a subject (12), a placement unit (28) on which the subject is placed, a fluoroscopic image generating device (24) that generates a fluoroscopic image (81, 92) of the subject when the subject is placed on the placement unit so as to be located on an axis (38) of the placement unit, a radiation irradiation device (20) having a radiation beam source (44) that irradiates a radiation beam (14) toward the subject when the subject is placed on the placement unit so as to be located on the axis, and a rotation mechanism ( and an irradiation control device (26) for controlling the radiation irradiator based on the treatment plan and the fluoroscopic image to irradiate the radiation beam towards the subject placed on the placement unit, wherein the irradiation control device includes a fluoroscopic image acquisition unit (66) for acquiring the fluoroscopic image streamed from the fluoroscopic image generation device and acquiring from the rotation mechanism a rotation angle of the placement unit when the fluoroscopic image generation device generated the fluoroscopic image, a CT image of the subject at a specific respiratory phase, and a treatment plan acquisition unit (64) that acquires from the treatment planning device the treatment plan including an isocenter coordinate for specifying an irradiation position of the radiation beam on the subject in each phase; a DRR image generation unit (68) that generates DRR images (79, 90) of the subject for each predetermined angle around the axis based on the CT images and the isocenter coordinate acquired by the treatment plan acquisition unit; and a DRR image generation unit (68) that generates DRR images (79, 90) of the subject for each predetermined angle around the axis using the fluoroscopic images and the DRR images at the same rotation angle, when the position of the diaphragm (80) of the subject in the DRR images is used as a reference. and an authorization determination unit (72) for authorizing irradiation of the radiation beam from the radiation beam source to the subject when the amount of positional deviation is equal to or less than a predetermined value, wherein the positional deviation calculation unit generates a plurality of shifted images by shifting the fluoroscopic image in a cranial-caudal direction of the subject by a predetermined interval within a predetermined range, calculates normalized correlation coefficients (R1 to R4) between the DRR image and each of the generated shifted images, and among the calculated normalized correlation coefficients,The shift amount in the cranio-caudal direction of the shifted image that maximizes the normalized correlation coefficient with respect to the perspective image is determined as the positional deviation amount.

[0217] According to the present invention, a positional deviation amount, which is a positional deviation amount of the diaphragm of the subject in the fluoroscopic image (shift image) due to respiratory movement from the position of the diaphragm in the DRR image, is calculated using a fluoroscopic image and a DRR image with the same rotation angle. If the calculated positional deviation amount is equal to or less than a predetermined value, irradiation of the radiation beam from the radiation beam source to the subject is permitted. As a result, even if the position of a treatment target site such as a tumor, which is the irradiation position of the radiation beam, periodically fluctuates due to the subject's breathing, it is possible to accurately irradiate the treatment target site with the radiation beam by having the subject hold his / her breath so that the positional deviation amount of the diaphragm is equal to or less than a predetermined value.

[0218] (Appendix 2) The present invention relates to a treatment planning apparatus for formulating a treatment plan for radiation therapy for a subject, a gantry (150), a positioning unit (152) capable of positioning the subject on an axis (154) of the gantry, a fluoroscopic image generating device disposed on the gantry and configured to generate a fluoroscopic image of the subject when the subject is positioned on the axis at the positioning unit, a radiation irradiating device having a radiation beam source disposed on the gantry and configured to irradiate a radiation beam from the radiation beam source towards the subject when the subject is positioned on the axis at the positioning unit, and a fluoroscopic image generating device configured to generate a fluoroscopic image of the subject when the subject is positioned on the axis at the positioning unit. a rotation mechanism capable of rotating a generating device and the radiation beam source around the axis, and an irradiation control device configured to control the radiation irradiator based on the treatment plan and the fluoroscopic images to irradiate the radiation beam towards the subject placed in the placement unit, wherein the irradiation control device includes a fluoroscopic image acquisition unit that acquires the fluoroscopic images streamed out from the fluoroscopic image generating device and acquires from the rotation mechanism a rotation angle of the fluoroscopic image generating device when the fluoroscopic image generating device generated the fluoroscopic image, and a treatment plan acquisition unit that acquires from the treatment planning device the treatment plan including a CT image of the body at a specific respiratory phase and an isocenter coordinate for specifying an irradiation position of the radiation beam on the subject at the specific respiratory phase; a DRR image generation unit that generates a DRR image of the subject for each predetermined angle around the axis based on the CT image and the isocenter coordinate acquired by the treatment plan acquisition unit; and a fluoroscopic image generation unit that generates a DRR image of the subject for each predetermined angle around the axis using the fluoroscopic image and the DRR image at the same rotation angle when the position of the diaphragm of the subject in the DRR image is used as a reference. a positional deviation amount calculation unit that calculates a positional deviation amount, which is a deviation amount of a respiratory position of the diaphragm of the subject in an image; and an authorization determination unit that authorizes irradiation of the radiation beam from the radiation beam source to the subject when the positional deviation amount is equal to or less than a predetermined value, wherein the positional deviation amount calculation unit generates a plurality of shifted images by shifting the fluoroscopic image in a cranial-caudal direction of the subject by a predetermined interval within a predetermined range, calculates a normalized correlation coefficient with the DRR image for each of the generated shifted images, and among the calculated normalized correlation coefficients,The shift amount in the cranio-caudal direction of the shifted image that maximizes the normalized correlation coefficient with respect to the perspective image is determined as the positional deviation amount.

[0219] According to the present invention, a positional deviation amount, which is a positional deviation amount of the diaphragm of the subject in the fluoroscopic image (shift image) due to respiratory movement from the position of the diaphragm in the DRR image, is calculated using a fluoroscopic image and a DRR image with the same rotation angle. If the calculated positional deviation amount is equal to or less than a predetermined value, irradiation of the radiation beam from the radiation beam source to the subject is permitted. As a result, even if the position of a treatment target site such as a tumor, which is the irradiation position of the radiation beam, periodically fluctuates due to the subject's breathing, it is possible to accurately irradiate the treatment target site with the radiation beam by having the subject hold his / her breath so that the positional deviation amount of the diaphragm is equal to or less than a predetermined value.

[0220] (Appendix 3) In the radiotherapy system according to Supplementary Note 1 or 2, the specific respiratory phase may be a quiet expiration, a deep expiration, or a deep inspiration of the subject.

[0221] The treatment target area is temporarily stopped during quiet expiration, deep expiration, and deep inspiration. Therefore, by irradiating the treatment target area with a radiation beam during quiet expiration, deep expiration, and deep inspiration, it is possible to perform radiation therapy on the subject with high accuracy.

[0222] (Appendix 4) In the radiation therapy system described in any one of Supplementary Notes 1 to 3, the positional deviation calculation unit may select a single first partial image area (84, 94) including the diaphragm from the DRR image, select a single second partial image area (86, 96) having the same coordinate position as that of the first partial image area from the fluoroscopic image, and shift the selected second partial image area in the cranio-caudal direction within the specified range and by the increment, thereby generating a plurality of the shifted images, and calculate the normalized correlation coefficient with the first partial image area for each of the generated shifted images.

[0223] This allows accurate calculation of the positional deviation of the diaphragm. Also, since the number of pixels required to calculate the normalized correlation coefficient is significantly reduced, the calculation of the normalized correlation coefficient can be performed at high speed.

[0224] (Appendix 5) In the radiotherapy system described in Supplementary Note 4, the positional deviation calculation unit may generate a standardized DRR image (100) by standardizing pixel values ​​of a plurality of pixels constituting the DRR image by using a first maximum pixel value that is a maximum pixel value and a first minimum pixel value that is a minimum pixel value in the first partial image region, generate a standardized fluoroscopic image (104) by standardizing pixel values ​​of a plurality of pixels constituting the fluoroscopic image by using a second maximum pixel value that is a maximum pixel value and a second minimum pixel value that is a minimum pixel value in the second partial image region, shift a standardized second partial image region (106) that is a partial image region corresponding to the second partial image region in the standardized fluoroscopic image in the cranial-caudal direction within the predetermined range and by the increment width, thereby generating a plurality of the shifted images, and calculate the normalized correlation coefficient with a standardized first partial image region (102) that is a partial image region corresponding to the first partial image region in the standardized DRR image, for each of the generated plurality of shifted images.

[0225] By generating a normalized DRR image and a normalized fluoroscopic image by normalizing the DRR image and the fluoroscopic image, the contrast of each of the fluoroscopic image and the DRR image can be improved. This makes it possible to more accurately calculate the amount of positional deviation of the diaphragm using a normalized first partial image area corresponding to the first partial image area and a normalized second partial image area (shift image) corresponding to the second partial image area.

[0226] (Appendix 6) In the radiotherapy system described in Supplementary Note 5, the positional deviation calculation unit may standardize a pixel value of each of the plurality of pixels constituting the DRR image, using the first maximum pixel value and the first minimum pixel value, calculate an average value of the pixel values ​​of the plurality of standardized pixels, and subtract the average value from each of the plurality of standardized pixels to generate the standardized DRR image, and may standardize a pixel value of each of the plurality of pixels constituting the fluoroscopic image, using the second maximum pixel value and the second minimum pixel value, calculate an average value of the pixel values ​​of the plurality of standardized pixels, and subtract the average value from each of the plurality of standardized pixels to generate the standardized fluoroscopic image.

[0227] This effectively improves the contrast of each of the fluoroscopic image and the DRR image, thereby enabling the amount of displacement of the diaphragm to be calculated more accurately.

[0228] (Appendix 7) In the radiotherapy system described in Supplementary Note 5, the positional deviation calculation unit may standardize a pixel value of each of the plurality of pixels constituting the DRR image by multiplying a difference between a pixel value of the pixel and the first minimum pixel value by an arbitrary constant (k) and dividing the obtained value by a difference between the first maximum pixel value and the first minimum pixel value, and may standardize a pixel value of each of the plurality of pixels constituting the fluoroscopic image by multiplying a difference between a pixel value of the pixel and the second minimum pixel value by the constant and dividing the obtained value by a difference between the second maximum pixel value and the second minimum pixel value.

[0229] This effectively improves the contrast of each of the fluoroscopic image and the DRR image, thereby enabling the amount of displacement of the diaphragm to be calculated more accurately.

[0230] (Appendix 8) In the radiotherapy system described in Supplementary Note 7, the positional deviation calculation unit may replace, for each of the plurality of pixels constituting the DRR image, a pixel value of the normalized pixel that is a negative number with 0, and may replace, for each of the plurality of pixels constituting the fluoroscopic image, a pixel value of the normalized pixel that is a negative number with 0.

[0231] This makes it possible to more effectively improve the contrast of each of the fluoroscopic images and the DRR images, thereby enabling the amount of displacement of the diaphragm to be calculated more accurately.

[0232] (Appendix 9) In the radiotherapy system according to Supplementary Note 8, the positional deviation calculation unit may raise a normalized pixel value of each of the plurality of pixels constituting the fluoroscopic image to a power of 1 to 10.

[0233] This makes it possible to effectively improve the contrast of a perspective image (for example, the contrast between the diaphragm and the lung field). In particular, by raising the pixel value of each pixel constituting the perspective image to the second to fourth power, the contrast between the diaphragm and the lung field captured in the perspective image can be clearly improved.

[0234] (Appendix 10) In the radiation therapy system according to Supplementary Note 7, the constant may be a positive number.

[0235] This makes it possible to effectively improve the contrast of each of the perspective image and the DRR image.

[0236] (Appendix 11) In the radiotherapy system according to Supplementary Note 10, the constant may be a positive integer in the range of 1 to 60,000.

[0237] This makes it possible to more effectively improve the contrast of each of the perspective images and the DRR images.

[0238] (Appendix 12) In the radiotherapy system described in any one of Appendices 1 to 11, the predetermined range may be within a range of ±2 mm to ±10 mm along the cranio-caudal direction based on the anatomical shape of the subject with respect to the fluoroscopic image, and the increment width may be within a range of 0.5 mm to 1.5 mm.

[0239] This allows the amount of positional deviation to be calculated more accurately.

[0240] (Appendix 13) In the radiotherapy system described in Appendix 12, the predetermined range may be an integer or half-integer value within a range of ±2 mm to ±10 mm, and the increment size may be an integer or half-integer value within a range of 0.5 mm to 1.5 mm.

[0241] This allows the amount of positional deviation to be calculated more accurately.

[0242] (Appendix 14) In the radiation therapy system described in any one of Supplementary Notes 1 to 13, the treatment plan acquisition unit may acquire the treatment plan including the CT image and the isocenter coordinate before the fluoroscopic image acquisition unit acquires the fluoroscopic image and the rotation angle.

[0243] This allows the DRR image to be calculated in advance using the CT image and the isocenter coordinates, which makes it possible to calculate the normalized correlation coefficient during radiation therapy for the subject.

[0244] (Appendix 15) In the radiation therapy system described in any one of Supplementary Notes 1 to 14, the fluoroscopic image acquisition unit may acquire the fluoroscopic image and the rotation angle from the fluoroscopic image generating device and the rotation mechanism, respectively, via a Gigabit Ethernet line.

[0245] This makes it possible to receive in real time the perspective images that are streamed out from the perspective image generating device and the rotation angles that are sequentially output from the rotation mechanism.

[0246] (Appendix 16) In the radiation therapy system according to any one of Supplementary Notes 1 to 15, the treatment plan acquisition unit may acquire the treatment plan including the CT image and the isocenter coordinates in the DICOM-RT standard from the treatment planning device.

[0247] This allows CT images and isocenter coordinates to be received using existing equipment.

[0248] (Appendix 17) In the radiotherapy system according to any one of Supplementary Notes 1 to 16, the DRR image generating unit may generate the DRR image for each of the predetermined angles of 0.5° to 5°.

[0249] This allows DRR images to be generated at intervals of, for example, 1° for all rotation angles, and these DRR images can be used as reference images for fluoroscopic images. As a result, when applied to rotational irradiation or intensity-modulated rotational irradiation (VMAT), radiation therapy can be performed with high accuracy even under repeated breath-holding.

[0250] (Appendix 18) In the radiation therapy system described in any one of Supplementary Notes 1, and 3 to 17, the positioning unit may be placed on a floor (32) or located above the floor, and may include a chair on which the subject is seated, the axis intersects the floor, the rotation mechanism is capable of rotating the chair around the axis, the fluoroscopic image generating device is provided on the floor so as to sandwich the positioning unit, and the radiation irradiation device is fixed to the floor so that the subject seated on the chair and the radiation beam source face each other and the radiation beam source is positioned at a different rotation angle from the fluoroscopic image generating device.

[0251] This allows the subject seated in a rotatable chair to be irradiated with radiation beams with high accuracy. In addition, since radiation therapy is performed on the subject seated in a chair, the treatment floor area (floor area required to perform radiation therapy on the subject) can be minimized.

[0252] (Appendix 19) a radiation therapy system (200) including: a treatment planning device that formulates a treatment plan for radiation therapy for a subject in a specific respiratory phase; a radiation irradiation device that irradiates the subject with a radiation beam based on the treatment plan; a fluoroscopic image generation device that generates a fluoroscopic image (226) of the subject; and an image processing device (202, 252) that performs predetermined image processing on the fluoroscopic image based on the treatment plan, wherein the treatment plan includes diaphragm information that is three-dimensional information of a diaphragm (220) of the subject in the specific respiratory phase, and the image processing device includes a projection image generation unit (204) that generates a projection image (222) that is an image obtained by projecting the diaphragm onto a projection surface of the fluoroscopic image using the diaphragm information; a contour extraction unit (206) that extracts a contour line (224) of the diaphragm from the projection image; and a display processing unit (210) that displays the contour line in a superimposed manner on the fluoroscopic image.

[0253] According to the present invention, the diaphragm information of the subject included in the treatment plan is projected onto a projection surface to generate a projection image, the contour of the diaphragm is extracted from the projection image, and the contour is superimposed on the fluoroscopic image of the subject. The user checks the image in which the contour at the time of the treatment plan is superimposed on the fluoroscopic image. This allows the user to easily grasp whether the position of the treatment target site, such as a tumor, which is the irradiation position of the radiation beam, has shifted while the subject is holding his / her breath, by using the diaphragm which is easily visible. In other words, the user can easily grasp whether the amount of positional shift of the diaphragm which is easily visible is within an allowable range. Therefore, if the position of the diaphragm deviates from the target at the time of the treatment plan, the irradiation of the radiation beam to the subject can be interrupted. As a result, the radiation beam can be accurately irradiated to the treatment target site.

[0254] (Appendix 20) In the radiation therapy system according to Supplementary Note 19, the specific respiratory phase may be quiet exhalation.

[0255] By irradiating a radiation beam to a treatment target area while the subject is breathing quietly, it is possible to perform radiation therapy on the subject with high accuracy.

[0256] (Appendix 21) In the radiotherapy system described in Supplementary Note 19 or 20, the radiotherapy system may further include a positioning unit which positions the subject on a predetermined axis, the projection image generating unit generates the projection images for each arbitrary projection angle around the axis, the contour line extracting unit extracts the contour line from each of the projection images generated for each projection angle, the perspective image generating device generates the perspective images for each projection angle, and the display processing unit may superimpose and display the contour line at the same angle as the perspective images around the axis on each of the perspective images generated for each projection angle.

[0257] This makes it possible to check whether the position of the diaphragm reflected in the perspective image coincides with the position of the contour line for each projection angle.

[0258] (Appendix 22) In the radiotherapy system according to Supplementary Note 21, the setting interval of the projection angle may be 1°.

[0259] By setting the projection angle in 1° increments, it is possible to accurately check whether the position of the diaphragm reflected in the fluoroscopic image matches the position of the contour line.

[0260] (Appendix 23) In the radiation therapy system described in Appendix 21 or 22, the radiation therapy system may further include a gantry and a first rotation mechanism (30), the axis being an axis of the gantry, the radiation irradiation device and the fluoroscopic image generating device being disposed in the gantry, and the first rotation mechanism may rotate the radiation irradiation device and the fluoroscopic image generating device around the axis.

[0261] This allows radiation therapy to be performed with high precision.

[0262] (Appendix 24) In the radiotherapy system according to Supplementary Note 21 or 22, the radiotherapy system may further include a second rotation mechanism (30) that rotates the placement unit about the axis.

[0263] This allows radiation therapy to be performed with high precision.

[0264] (Appendix 25) In the radiotherapy system according to any one of Supplementary Notes 19 to 24, the radiation irradiator may irradiate the subject with the radiation beam for intensity modulated rotary irradiation.

[0265] This allows radiation therapy to be performed with high accuracy even when the subject is undergoing repeated breath-holding.

[0266] (Appendix 26) In the radiation therapy system described in any of Appendices 19 to 25, the radiation irradiation device may have an irradiation port (45) that irradiates the radiation beam toward the subject, and the fluoroscopic image generating device may have an X-ray tube (46) that is arranged at an angular position of 90° with respect to the irradiation port around an axis centered on the subject and irradiates X-rays (56) toward the subject, and an X-ray detector (48) that faces the X-ray tube across the subject and generates the fluoroscopic image based on the X-rays that have passed through the subject.

[0267] This makes it possible to generate a fluoroscopic image of the subject while the subject is being irradiated with the radiation beam.

[0268] (Appendix 27) In the radiation therapy system described in any one of Appendices 19 to 26, the image processing device may further include a contour line moving unit (208) that generates a moved contour line (230) by moving the contour line a predetermined distance in the cranial-caudal direction of the subject, and the display processing unit may superimpose and display the moved contour line on the fluoroscopic image.

[0269] The contour line is moved in the cranio-caudal direction by the allowable range of the treatment target area set in advance in the treatment plan, to generate the moved contour line. In this way, if the diaphragm shown in the fluoroscopic image is outside the moving range of the moved contour line, it can be easily determined that the actual treatment target area is outside the allowable range. As a result, it is possible to avoid irradiating the subject with the radiation beam when the actual treatment target area is outside the allowable range.

[0270] (Appendix 28) In the radiation therapy system described in Appendix 27, the moving contour line may include a first moving contour line (232) that is moved 5.0 mm toward the subject's head, and a second moving contour line (234) that is moved 5.0 mm toward the subject's foot.

[0271] As a result, if the diaphragm captured in the fluoroscopic image deviates from between the first moving contour line and the second moving contour line, it can be easily determined that the actual treatment target area deviates from the allowable range.

[0272] (Appendix 29) In the radiation therapy system described in any one of Appendices 19 to 26, the diaphragm information includes diaphragm movement information, which is information about a moving diaphragm in which the diaphragm is moved a predetermined distance in the cranial-caudal direction of the subject, the projection image generation unit uses the diaphragm movement information to generate a moving projection image, which is an image of the moving diaphragm projected onto the projection surface, the contour extraction unit extracts a moving contour, which is the contour of the moving diaphragm, from the moving projection image, and the display processing unit may superimpose and display the moving contour on the perspective image.

[0273] Diaphragm movement information in which the diaphragm is moved in the cranio-caudal direction by the tolerance of the treatment target area is included in the treatment plan. This allows a movement projection image to be generated from the diaphragm movement information, and a movement contour line to be generated from the generated movement projection image. Even in this case, if the diaphragm reflected in the fluoroscopic image deviates from the movement range of the movement contour line, it can be easily determined that the actual treatment target area deviates from the tolerance range. As a result, it is possible to avoid irradiating the subject with a radiation beam when the actual treatment target area deviates from the tolerance range.

[0274] (Appendix 30) In the radiation therapy system described in Appendix 29, the diaphragm movement information may include first diaphragm movement information which is information on a first moving diaphragm in which the diaphragm is moved 5.0 mm toward the subject's head, and second diaphragm movement information which is information on a second moving diaphragm in which the diaphragm is moved 5.0 mm toward the subject's feet.

[0275] Even in this case, if the diaphragm shown in the fluoroscopic image deviates from between the first moving contour line based on the first diaphragm movement information and the second moving contour line based on the second diaphragm movement information, it can be easily determined that the actual treatment target area deviates from the acceptable range.

[0276] (Appendix 31) In the radiation therapy system described in any one of Supplementary Notes 19 to 30, the projection image generating unit may generate the projection image before the radiation beam is irradiated to the subject, the contour extraction unit may extract the contour before the radiation beam is irradiated to the subject, the perspective image generating device may generate the perspective image before the radiation beam is irradiated to the subject or during the irradiation of the radiation beam to the subject, and the display processing unit may superimpose and display the contour on the perspective image before the radiation beam is irradiated to the subject or during the irradiation of the radiation beam to the subject.

[0277] This makes it possible to display a fluoroscopic image with a contour line superimposed thereon in real time before or during irradiation of the subject with radiation.

[0278] (Appendix 32) a radiation irradiation device having a radiation beam source that irradiates a radiation beam toward the subject based on the treatment plan when the subject is arranged on the arrangement unit so as to be located on the axis line of the arrangement unit; an image processing device that performs predetermined image processing on the fluoroscopic image based on the treatment plan; a rotation mechanism that can rotate the arrangement unit about the axis line; and an irradiation control device that controls the radiation irradiation device based on the treatment plan and the fluoroscopic image to irradiate the radiation beam toward the subject arranged on the arrangement unit, wherein the treatment plan includes diaphragm information that is three-dimensional information of the diaphragm of the subject in the specific respiratory phase, and the image processing device includes a projection image generation unit that generates a projection image that is an image obtained by projecting the diaphragm onto a projection surface of the fluoroscopic image using the diaphragm information, and a projection image generation unit that generates a projection image that is an image obtained by projecting the diaphragm onto a projection surface of the fluoroscopic image using the projection image. the irradiation control device includes a contour extraction unit which extracts a contour of a membrane, and a display processing unit which displays the contour in a superimposed manner on the perspective image, and the irradiation control device executes a predetermined control process after processing by the image processing device, acquires the perspective image streamed out from the perspective image generating device, and acquires from the rotation mechanism a rotation angle of the placement unit when the perspective image generating device generated the perspective image, and a treatment plan acquisition unit that acquires the treatment plan including the isocenter coordinates from the treatment planning device; a DRR image generation unit that generates a DRR image of the subject for each predetermined angle around the axis based on the CT images and the isocenter coordinates acquired by the treatment plan acquisition unit; a positional deviation calculation unit that calculates a positional deviation amount, which is a positional deviation amount of the respiratory position of the subject's diaphragm in the fluoroscopic image when the position of the subject's diaphragm in the DRR image is used as a reference, using the fluoroscopic image and the DRR image at the same rotation angle; andand a permission determination unit that permits irradiation of the radiation beam from the radiation beam source to the subject, wherein the positional deviation calculation unit generates a plurality of shifted images by shifting the fluoroscopic image in a cranial-caudal direction of the subject at a predetermined interval within a predetermined range, calculates a normalized correlation coefficient with the DRR image for each of the generated shifted images, and determines, as the positional deviation amount, a shift amount in the cranial-caudal direction with respect to the fluoroscopic image of a shifted image having a maximum normalized correlation coefficient among the calculated normalized correlation coefficients.

[0279] According to the present invention, first, radiation therapy is performed on the subject based on the above image processing, and if there are no particular problems, radiation therapy is then performed on the subject based on the above irradiation control processing, which makes it possible to perform radiation therapy on the subject with high accuracy.

[0280] (Appendix 33) a radiation irradiation device having a radiation beam source disposed on the gantry and causing a radiation beam to be irradiated from the radiation beam source to the subject based on the treatment plan when the subject is disposed on the axis at the positioning unit; an image processing device which performs predetermined image processing on the fluoroscopic image based on the treatment plan; a rotation mechanism which is capable of rotating the fluoroscopic image generating device and the radiation beam source around the axis; and an irradiation control device which controls the radiation irradiation device based on the treatment plan and the fluoroscopic image to irradiate the radiation beam to the subject disposed on the positioning unit, wherein the treatment plan includes diaphragm information which is three-dimensional information of the diaphragm of the subject in the specific respiratory phase, and the image processing device controls the radiation irradiation device based on the treatment plan and the fluoroscopic image to irradiate the radiation beam to the subject disposed on the positioning unit, The processing device has a projection image generating unit that generates a projection image, which is an image obtained by projecting the diaphragm onto a projection surface of the perspective image, using the diaphragm information, a contour line extracting unit that extracts a contour line of the diaphragm from the projection image, and a display processing unit that displays the contour line superimposed on the perspective image. The irradiation control device executes a predetermined control process after processing by the image processing device, acquires the perspective image streamed from the perspective image generating device, and pre-registers a rotation angle of the perspective image generating device when the perspective image generating device generated the perspective image. a fluoroscopic image acquisition unit that acquires images from the rotation mechanism; a treatment plan acquisition unit that acquires the treatment plan from the treatment planning device, the treatment plan including a CT image of the subject in a specific respiratory phase and an isocenter coordinate for specifying an irradiation position of the radiation beam on the subject in the specific respiratory phase; a DRR image generation unit that generates a DRR image of the subject for each predetermined angle around the axis based on the CT image and the isocenter coordinate acquired by the treatment plan acquisition unit;and a permission determination unit that permits irradiation of the radiation beam from the radiation beam source to the subject when the amount of positional displacement is equal to or less than a predetermined value, wherein the positional displacement calculation unit generates a plurality of shifted images by shifting the fluoroscopic image in a cranial-caudal direction of the subject by a predetermined interval within a predetermined range, calculates a normalized correlation coefficient with the DRR image for each of the generated shifted images, and determines, as the amount of positional displacement, a shift amount in the cranial-caudal direction relative to the fluoroscopic image of a shifted image having a maximum normalized correlation coefficient among the calculated normalized correlation coefficients.

[0281] According to the present invention, first, radiation therapy is performed on the subject based on the above image processing, and if there are no particular problems, radiation therapy is then performed on the subject based on the above irradiation control processing, which makes it possible to perform radiation therapy on the subject with high accuracy.

[0282] (Appendix 34) an irradiation control device that controls irradiation of a radiation beam from a radiation beam source of a radiation irradiating device to a subject based on a treatment plan for radiation therapy for the subject and a fluoroscopic image of the subject, the subject is placed on a positioning unit, the fluoroscopic image is generated by a fluoroscopic image generating device when the subject is placed on the positioning unit so as to be located on an axis line of the positioning unit, the positioning unit is rotatable about the axis line by a rotation mechanism, the irradiation control device includes a fluoroscopic image acquiring unit that acquires the fluoroscopic image streamed out from the fluoroscopic image generating device and acquires from the rotation mechanism a rotation angle of the positioning unit when the fluoroscopic image generating device generated the fluoroscopic image, a treatment plan acquiring unit that acquires from a treatment planning device the treatment plan including a CT image of the subject in a specific respiratory phase and an isocenter coordinate for specifying an irradiation position of the radiation beam of the subject in the specific respiratory phase, and a CT image acquired by the treatment plan acquiring unit. a misalignment amount calculation unit that calculates a misalignment amount, which is a misalignment amount of a respiratory position of the subject's diaphragm in the fluoroscopic image when the position of the subject's diaphragm in the DRR image is used as a reference, using the fluoroscopic image and the DRR image at the same rotation angle; and a permission determination unit that permits irradiation of the radiation beam from the radiation beam source to the subject when the misalignment amount is equal to or less than a predetermined value. The misalignment amount calculation unit generates a plurality of shifted images by shifting the fluoroscopic image in a cranio-caudal direction of the subject by a predetermined increment within a predetermined range, calculates a normalized correlation coefficient with the DRR image for each of the generated shifted images, and determines a shift amount in the cranio-caudal direction of the shifted image with a maximum normalized correlation coefficient among the calculated normalized correlation coefficients, relative to the fluoroscopic image, as the misalignment amount.

[0283] (Appendix 35) an irradiation control device that controls irradiation of a radiation beam from a radiation beam source of a radiation irradiating device to a subject based on a treatment plan for radiation therapy for the subject and a fluoroscopic image of the subject, the subject is disposed on an axis of a gantry by a positioning unit, the fluoroscopic image is generated by a fluoroscopic image generating device disposed on the gantry when the subject is disposed on the axis by the positioning unit, the radiation beam source is disposed on the gantry and irradiates the radiation beam toward the subject when the subject is disposed on the axis by the positioning unit, the fluoroscopic image generating device and the radiation beam source are rotatable around the axis by a rotation mechanism, the irradiation control device further comprises a fluoroscopic image acquiring unit that acquires the fluoroscopic image streamed out from the fluoroscopic image generating device and acquires from the rotation mechanism a rotation angle of the fluoroscopic image generating device when the fluoroscopic image was generated by the fluoroscopic image, and a treatment plan acquisition unit that acquires the treatment plan including the target from a treatment planning device; a DRR image generation unit that generates a DRR image of the subject for each predetermined angle around the axis based on the CT image and the isocenter coordinate acquired by the treatment plan acquisition unit; a positional deviation amount calculation unit that calculates a positional deviation amount, which is a positional deviation amount of the respiratory position of the subject's diaphragm in the fluoroscopic image when the position of the subject's diaphragm in the DRR image is used as a reference, using the fluoroscopic image and the DRR image at the same rotation angle; and and a permission determination unit that, at a certain time, permits irradiation of the radiation beam from the radiation beam source to the subject, wherein the positional deviation calculation unit generates a plurality of shifted images by shifting the fluoroscopic image in a cranial-caudal direction of the subject at a predetermined increment within a predetermined range, calculates a normalized correlation coefficient with the DRR image for each of the generated shifted images, and determines, as the positional deviation amount, a shift amount in the cranial-caudal direction with respect to the fluoroscopic image of the shifted image having a maximum normalized correlation coefficient among the calculated normalized correlation coefficients.

[0284] (Appendix 36) An image processing device that performs predetermined image processing on a fluoroscopic image of a subject generated by a fluoroscopic image generating device based on a treatment plan for radiation therapy for the subject in a specific respiratory phase, the treatment plan including diaphragm information that is three-dimensional information of the diaphragm of the subject in the specific respiratory phase, the image processing device having a projection image generating unit that uses the diaphragm information to generate a projection image that is an image of the diaphragm projected onto a projection surface of the fluoroscopic image, a contour line extraction unit that extracts a contour line of the diaphragm from the projection image, and a display processing unit that superimposes and displays the contour line on the fluoroscopic image.

[0285] (Appendix 37) A processing device that performs predetermined image processing on a fluoroscopic image of a subject generated by a fluoroscopic image generating device based on a treatment plan for radiation therapy for a subject in a specific respiratory phase, and then controls irradiation of a radiation beam from a radiation beam source of a radiation irradiation device to the subject based on the treatment plan and the fluoroscopic image, wherein the treatment plan includes diaphragm information that is three-dimensional information of the diaphragm of the subject in the specific respiratory phase, and the processing device has an image processing device and an irradiation control device, and the image processing device converts the diaphragm into the fluoroscopic image using the diaphragm information. a projection image generating unit that generates a projection image that is an image projected onto a projection surface of the diaphragm, a contour line extracting unit that extracts a contour line of the diaphragm from the projection image, and a display processing unit that displays the contour line superimposed on the perspective image, wherein the subject is placed on a placement unit, and the perspective image is generated by a perspective image generating device when the subject is placed on the placement unit so as to be located on an axis line of the placement unit, and the placement unit is rotatable around the axis line by a rotation mechanism, and the irradiation control device executes a predetermined control process after processing by the image processing device, and outputs a control signal from the perspective image generating device to the projection image generating unit. a fluoroscopic image acquisition unit that acquires the fluoroscopic images streamed from the patient's body and acquires from the rotation mechanism a rotation angle of the placement unit when the fluoroscopic image generation device generated the fluoroscopic images; a treatment plan acquisition unit that acquires from a treatment planning device the treatment plan including a CT image of the patient in a specific respiratory phase and an isocenter coordinate for specifying an irradiation position of the patient with the radiation beam in the specific respiratory phase; and a DRR image of the patient for each predetermined angle around the axis based on the CT image and the isocenter coordinate acquired by the treatment plan acquisition unit. a misalignment amount calculation unit that calculates a misalignment amount, which is an amount of misalignment of a respiratory position of the subject's diaphragm in the fluoroscopic image when the position of the subject's diaphragm in the DRR image is used as a reference, using the fluoroscopic image and the DRR image at the same rotation angle; and a permission determination unit that permits irradiation of the radiation beam from the radiation beam source to the subject when the misalignment amount is equal to or less than a predetermined value, wherein the misalignment amount calculation unit shifts the fluoroscopic image in a cranial-caudal direction of the subject by a predetermined interval within a predetermined range, therebya processing device that generates a plurality of shifted images, calculates a normalized correlation coefficient between each of the generated shifted images and the DRR image, and determines, as the positional deviation amount, a shift amount in the cranio-caudal direction with respect to the perspective image of a shifted image having a maximum normalized correlation coefficient among the calculated normalized correlation coefficients.

[0286] (Appendix 38) A processing device that performs predetermined image processing on a fluoroscopic image of a subject generated by a fluoroscopic image generating device based on a treatment plan for radiation therapy for a subject in a specific respiratory phase, and then controls irradiation of a radiation beam from a radiation beam source of a radiation irradiation device to the subject based on the treatment plan and the fluoroscopic image, wherein the treatment plan includes diaphragm information that is three-dimensional information of the diaphragm of the subject in the specific respiratory phase, the processing device has an image processing device and an irradiation control device, and the image processing device uses the diaphragm information to image the diaphragm from the fluoroscopic image. a projection image generating unit that generates a projection image that is an image projected onto a projection surface, a contour line extracting unit that extracts a contour line of the diaphragm from the projection image, and a display processing unit that displays the contour line superimposed on the perspective image, wherein the subject is placed on an axis of a gantry by a positioning unit, and the perspective image is generated by a perspective image generating device that is placed on the gantry when the subject is placed on the axis by the positioning unit, and the radiation beam source is placed on the gantry, and the radiation beam is directed to the subject when the subject is placed on the axis by the positioning unit. the irradiation control device executes a predetermined control process after processing by the image processing device, acquires the fluoroscopic image streamed out from the fluoroscopic image generating device, and acquires from the rotation mechanism a rotation angle of the fluoroscopic image generating device when the fluoroscopic image is generated by the fluoroscopic image generating device; a treatment plan acquisition unit that acquires the treatment plan including the isocenter coordinate from a treatment planning device; a DRR image generation unit that generates a DRR image of the subject for each predetermined angle around the axis based on the CT images and the isocenter coordinate acquired by the treatment plan acquisition unit; a positional deviation calculation unit that calculates a positional deviation amount, which is a positional deviation amount of the respiratory position of the subject's diaphragm in the fluoroscopic image when the position of the subject's diaphragm in the DRR image is used as a reference, using the fluoroscopic image and the DRR image at the same rotation angle; andand a permission determination unit that permits irradiation of the radiation beam from the radiation beam source to the subject, wherein the positional deviation calculation unit generates a plurality of shifted images by shifting the fluoroscopic image in a cranial-caudal direction of the subject at a predetermined interval within a predetermined range, calculates a normalized correlation coefficient with the DRR image for each of the generated shifted images, and determines, as the positional deviation amount, a shift amount in the cranial-caudal direction with respect to the fluoroscopic image of a shifted image having a maximum normalized correlation coefficient among the calculated normalized correlation coefficients.

[0287] (Appendix 39) 1. An irradiation control method for controlling irradiation of a radiation beam from a radiation beam source of a radiation irradiation device to a subject, based on a treatment plan for radiation therapy for the subject and a fluoroscopic image of the subject, the subject is placed on a positioning unit, the fluoroscopic image is generated by a fluoroscopic image generating device when the subject is placed on the positioning unit so as to be located on an axis line of the positioning unit, and the positioning unit is rotatable about the axis line by a rotation mechanism, the irradiation control method includes a treatment plan acquisition step (S1) of acquiring the treatment plan including a CT image of the subject in a specific respiratory phase and an isocenter coordinate for specifying an irradiation position of the subject of the radiation beam in the specific respiratory phase, a DRR image generation step (S2) of generating DRR images of the subject for each predetermined angle about the axis line based on the acquired CT image and the isocenter coordinate, and a fluoroscopic image generation step (S3) of acquiring the fluoroscopic image streamed out from the fluoroscopic image generation device, the fluoroscopic image generation device generating the fluoroscopic image. the positional deviation amount calculating step (S4) of calculating, using the fluoroscopic image and the DRR image at the same rotation angle, a positional deviation amount which is a deviation amount of a respiratory position of the diaphragm of the subject in the fluoroscopic image when the position of the diaphragm of the subject in the DRR image is used as a reference; and an irradiation permission step (S5) of permitting irradiation of the radiation beam from the radiation beam source to the subject when the positional deviation amount is equal to or less than a predetermined value, wherein in the positional deviation amount calculating step, a plurality of shifted images are generated by shifting the fluoroscopic image in a cranio-caudal direction of the subject by a predetermined increment within a predetermined range, a normalized correlation coefficient with the DRR image is calculated for each of the generated shifted images, and a shift amount in the cranio-caudal direction of the shifted image with a maximum normalized correlation coefficient among the calculated normalized correlation coefficients is determined as the positional deviation amount.

[0288] (Appendix 40) An irradiation control method for controlling irradiation of a radiation beam from a radiation beam source of a radiation irradiation device to a subject based on a treatment plan for radiation therapy for the subject and a fluoroscopic image of the subject, the subject is placed on an axis of a gantry by a positioning unit, the fluoroscopic image is generated by a fluoroscopic image generating device placed on the gantry when the subject is placed on the axis by the positioning unit, the radiation beam source is placed on the gantry and irradiates the radiation beam toward the subject when the subject is placed on the axis by the positioning unit, and the fluoroscopic image generating device and the radiation beam source are rotatable around the axis by a rotation mechanism, the irradiation control method comprising: a treatment plan acquisition step of acquiring the treatment plan including a CT image of the subject in a specific respiratory phase and an isocenter coordinate for specifying an irradiation position of the radiation beam of the subject in the specific respiratory phase; a DRR image generation step of generating a DRR image of the subject for each predetermined angle around the axis based on the acquired CT image and the isocenter coordinate; a fluoroscopic image acquiring step of acquiring the fluoroscopic image streamed out from the fluoroscopic image generating device and acquiring from the rotation mechanism a rotation angle of the fluoroscopic image generating device when the fluoroscopic image generating device generated the fluoroscopic image; a positional deviation amount calculating step of calculating a positional deviation amount, which is a positional deviation amount of the respiratory position of the diaphragm of the subject in the fluoroscopic image when the position of the diaphragm of the subject in the DRR image is used as a reference, using the fluoroscopic image and the DRR image at the same rotation angle; and an irradiation permission step of permitting irradiation of the radiation beam from the radiation beam source to the subject, wherein the positional deviation calculation step generates a plurality of shifted images by shifting the fluoroscopic image in a cranial-caudal direction of the subject within a predetermined range at predetermined intervals, calculates a normalized correlation coefficient with the DRR image for each of the generated shifted images, and determines, as the positional deviation amount, a shift amount in the cranial-caudal direction with respect to the fluoroscopic image of the shifted image having a maximum normalized correlation coefficient among the calculated normalized correlation coefficients.

[0289] (Appendix 41) An image processing method for performing predetermined image processing on a fluoroscopic image of a subject generated by a fluoroscopic image generating device based on a treatment plan for radiation therapy for the subject in a specific respiratory phase, the treatment plan including diaphragm information that is three-dimensional information of the diaphragm of the subject in the specific respiratory phase, the image processing method including a projection image generating step (S52) for generating a projection image that is an image of the diaphragm projected onto a projection surface of the fluoroscopic image using the diaphragm information, a contour line extraction step (S53) for extracting a contour line of the diaphragm from the projection image, and a display processing step (S56) for superimposing and displaying the contour line on the fluoroscopic image.

[0290] (Appendix 42) A processing method for performing a predetermined image processing on a fluoroscopic image of a subject generated by a fluoroscopic image generating device based on a treatment plan for radiation therapy for the subject in a specific respiratory phase, and then controlling irradiation of a radiation beam from a radiation beam source of a radiation irradiation device to the subject based on the treatment plan and the fluoroscopic image, wherein the treatment plan includes diaphragm information that is three-dimensional information of the diaphragm of the subject in the specific respiratory phase, the subject is placed on a placement unit, and the fluoroscopic image is placed on the placement unit so that the subject is located on an axis line of the placement unit. a fluoroscopic image generating device that generates a fluoroscopic image when the diaphragm is projected onto a projection surface of the fluoroscopic image, the placement unit being rotatable around the axis by a rotation mechanism, and the processing method includes a projection image generating step of generating a projection image, which is an image obtained by projecting the diaphragm onto a projection surface of the fluoroscopic image, using the diaphragm information; a contour line extracting step of extracting a contour line of the diaphragm from the projection image; a display processing step of superimposing and displaying the contour line on the fluoroscopic image; and, after the display processing step, displaying a CT image of the subject in the specific respiratory phase and a radiation beam image of the subject in the specific respiratory phase. a treatment plan acquisition step of acquiring the treatment plan including an isocenter coordinate for specifying an irradiation position of the target object; a DRR image generation step of generating a DRR image of the target object for each predetermined angle around the axis based on the acquired CT images and the isocenter coordinate; a fluoroscopic image acquisition step of acquiring the fluoroscopic images streamed out from the fluoroscopic image generation device and acquiring from the rotation mechanism a rotation angle of the placement unit when the fluoroscopic image generation device generated the fluoroscopic images; and an irradiation permission step of permitting irradiation of the radiation beam from the radiation beam source to the subject when the positional deviation amount is equal to or less than a predetermined value. In the positional deviation calculation step, a plurality of shifted images are generated by shifting the fluoroscopic image in a cranial-caudal direction of the subject by a predetermined interval within a predetermined range, and for each of the generated shifted images,A normalized correlation coefficient with the DRR image is calculated, and the shift amount in the cranio-caudal direction of the shift image with the maximum normalized correlation coefficient among the calculated normalized correlation coefficients is determined as the positional deviation amount.

[0291] (Appendix 43) A processing method for performing predetermined image processing on a fluoroscopic image of a subject generated by a fluoroscopic image generating device based on a treatment plan for radiation therapy for the subject in a specific respiratory phase, and then controlling irradiation of a radiation beam from a radiation beam source of a radiation irradiation device to the subject based on the treatment plan and the fluoroscopic image, wherein the treatment plan includes diaphragm information that is three-dimensional information of the diaphragm of the subject in the specific respiratory phase, the subject is placed on an axis of a gantry by a positioning unit, and the fluoroscopic image is generated when the subject is placed on the axis by the positioning unit. a fluoroscopic image generating device disposed on the gantry, the radiation beam source is disposed on the gantry, and irradiates the radiation beam toward the subject when the subject is disposed on the axis by the positioning unit, the fluoroscopic image generating device and the radiation beam source are rotatable about the axis by a rotation mechanism, and the processing method includes a projection image generating step of generating a projection image, which is an image obtained by projecting the diaphragm onto a projection surface of the fluoroscopic image, using the diaphragm information, and a contour line extracting step of extracting a contour line of the diaphragm from the projection image. a display processing step of superimposing and displaying the contour line on the fluoroscopic image; a treatment plan acquisition step of acquiring, after execution of the display processing step, the treatment plan including a CT image in the specific respiratory phase and an isocenter coordinate for specifying an irradiation position of the radiation beam on the subject in the specific respiratory phase; a DRR image generation step of generating a DRR image of the subject for each predetermined angle around the axis based on the acquired CT image and the isocenter coordinate; acquiring the fluoroscopic images streamed out from the fluoroscopic image generation device; the method includes a fluoroscopic image acquiring step of acquiring, from the rotation mechanism, a rotation angle of the fluoroscopic image generating device when the fluoroscopic image generating device generated the fluoroscopic image; a positional deviation calculating step of calculating, using the fluoroscopic image and the DRR image at the same rotation angle, a positional deviation amount which is a positional deviation amount of a respiratory position of the diaphragm of the subject in the fluoroscopic image when the position of the diaphragm of the subject in the DRR image is used as a reference; and an irradiation permitting step of permitting irradiation of the radiation beam from the radiation beam source to the subject when the positional deviation amount is equal to or less than a predetermined value,In the positional deviation calculation step, a plurality of shifted images are generated by shifting the fluoroscopic image in a cranio-caudal direction of the subject within a predetermined range at a predetermined interval, a normalized correlation coefficient between each of the generated shifted images and the DRR image is calculated, and a shift amount in the cranio-caudal direction with respect to the fluoroscopic image of the shifted image having the maximum normalized correlation coefficient among the calculated normalized correlation coefficients is determined as the positional deviation amount.

[0292] (Appendix 44) A program for causing a computer (26) to execute at least one of the irradiation control method described in Appendix 39 or 40, the image processing method described in Appendix 41, and the processing method described in Appendix 42 or 43.

[0293] (Appendix 45) A storage medium (62, 258) that stores the program described in Appendix 44.

[0294] The present invention is not limited to the above disclosure, and various configurations can be adopted without departing from the gist of the present invention. [Explanation of symbols]

[0295] 10, 200...Radiation therapy system 12...Subject 14. Radiation beam 18...Treatment planning device 20…Radiation irradiation device 24...Fluoroscopic image generating device 26... Irradiation control device (computer) 28...Chair (arrangement part) 30...Drive mechanism (rotation mechanism) 38, 154...axis line 44...Radiation beam source 62, 258...Memory (storage medium) 64…Treatment Plan Acquisition Department 66…Fluoroscopic image acquisition unit 68…DRR image generation section 70... Position deviation calculation unit 72…Irradiation permission determination unit (permission determination unit) 79, 90, 100…DRR images 80, 82, 112, 122, 220, 228…Diaphragm 81, 92, 104, 110, 120, 226…X-ray images 150…gantry 152…Bed (placement area) 202... Fluoroscopy image processing device (image processing device) 204...projection image generating unit 206...Contour line extraction unit 210...Display processing unit 222…Projected image 224…Contour line 252...External computer (image processing device)

Claims

1. a treatment planning device that creates a treatment plan for radiation therapy for a subject; a placement unit on which the subject is placed; and a fluoroscopic image generating device that generates a fluoroscopic image of the subject when the subject is placed on the placement unit so as to be located on an axis of the placement unit; a radiation irradiation device having a radiation beam source that irradiates a radiation beam toward the subject when the subject is placed on the placement unit so as to be located on the axis; a rotation mechanism capable of rotating the arrangement portion around the axis; an irradiation control device that controls the radiation irradiator based on the treatment plan and the fluoroscopic image to irradiate the radiation beam toward the subject placed in the placement unit; A radiation therapy system comprising: The irradiation control device includes: a perspective image acquisition unit that acquires the perspective images streamed from the perspective image generation device and acquires from the rotation mechanism a rotation angle of the arrangement unit when the perspective image generation device generates the perspective image; a treatment plan acquisition unit that acquires, from the treatment planning device, the treatment plan including a CT image of the subject in a specific respiratory phase and an isocenter coordinate for specifying an irradiation position of the radiation beam on the subject in the specific respiratory phase; a DRR image generating unit that generates DRR images of the subject for each predetermined angle around the axis based on the CT images and the isocenter coordinates acquired by the treatment plan acquisition unit; a positional deviation amount calculation unit that calculates a positional deviation amount, which is a deviation amount of a respiratory position of the diaphragm of the subject in the fluoroscopic image when a position of the diaphragm of the subject in the DRR image is used as a reference, by using the fluoroscopic image and the DRR image at the same rotation angle; a permission determination unit that permits irradiation of the radiation beam from the radiation beam source to the subject when the amount of positional deviation is equal to or less than a predetermined value; having The positional deviation amount calculation unit generating a plurality of shifted images by shifting the fluoroscopic image in a cranial-caudal direction of the subject within a predetermined range at a predetermined interval; Calculating a normalized correlation coefficient between each of the generated shift images and the DRR image; a shift amount in the cranio-caudal direction relative to the fluoroscopic image of a shift image that has a maximum normalized correlation coefficient among the calculated normalized correlation coefficients, is determined as the positional deviation amount.

2. a treatment planning device that creates a treatment plan for radiation therapy for a subject; The gantry, a positioning unit capable of positioning the subject on an axis of the gantry; a fluoroscopic image generating device that is disposed on the gantry and generates a fluoroscopic image of the subject when the subject is disposed on the axis by the positioning unit; a radiation irradiation device having a radiation beam source disposed on the gantry, and irradiating a radiation beam from the radiation beam source towards the subject when the subject is disposed on the axis at the positioning unit; a rotation mechanism capable of rotating the fluoroscopic image generating device and the radiation beam source about the axis; an irradiation control device that controls the radiation irradiator based on the treatment plan and the fluoroscopic image to irradiate the radiation beam toward the subject placed in the placement unit; A radiation therapy system comprising: The irradiation control device includes: a perspective image acquiring unit that acquires the perspective images streamed out from the perspective image generating device and acquires from the rotation mechanism a rotation angle of the perspective image generating device at the time when the perspective image generating device generated the perspective image; a treatment plan acquisition unit that acquires, from the treatment planning device, the treatment plan including a CT image of the subject in a specific respiratory phase and an isocenter coordinate for specifying an irradiation position of the radiation beam on the subject in the specific respiratory phase; a DRR image generating unit that generates DRR images of the subject for each predetermined angle around the axis based on the CT images and the isocenter coordinates acquired by the treatment plan acquisition unit; a positional deviation amount calculation unit that calculates a positional deviation amount, which is a deviation amount of a respiratory position of the diaphragm of the subject in the fluoroscopic image when a position of the diaphragm of the subject in the DRR image is used as a reference, by using the fluoroscopic image and the DRR image at the same rotation angle; a permission determination unit that permits irradiation of the radiation beam from the radiation beam source to the subject when the amount of positional deviation is equal to or less than a predetermined value; having The positional deviation amount calculation unit generating a plurality of shifted images by shifting the fluoroscopic image in a cranial-caudal direction of the subject within a predetermined range at a predetermined interval; Calculating a normalized correlation coefficient between each of the generated shift images and the DRR image; a shift amount in the cranio-caudal direction relative to the fluoroscopic image of a shift image that has a maximum normalized correlation coefficient among the calculated normalized correlation coefficients, is determined as the positional deviation amount.

3. 3. The radiation therapy system according to claim 1, A radiation therapy system, wherein the particular respiratory phase is a quiet exhalation, a deep exhalation, or a deep inhalation of the subject.

4. 3. The radiation therapy system according to claim 1, The positional deviation amount calculation unit selecting a single first partial image region including the diaphragm from the DRR image; selecting a single second partial image area having the same coordinate position as the first partial image area from the perspective image; Shifting the selected second partial image area in the head-to-tail direction within the predetermined range by the increment width to generate a plurality of shifted images; A radiation therapy system that calculates the normalized correlation coefficient with the first partial image region for each of the generated multiple shift images.

5. 5. The radiation therapy system according to claim 4, The positional deviation amount calculation unit generating a standardized DRR image by standardizing pixel values ​​of a plurality of pixels constituting the DRR image using a first maximum pixel value that is a maximum pixel value and a first minimum pixel value that is a minimum pixel value in the first partial image region; generating a standardized perspective image by standardizing pixel values ​​of a plurality of pixels constituting the perspective image using a second maximum pixel value that is a maximum pixel value and a second minimum pixel value that is a minimum pixel value in the second partial image region; a standardized second partial image region, which is a partial image region corresponding to the second partial image region, of the standardized perspective image is shifted in the cranio-caudal direction within the predetermined range by the increment width to generate a plurality of the shifted images; A radiation therapy system that calculates, for each of the generated multiple shift images, the normalized correlation coefficient with a normalized first partial image region, which is a partial image region of the normalized DRR image corresponding to the first partial image region.

6. 6. The radiation therapy system according to claim 5, The positional deviation amount calculation unit using the first maximum pixel value and the first minimum pixel value, standardizing a pixel value of each of the plurality of pixels constituting the DRR image, calculating an average value of the pixel values ​​of the standardized plurality of pixels, and subtracting the average value from the pixel values ​​of each of the plurality of standardized pixels to generate the standardized DRR image; a radiotherapy system which uses the second maximum pixel value and the second minimum pixel value to standardize a pixel value of each of the plurality of pixels constituting the fluoroscopic image, calculates an average value of the pixel values ​​of the standardized plurality of pixels, and subtracts the average value from the pixel values ​​of each of the plurality of standardized pixels to generate the standardized fluoroscopic image.

7. 6. The radiation therapy system according to claim 5, The positional deviation amount calculation unit standardizing a pixel value of each of the plurality of pixels constituting the DRR image by multiplying a difference between the pixel value of the pixel and the first minimum pixel value by an arbitrary constant and dividing the resultant value by a difference between the first maximum pixel value and the first minimum pixel value; and normalizing a pixel value of each of the plurality of pixels constituting the fluoroscopic image by multiplying a difference between the pixel value of the pixel and the second minimum pixel value by the constant and dividing the resultant value by a difference between the second maximum pixel value and the second minimum pixel value.

8. 8. The radiation therapy system according to claim 7, The positional deviation amount calculation unit For each of the plurality of pixels constituting the DRR image, when the normalized pixel value of the pixel is a negative number, the pixel value is replaced with 0; and a radiotherapy system for replacing each of the plurality of pixels constituting the fluoroscopic image with a pixel value of 0 when the normalized pixel value of the pixel is a negative number.

9. 9. The radiation therapy system according to claim 8, The positional deviation calculation unit raises a normalized pixel value of each of the plurality of pixels constituting the fluoroscopic image to a power of 1 to 10.

10. 8. The radiation therapy system according to claim 7, A radiation therapy system, wherein the constant is a positive number.

11. 11. The radiation therapy system of claim 10, A radiation therapy system, wherein the constant is a positive integer in the range of 1 to 60,000.

12. 3. The radiation therapy system according to claim 1, the predetermined range is within a range of ±2 mm to ±10 mm along the cranio-caudal direction in accordance with the anatomical shape of the subject with respect to the fluoroscopic image; A radiation therapy system, wherein the step size is within a range of 0.5 mm to 1.5 mm.

13. 13. The radiation therapy system of claim 12, The predetermined range is an integer or half integer value between ±2 mm and ±10 mm, A radiation therapy system, wherein the step size is an integer or half integer value within a range of 0.5 mm to 1.5 mm.

14. 3. The radiation therapy system according to claim 1, A radiation therapy system, wherein the treatment plan acquisition unit acquires the treatment plan including the CT image and the isocenter coordinate before the fluoroscopic image acquisition unit acquires the fluoroscopic image and the rotation angle.

15. 3. The radiation therapy system according to claim 1, a fluoroscopic image acquisition unit that acquires the fluoroscopic image and the rotation angle from the fluoroscopic image generating device and the rotation mechanism, respectively, via a Gigabit Ethernet line.

16. 3. The radiation therapy system according to claim 1, The treatment plan acquisition unit acquires the treatment plan including the CT images and the isocenter coordinates in the DICOM-RT standard from the treatment planning device.

17. 3. The radiation therapy system according to claim 1, A radiation therapy system, wherein the DRR image generating unit generates the DRR image for each of the predetermined angles of 0.5° to 5°.

18. 2. The radiation therapy system according to claim 1, the placement unit is placed on a floor surface or is located above the floor surface and includes a chair on which the subject sits; The axis intersects with the floor surface, The rotation mechanism is capable of rotating the chair around the axis, the perspective image generating devices are provided on the floor surface so as to sandwich the placement unit, a radiation irradiation device fixed to the floor surface such that the subject seated in the chair faces the radiation beam source and the radiation beam source is positioned at a different rotation angle from the fluoroscopic image generating device.

19. A treatment planning device that creates a treatment plan for radiation therapy for a subject in a specific respiratory phase; a radiation irradiation device that irradiates the subject with a radiation beam based on the treatment plan; a perspective image generating device for generating a perspective image of the subject; an image processing device that performs predetermined image processing on the fluoroscopic images based on the treatment plan; A radiation therapy system comprising: the treatment plan includes diaphragm information, which is three-dimensional information of the diaphragm of the subject in the specific respiratory phase; The image processing device includes: a projection image generating unit that generates a projection image by projecting the diaphragm onto a projection surface of the perspective image using the diaphragm information; a contour line extraction unit that extracts a contour line of the diaphragm from the projection image; a display processing unit that displays the contour line superimposed on the perspective image; A radiation therapy system comprising:

20. 20. The radiation therapy system of claim 19, A radiation therapy system, wherein the particular breathing phase is quiet exhalation.

21. 21. The radiation therapy system according to claim 19, A positioning unit that positions the subject on a predetermined axis, the projection image generating unit generates the projection image for each arbitrary projection angle around the axis; the contour extraction unit extracts the contour from each of the projection images generated for each of the projection angles; the perspective image generating device generates the perspective image for each of the projection angles; The display processing unit superimposes the contour line at the same angle around the axis as the fluoroscopic image on each of the fluoroscopic images generated for each projection angle.

22. 22. The radiation therapy system of claim 21, A radiation therapy system, wherein the setting interval of the projection angles is 1°.

23. 22. The radiation therapy system of claim 21, Further comprising a gantry and a first rotation mechanism; the axis is the axis of the gantry, the radiation irradiation device and the fluoroscopic image generating device are disposed on the gantry, A radiation therapy system, wherein the first rotation mechanism rotates the radiation irradiating device and the fluoroscopic image generating device around the axis.

24. 22. The radiation therapy system of claim 21, The radiation therapy system further includes a second rotation mechanism that rotates the placement unit about the axis.

25. 21. The radiation therapy system according to claim 19, The radiation irradiation device is a radiation therapy system that irradiates the subject with the radiation beam for intensity modulated rotary irradiation.

26. 21. The radiation therapy system according to claim 19, the radiation irradiation device has an irradiation port that irradiates the radiation beam toward the subject, The fluoroscopic image generating device comprises: an X-ray tube that is disposed at an angle of 90° with respect to the irradiation port around an axis centered on the subject and irradiates X-rays toward the subject; an X-ray detector that faces the X-ray tube across the subject and generates the fluoroscopic image based on the X-rays that have passed through the subject; A radiation therapy system comprising:

27. 21. The radiation therapy system according to claim 19, The image processing device further includes a contour line moving unit that generates a moved contour line by moving the contour line by a predetermined distance in a cranial-caudal direction of the subject, The display processing unit displays the moving contour line superimposed on the fluoroscopic image.

28. 28. The radiation therapy system of claim 27, A radiation therapy system, wherein the moving contour line includes a first moving contour line obtained by moving the contour line 5.0 mm toward the subject's head, and a second moving contour line obtained by moving the contour line 5.0 mm toward the subject's feet.

29. 21. The radiation therapy system according to claim 19, The diaphragm information includes diaphragm movement information, which is information on a moved diaphragm in which the diaphragm is moved a predetermined distance in a cranial-caudal direction of the subject, the projection image generation unit generates a moving projection image, which is an image obtained by projecting the moving diaphragm onto the projection surface, using the diaphragm movement information; The contour line extraction unit extracts a moving contour line, which is a contour line of the moving diaphragm, from the moving projection image, The display processing unit displays the moving contour line superimposed on the fluoroscopic image.

30. 30. The radiation therapy system of claim 29, A radiation therapy system, wherein the diaphragm movement information includes first diaphragm movement information, which is information on a first moving diaphragm that moves the diaphragm 5.0 mm toward the subject's head, and second diaphragm movement information, which is information on a second moving diaphragm that moves the diaphragm 5.0 mm toward the subject's feet.

31. 21. The radiation therapy system according to claim 19, the projection image generating unit generates the projection image before the radiation beam is irradiated onto the subject; the contour extraction unit extracts the contour before irradiating the object with the radiation beam; the fluoroscopic image generating device generates the fluoroscopic image before or during irradiation of the subject with the radiation beam, The display processing unit displays the contour line superimposed on the fluoroscopic image before or during irradiation of the subject with the radiation beam.

32. A treatment planning device that creates a treatment plan for radiation therapy for a subject in a specific respiratory phase; a placement unit on which the subject is placed; and a fluoroscopic image generating device that generates a fluoroscopic image of the subject when the subject is placed on the placement unit so as to be located on an axis of the placement unit; a radiation irradiation device having a radiation beam source that irradiates a radiation beam toward the subject based on the treatment plan when the subject is placed on the placement unit so as to be located on the axis; an image processing device that performs predetermined image processing on the fluoroscopic images based on the treatment plan; a rotation mechanism capable of rotating the arrangement portion around the axis; an irradiation control device that controls the radiation irradiator based on the treatment plan and the fluoroscopic image to irradiate the radiation beam toward the subject placed in the placement unit; A radiation therapy system comprising: the treatment plan includes diaphragm information, which is three-dimensional information of the diaphragm of the subject in the specific respiratory phase; The image processing device includes: a projection image generating unit that generates a projection image by projecting the diaphragm onto a projection surface of the perspective image using the diaphragm information; a contour line extraction unit that extracts a contour line of the diaphragm from the projection image; a display processing unit that displays the contour line superimposed on the perspective image; having the irradiation control device executes a predetermined control process after the process of the image processing device; a perspective image acquisition unit that acquires the perspective images streamed from the perspective image generation device and acquires from the rotation mechanism a rotation angle of the arrangement unit when the perspective image generation device generates the perspective image; a treatment plan acquisition unit that acquires, from the treatment planning device, the treatment plan including a CT image of the subject in a specific respiratory phase and an isocenter coordinate for specifying an irradiation position of the radiation beam on the subject in the specific respiratory phase; a DRR image generating unit that generates DRR images of the subject for each predetermined angle around the axis based on the CT images and the isocenter coordinates acquired by the treatment plan acquisition unit; a positional deviation amount calculation unit that calculates a positional deviation amount, which is a deviation amount of a respiratory position of the diaphragm of the subject in the fluoroscopic image when a position of the diaphragm of the subject in the DRR image is used as a reference, by using the fluoroscopic image and the DRR image at the same rotation angle; a permission determination unit that permits irradiation of the radiation beam from the radiation beam source to the subject when the amount of positional deviation is equal to or less than a predetermined value; having The positional deviation amount calculation unit generating a plurality of shifted images by shifting the fluoroscopic image in a cranial-caudal direction of the subject within a predetermined range at a predetermined interval; Calculating a normalized correlation coefficient between each of the generated shift images and the DRR image; a shift amount in the cranio-caudal direction relative to the fluoroscopic image of a shift image that has a maximum normalized correlation coefficient among the calculated normalized correlation coefficients, is determined as the positional deviation amount.

33. A treatment planning device that creates a treatment plan for radiation therapy for a subject in a specific respiratory phase; The gantry, a positioning unit capable of positioning the subject on an axis of the gantry; a fluoroscopic image generating device that is disposed on the gantry and generates a fluoroscopic image of the subject when the subject is disposed on the axis by the positioning unit; a radiation irradiation device having a radiation beam source disposed on the gantry, and irradiating a radiation beam from the radiation beam source to the subject based on the treatment plan when the subject is disposed on the axis by the positioning unit; an image processing device that performs predetermined image processing on the fluoroscopic images based on the treatment plan; a rotation mechanism capable of rotating the fluoroscopic image generating device and the radiation beam source about the axis; an irradiation control device that controls the radiation irradiator based on the treatment plan and the fluoroscopic image to irradiate the radiation beam toward the subject placed in the placement unit; A radiation therapy system comprising: the treatment plan includes diaphragm information, which is three-dimensional information of the diaphragm of the subject in the specific respiratory phase; The image processing device includes: a projection image generating unit that generates a projection image by projecting the diaphragm onto a projection surface of the perspective image using the diaphragm information; a contour line extraction unit that extracts a contour line of the diaphragm from the projection image; a display processing unit that displays the contour line superimposed on the perspective image; having the irradiation control device executes a predetermined control process after the process of the image processing device; a perspective image acquiring unit that acquires the perspective images streamed out from the perspective image generating device and acquires from the rotation mechanism a rotation angle of the perspective image generating device at the time when the perspective image generating device generated the perspective image; a treatment plan acquisition unit that acquires, from the treatment planning device, the treatment plan including a CT image of the subject in a specific respiratory phase and an isocenter coordinate for specifying an irradiation position of the radiation beam on the subject in the specific respiratory phase; a DRR image generating unit that generates DRR images of the subject for each predetermined angle around the axis based on the CT images and the isocenter coordinates acquired by the treatment plan acquisition unit; a positional deviation amount calculation unit that calculates a positional deviation amount, which is a deviation amount of a respiratory position of the diaphragm of the subject in the fluoroscopic image when a position of the diaphragm of the subject in the DRR image is used as a reference, by using the fluoroscopic image and the DRR image at the same rotation angle; a permission determination unit that permits irradiation of the radiation beam from the radiation beam source to the subject when the amount of positional deviation is equal to or less than a predetermined value; having The positional deviation amount calculation unit generating a plurality of shifted images by shifting the fluoroscopic image in a cranial-caudal direction of the subject within a predetermined range at a predetermined interval; Calculating a normalized correlation coefficient between each of the generated shift images and the DRR image; a shift amount in the cranio-caudal direction relative to the fluoroscopic image of a shift image that has a maximum normalized correlation coefficient among the calculated normalized correlation coefficients, is determined as the positional deviation amount.

34. An irradiation control device that controls irradiation of a radiation beam from a radiation beam source of a radiation irradiation device to a subject based on a treatment plan for radiation therapy for the subject and a fluoroscopic image of the subject, The subject is placed on a placement section, the fluoroscopic image is generated by a fluoroscopic image generating device when the subject is placed on the placement unit so as to be located on an axis of the placement unit; The arrangement portion is rotatable about the axis by a rotation mechanism, The irradiation control device includes: a perspective image acquisition unit that acquires the perspective images streamed from the perspective image generation device and acquires from the rotation mechanism a rotation angle of the arrangement unit when the perspective image generation device generates the perspective image; a treatment plan acquisition unit that acquires, from a treatment planning device, the treatment plan including a CT image of the subject in a specific respiratory phase and an isocenter coordinate for specifying an irradiation position of the radiation beam on the subject in the specific respiratory phase; a DRR image generating unit that generates DRR images of the subject for each predetermined angle around the axis based on the CT images and the isocenter coordinates acquired by the treatment plan acquisition unit; a positional deviation amount calculation unit that calculates a positional deviation amount, which is a deviation amount of a respiratory position of the diaphragm of the subject in the fluoroscopic image when a position of the diaphragm of the subject in the DRR image is used as a reference, by using the fluoroscopic image and the DRR image at the same rotation angle; a permission determination unit that permits irradiation of the radiation beam from the radiation beam source to the subject when the amount of positional deviation is equal to or less than a predetermined value; having The positional deviation amount calculation unit generating a plurality of shifted images by shifting the fluoroscopic image in a cranial-caudal direction of the subject within a predetermined range at a predetermined interval; Calculating a normalized correlation coefficient between each of the generated shift images and the DRR image; an irradiation control device that determines, as the amount of positional deviation, an amount of shift in the cranio-caudal direction with respect to the fluoroscopic image of a shifted image that has a maximum normalized correlation coefficient among the calculated normalized correlation coefficients.

35. An irradiation control device that controls irradiation of a radiation beam from a radiation beam source of a radiation irradiation device to a subject based on a treatment plan for radiation therapy for the subject and a fluoroscopic image of the subject, The subject is placed on the axis of a gantry in a placement section, the fluoroscopic image is generated by a fluoroscopic image generating device disposed on the gantry when the subject is disposed on the axis in the placement unit; the radiation beam source is disposed in the gantry, and irradiates the radiation beam toward the subject when the subject is disposed on the axis line at the positioning unit; the fluoroscopic image generating device and the radiation beam source are rotatable about the axis by a rotation mechanism; The irradiation control device includes: a perspective image acquiring unit that acquires the perspective images streamed out from the perspective image generating device and acquires from the rotation mechanism a rotation angle of the perspective image generating device at the time when the perspective image generating device generated the perspective image; a treatment plan acquisition unit that acquires, from a treatment planning device, the treatment plan including a CT image of the subject in a specific respiratory phase and an isocenter coordinate for specifying an irradiation position of the radiation beam on the subject in the specific respiratory phase; a DRR image generating unit that generates DRR images of the subject for each predetermined angle around the axis based on the CT images and the isocenter coordinates acquired by the treatment plan acquisition unit; a positional deviation amount calculation unit that calculates a positional deviation amount, which is a deviation amount of a respiratory position of the diaphragm of the subject in the fluoroscopic image when a position of the diaphragm of the subject in the DRR image is used as a reference, by using the fluoroscopic image and the DRR image at the same rotation angle; a permission determination unit that permits irradiation of the radiation beam from the radiation beam source to the subject when the amount of positional deviation is equal to or less than a predetermined value; having The positional deviation amount calculation unit generating a plurality of shifted images by shifting the fluoroscopic image in a cranial-caudal direction of the subject within a predetermined range at a predetermined interval; Calculating a normalized correlation coefficient between each of the generated shift images and the DRR image; an irradiation control device that determines, as the amount of positional deviation, an amount of shift in the cranio-caudal direction with respect to the fluoroscopic image of a shifted image that has a maximum normalized correlation coefficient among the calculated normalized correlation coefficients.

36. 1. An image processing device that performs a predetermined image processing on a fluoroscopic image of a subject generated by a fluoroscopic image generating device based on a treatment plan for radiation therapy for the subject in a specific respiratory phase, the treatment plan includes diaphragm information, which is three-dimensional information of the diaphragm of the subject in the specific respiratory phase; The image processing device includes: a projection image generating unit that generates a projection image by projecting the diaphragm onto a projection surface of the perspective image using the diaphragm information; a contour line extraction unit that extracts a contour line of the diaphragm from the projection image; a display processing unit that displays the contour line superimposed on the perspective image; The image processing device includes:

37. a processing device that performs a predetermined image processing on a fluoroscopic image of a subject generated by a fluoroscopic image generating device based on a treatment plan of radiation therapy for the subject in a specific respiratory phase, and then controls irradiation of a radiation beam from a radiation beam source of a radiation irradiation device to the subject based on the treatment plan and the fluoroscopic image, the treatment plan includes diaphragm information, which is three-dimensional information of the diaphragm of the subject in the specific respiratory phase; The processing device includes an image processing device and an irradiation control device, The image processing device includes: a projection image generating unit that generates a projection image by projecting the diaphragm onto a projection surface of the perspective image using the diaphragm information; a contour line extraction unit that extracts a contour line of the diaphragm from the projection image; a display processing unit that displays the contour line superimposed on the perspective image; having The subject is placed on a placement section, the fluoroscopic image is generated by a fluoroscopic image generating device when the subject is placed on the placement unit so as to be located on an axis of the placement unit; The arrangement portion is rotatable about the axis by a rotation mechanism, the irradiation control device executes a predetermined control process after the process of the image processing device; a perspective image acquisition unit that acquires the perspective images streamed from the perspective image generation device and acquires from the rotation mechanism a rotation angle of the arrangement unit when the perspective image generation device generates the perspective image; a treatment plan acquisition unit that acquires, from a treatment planning device, the treatment plan including a CT image of the subject in a specific respiratory phase and an isocenter coordinate for specifying an irradiation position of the radiation beam on the subject in the specific respiratory phase; a DRR image generating unit that generates DRR images of the subject for each predetermined angle around the axis based on the CT images and the isocenter coordinates acquired by the treatment plan acquisition unit; a positional deviation amount calculation unit that calculates a positional deviation amount, which is a deviation amount of a respiratory position of the diaphragm of the subject in the fluoroscopic image when a position of the diaphragm of the subject in the DRR image is used as a reference, by using the fluoroscopic image and the DRR image at the same rotation angle; a permission determination unit that permits irradiation of the radiation beam from the radiation beam source to the subject when the amount of positional deviation is equal to or less than a predetermined value; having The positional deviation amount calculation unit generating a plurality of shifted images by shifting the fluoroscopic image in a cranial-caudal direction of the subject within a predetermined range at a predetermined interval; Calculating a normalized correlation coefficient between each of the generated shift images and the DRR image; a processing device that determines, as the positional deviation amount, a shift amount in the cranio-caudal direction with respect to the perspective image of a shift image that has a maximum normalized correlation coefficient among the calculated normalized correlation coefficients.

38. a processing device that performs a predetermined image processing on a fluoroscopic image of a subject generated by a fluoroscopic image generating device based on a treatment plan of radiation therapy for the subject in a specific respiratory phase, and then controls irradiation of a radiation beam from a radiation beam source of a radiation irradiation device to the subject based on the treatment plan and the fluoroscopic image, the treatment plan includes diaphragm information, which is three-dimensional information of the diaphragm of the subject in the specific respiratory phase; The processing device includes an image processing device and an irradiation control device, The image processing device includes: a projection image generating unit that generates a projection image by projecting the diaphragm onto a projection surface of the perspective image using the diaphragm information; a contour line extraction unit that extracts a contour line of the diaphragm from the projection image; a display processing unit that displays the contour line superimposed on the perspective image; having The subject is placed on the axis of a gantry in a placement section, the fluoroscopic image is generated by a fluoroscopic image generating device disposed on the gantry when the subject is disposed on the axis in the placement unit; the radiation beam source is disposed in the gantry, and irradiates the radiation beam toward the subject when the subject is disposed on the axis line at the positioning unit; the fluoroscopic image generating device and the radiation beam source are rotatable about the axis by a rotation mechanism; the irradiation control device executes a predetermined control process after the process of the image processing device; a perspective image acquiring unit that acquires the perspective images streamed out from the perspective image generating device and acquires from the rotation mechanism a rotation angle of the perspective image generating device at the time when the perspective image generating device generated the perspective image; a treatment plan acquisition unit that acquires, from a treatment planning device, the treatment plan including a CT image of the subject in a specific respiratory phase and an isocenter coordinate for specifying an irradiation position of the radiation beam on the subject in the specific respiratory phase; a DRR image generating unit that generates DRR images of the subject for each predetermined angle around the axis based on the CT images and the isocenter coordinates acquired by the treatment plan acquisition unit; a positional deviation amount calculation unit that calculates a positional deviation amount, which is a deviation amount of a respiratory position of the diaphragm of the subject in the fluoroscopic image when a position of the diaphragm of the subject in the DRR image is used as a reference, by using the fluoroscopic image and the DRR image at the same rotation angle; a permission determination unit that permits irradiation of the radiation beam from the radiation beam source to the subject when the amount of positional deviation is equal to or less than a predetermined value; having The positional deviation amount calculation unit generating a plurality of shifted images by shifting the fluoroscopic image in a cranial-caudal direction of the subject within a predetermined range at a predetermined interval; Calculating a normalized correlation coefficient between each of the generated shift images and the DRR image; a processing device that determines, as the positional deviation amount, a shift amount in the cranio-caudal direction with respect to the perspective image of a shift image that has a maximum normalized correlation coefficient among the calculated normalized correlation coefficients.

39. 1. An irradiation control method for controlling irradiation of a radiation beam from a radiation beam source of a radiation irradiation device to a subject, based on a treatment plan for radiation therapy for the subject and a fluoroscopic image of the subject, comprising: The subject is placed on a placement section, the fluoroscopic image is generated by a fluoroscopic image generating device when the subject is placed on the placement unit so as to be located on an axis of the placement unit; The arrangement portion is rotatable about the axis by a rotation mechanism, The irradiation control method includes: a treatment plan acquisition step of acquiring the treatment plan including a CT image of the subject at a specific respiratory phase and an isocenter coordinate for specifying an irradiation position of the radiation beam on the subject at the specific respiratory phase; a DRR image generating step of generating DRR images of the subject for each predetermined angle around the axis based on the acquired CT images and the isocenter coordinates; a perspective image acquiring step of acquiring the perspective image streamed out from the perspective image generating device and acquiring, from the rotation mechanism, a rotation angle of the placement unit when the perspective image generating device generated the perspective image; a positional deviation amount calculation step of calculating a positional deviation amount, which is an amount of deviation of a respiratory position of the diaphragm of the subject in the fluoroscopic image when a position of the diaphragm of the subject in the DRR image is used as a reference, using the fluoroscopic image and the DRR image at the same rotation angle; an irradiation permission step of permitting irradiation of the radiation beam from the radiation beam source to the subject when the amount of positional deviation is equal to or less than a predetermined value; having In the positional deviation calculation step, generating a plurality of shifted images by shifting the fluoroscopic image in a cranial-caudal direction of the subject within a predetermined range at a predetermined interval; Calculating a normalized correlation coefficient between each of the generated shift images and the DRR image; an amount of shift in the cranio-caudal direction with respect to the fluoroscopic image of a shift image that has a maximum normalized correlation coefficient among the plurality of normalized correlation coefficients calculated is determined as the amount of positional deviation.

40. 1. An irradiation control method for controlling irradiation of a radiation beam from a radiation beam source of a radiation irradiation device to a subject, based on a treatment plan for radiation therapy for the subject and a fluoroscopic image of the subject, comprising: The subject is placed on the axis of a gantry in a placement section, the fluoroscopic image is generated by a fluoroscopic image generating device disposed on the gantry when the subject is disposed on the axis in the placement unit; the radiation beam source is disposed in the gantry, and irradiates the radiation beam toward the subject when the subject is disposed on the axis line at the positioning unit; the fluoroscopic image generating device and the radiation beam source are rotatable about the axis by a rotation mechanism; The irradiation control method includes: a treatment plan acquisition step of acquiring the treatment plan including a CT image of the subject at a specific respiratory phase and an isocenter coordinate for specifying an irradiation position of the radiation beam on the subject at the specific respiratory phase; a DRR image generating step of generating DRR images of the subject for each predetermined angle around the axis based on the acquired CT images and the isocenter coordinates; a perspective image acquiring step of acquiring the perspective image streamed out from the perspective image generating device and acquiring, from the rotation mechanism, a rotation angle of the perspective image generating device at the time when the perspective image generating device generated the perspective image; a positional deviation amount calculation step of calculating a positional deviation amount, which is an amount of deviation of a respiratory position of the diaphragm of the subject in the fluoroscopic image when a position of the diaphragm of the subject in the DRR image is used as a reference, using the fluoroscopic image and the DRR image at the same rotation angle; an irradiation permission step of permitting irradiation of the radiation beam from the radiation beam source to the subject when the amount of positional deviation is equal to or less than a predetermined value; having In the positional deviation calculation step, generating a plurality of shifted images by shifting the fluoroscopic image in a cranial-caudal direction of the subject within a predetermined range at a predetermined interval; Calculating a normalized correlation coefficient between each of the generated shift images and the DRR image; an amount of shift in the cranio-caudal direction with respect to the fluoroscopic image of a shift image that has a maximum normalized correlation coefficient among the plurality of normalized correlation coefficients calculated is determined as the amount of positional deviation.

41. 1. An image processing method for performing a predetermined image processing on a fluoroscopic image of a subject generated by a fluoroscopic image generating device based on a treatment plan for radiation therapy for the subject in a specific respiratory phase, the method comprising: the treatment plan includes diaphragm information, which is three-dimensional information of the diaphragm of the subject in the specific respiratory phase; The image processing method includes: a projection image generating step of generating a projection image obtained by projecting the diaphragm onto a projection surface of the perspective image using the diaphragm information; a contour line extraction step of extracting a contour line of the diaphragm from the projection image; a display processing step of superimposing and displaying the contour line on the perspective image; An image processing method comprising the steps of:

42. 1. A processing method for performing a predetermined image processing on a fluoroscopic image of a subject generated by a fluoroscopic image generating device based on a treatment plan for radiation therapy for a subject in a specific respiratory phase, and then controlling irradiation of a radiation beam from a radiation beam source of a radiation irradiation device to the subject based on the treatment plan and the fluoroscopic image, comprising: the treatment plan includes diaphragm information, which is three-dimensional information of the diaphragm of the subject in the specific respiratory phase; The subject is placed on a placement section, the fluoroscopic image is generated by a fluoroscopic image generating device when the subject is placed on the placement unit so as to be located on an axis of the placement unit; The arrangement portion is rotatable about the axis by a rotation mechanism, The processing method includes: a projection image generating step of generating a projection image obtained by projecting the diaphragm onto a projection surface of the perspective image using the diaphragm information; a contour line extraction step of extracting a contour line of the diaphragm from the projection image; a display processing step of superimposing and displaying the contour line on the perspective image; a treatment plan acquisition step of acquiring the treatment plan including a CT image of the subject in the specific respiratory phase and an isocenter coordinate for specifying an irradiation position of the radiation beam of the subject in the specific respiratory phase after the display processing step is executed; a DRR image generating step of generating DRR images of the subject for each predetermined angle around the axis based on the acquired CT images and the isocenter coordinates; a perspective image acquiring step of acquiring the perspective image streamed out from the perspective image generating device and acquiring, from the rotation mechanism, a rotation angle of the placement unit when the perspective image generating device generated the perspective image; a positional deviation amount calculation step of calculating a positional deviation amount, which is an amount of deviation of a respiratory position of the diaphragm of the subject in the fluoroscopic image when a position of the diaphragm of the subject in the DRR image is used as a reference, using the fluoroscopic image and the DRR image at the same rotation angle; an irradiation permission step of permitting irradiation of the radiation beam from the radiation beam source to the subject when the amount of positional deviation is equal to or less than a predetermined value; having In the positional deviation calculation step, generating a plurality of shifted images by shifting the fluoroscopic image in a cranial-caudal direction of the subject within a predetermined range at a predetermined interval; Calculating a normalized correlation coefficient between each of the generated shift images and the DRR image; a shift amount in the cranio-caudal direction with respect to the first perspective image of a shift image that has a maximum normalized correlation coefficient among the plurality of normalized correlation coefficients calculated is determined as the positional deviation amount.

43. 1. A processing method for performing a predetermined image processing on a fluoroscopic image of a subject generated by a fluoroscopic image generating device based on a treatment plan for radiation therapy for a subject in a specific respiratory phase, and then controlling irradiation of a radiation beam from a radiation beam source of a radiation irradiation device to the subject based on the treatment plan and the fluoroscopic image, comprising: the treatment plan includes diaphragm information, which is three-dimensional information of the diaphragm of the subject in the specific respiratory phase; The subject is placed on the axis of a gantry in a placement section, the fluoroscopic image is generated by a fluoroscopic image generating device disposed on the gantry when the subject is disposed on the axis in the placement unit; the radiation beam source is disposed in the gantry, and irradiates the radiation beam toward the subject when the subject is disposed on the axis line at the positioning unit; the fluoroscopic image generating device and the radiation beam source are rotatable about the axis by a rotation mechanism; The processing method includes: a projection image generating step of generating a projection image obtained by projecting the diaphragm onto a projection surface of the perspective image using the diaphragm information; a contour line extraction step of extracting a contour line of the diaphragm from the projection image; a display processing step of superimposing and displaying the contour line on the perspective image; a treatment plan acquisition step of acquiring the treatment plan including a CT image in the specific respiratory phase and an isocenter coordinate for specifying an irradiation position of the radiation beam on the subject in the specific respiratory phase after the display processing step is executed; a DRR image generating step of generating DRR images of the subject for each predetermined angle around the axis based on the acquired CT images and the isocenter coordinates; a perspective image acquiring step of acquiring the perspective image streamed out from the perspective image generating device and acquiring, from the rotation mechanism, a rotation angle of the perspective image generating device at the time when the perspective image generating device generated the perspective image; a positional deviation amount calculation step of calculating a positional deviation amount, which is an amount of deviation of a respiratory position of the diaphragm of the subject in the fluoroscopic image when a position of the diaphragm of the subject in the DRR image is used as a reference, using the fluoroscopic image and the DRR image at the same rotation angle; an irradiation permission step of permitting irradiation of the radiation beam from the radiation beam source to the subject when the amount of positional deviation is equal to or less than a predetermined value; having In the positional deviation calculation step, generating a plurality of shifted images by shifting the fluoroscopic image in a cranial-caudal direction of the subject within a predetermined range at a predetermined interval; Calculating a normalized correlation coefficient between each of the generated shift images and the DRR image; a shift amount in the cranio-caudal direction with respect to the first perspective image of a shift image that has a maximum normalized correlation coefficient among the plurality of normalized correlation coefficients calculated is determined as the positional deviation amount.

44. A program for causing a computer to execute at least one of the irradiation control method according to claim 39 or 40, the image processing method according to claim 41, and the processing method according to claim 42 or 43.

45. A storage medium for storing the program according to claim 44.

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