Position collation device, method, and program

Abstract

To improve positioning accuracy of an irradiation position of a radioactive ray to a patient in a radiotherapy.SOLUTION: A position collation device includes an acquisition unit, a calculation unit, and a display control unit. The acquisition unit acquires a plan image for a radiotherapy plan and an image of a radiotherapy execution day for positioning an object person in the radiotherapy on the same object person. The calculation unit calculates a first index, a second index, and / or a third index on the basis of an object cross section of the plan image and / or the image of the radiotherapy execution day for each combination of a gantry rotation angle and a bed iso rotation angle set in the radiotherapy plan. The first index is related to a separation degree between a beam path and an OAR region, the second index is related to an inclusion degree of a tumor region by the beam path, and the third index is related to a coincidence degree between the plan image and the image of the radiotherapy execution day in the object cross section. The display control unit displays the first index, the second index, and / or the third index in a display device.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The embodiments disclosed in this specification and the drawings relate to a position matching device, a method, and a program. [Background technology]

[0002] In radiation therapy, there is an IGRT (Image Guided Radiotherapy) system that checks the radiation irradiation position on the patient before radiation irradiation. The irradiation position is checked by registering a 3D same-day image taken on the day of radiation therapy with a 3D planning image used in the radiation therapy plan. The results of 3D image registration tend to differ depending on the algorithm. In non-coplanar therapy, in which radiation is irradiated while changing the gantry rotation angle for each of multiple couch iso-rotation angles, it is particularly difficult to ensure registration accuracy in cross sections of areas where organs are prone to movement, such as the trunk. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2020-138099 A [Patent Document 2] JP 2019-010508 A [Patent Document 3] JP 2013-146381 A Summary of the Invention [Problem to be solved by the invention]

[0004] One of the problems to be solved by the embodiments disclosed in this specification and the drawings is to improve the accuracy of aligning the radiation irradiation position on a patient in radiation therapy. However, the problems to be solved by the embodiments disclosed in this specification and the drawings are not limited to the above problem. Problems corresponding to the effects of each configuration shown in the embodiments described later can also be positioned as other problems. [Means for solving the problem]

[0005] The position matching device according to the embodiment includes an acquisition unit, a calculation unit, and a display control unit. The acquisition unit acquires first three-dimensional human body shape information for a radiation therapy plan and second three-dimensional human body shape information for alignment of the subject in radiation therapy, both of which are related to the same subject. The calculation unit calculates a first index, a second index, and / or a third index based on a target cross section of the first three-dimensional human body shape information and / or the second three-dimensional human body shape information for each combination of a gantry rotation angle and a bed iso-rotation angle set in the radiation therapy plan. The first index relates to a degree of separation between a beam path and an OAR region, the second index relates to a degree of inclusion of a tumor region by the beam path, and the third index relates to a degree of agreement between the first three-dimensional human body shape information and the second three-dimensional human body shape information in the target cross section. The display control unit displays the first index, the second index, and / or the third index on a display device. [Brief description of the drawings]

[0006] [Figure 1] FIG. 1 is a diagram illustrating an example of the configuration of a radiation therapy system. [Diagram 2] FIG. 2 is a diagram showing the configuration of the position matching device. [Diagram 3] FIG. 3 is a diagram illustrating the gantry rotation angle. [Figure 4] FIG. 4 is a diagram illustrating the couch iso-rotation angle. [Diagram 5] FIG. 5 is a diagram illustrating a processing procedure of the image matching process performed by the position matching device. [Figure 6] FIG. 6 is a diagram showing a schematic diagram of three-dimensional registration using two types of image matching algorithms. [Figure 7] FIG. 7 is a diagram illustrating an example of the positional relationship between the three orthogonal cross-sectional images. [Figure 8] FIG. 8 is a diagram showing an example of a display screen for three-dimensional registration by tumor shape matching. [Figure 9]FIG. 9 is a diagram showing an example of a display screen for three-dimensional alignment by rectangular parallelepiped matching. [Figure 10] FIG. 10 is a diagram showing the degree of separation in a cross-sectional image. [Figure 11] FIG. 11 is a diagram showing the coverage in a cross-sectional image. [Figure 12] FIG. 12 is a diagram showing the image matching degree in the cross-sectional images. [Figure 13] FIG. 13 is a diagram showing an example of a color map representing a two-dimensional angular distribution of image matching degrees. [Figure 14] FIG. 14 is a diagram showing an example of a display screen relating to the processing from steps S8 to S10. [Figure 15] FIG. 15 is a diagram illustrating a color map according to the first modification. [Figure 16] FIG. 16 is a diagram illustrating an example of a color map according to the second modification. [Figure 17] FIG. 17 is a diagram showing an example of a display screen of the statistical values ​​of the image coincidence degree at each bed iso-rotation angle according to the third modification. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0007] Hereinafter, a position matching device, method, and program according to the present embodiment will be described in detail with reference to the drawings.

[0008] Fig. 1 is a diagram showing an example of the configuration of a radiation therapy system 100. As shown in Fig. 1, the radiation therapy system 100 includes a planning image capturing device 1, a radiation therapy planning device 3, a current-day image capturing device 5, a position matching device 7, and a radiation therapy device 9. The planning image capturing device 1, the radiation therapy planning device 3, the current-day image capturing device 5, the position matching device 7, and the radiation therapy device 9 can communicate with each other via a network.

[0009] The planning image capturing device 1 is a medical imaging device that performs medical imaging on a treatment target (patient) to generate medical images to be used for treatment planning. Hereinafter, a medical image to be used for treatment planning is called a planning image. The planning image is assumed to be three-dimensional image data composed of voxels arranged in a three-dimensional shape. The planning image capturing device 1 may be any medical imaging device capable of generating a planning image. Examples of medical imaging devices include an X-ray computed tomography device, a magnetic resonance imaging device, a cone beam CT device, and a nuclear medicine diagnostic device. The planning image is transmitted to a radiation therapy planning device 3.

[0010] The radiation therapy planning device 3 is a computer that creates a treatment plan for a patient to be treated. The radiation therapy planning device 3 creates a treatment plan based on a planning image. Specifically, various volumes, irradiation conditions, and dose distribution are created as the treatment plan. As the various volumes, a tumor region to be treated by radiation, an OAR (Organ At Risk) region that is a normal tissue region with high radiation sensitivity, an irradiation region that is the irradiation position of radiation, etc. are defined. As irradiation conditions, the irradiation angle, number of portals, irradiation intensity, etc. of radiation are determined. The dose distribution is a spatial distribution of the planned value of the administered dose of radiation, and is managed and provided by being superimposed on the planning image. The treatment plan is transmitted to the radiation therapy device 9.

[0011] The same-day image capturing device 5 is a medical imaging device that performs medical imaging on the patient to be treated on the day of radiation therapy to generate a medical image. Hereinafter, the medical image generated by the same-day image capturing device 5 is called the same-day image. More specifically, the day of radiation therapy means the timing immediately before or during radiation irradiation by the radiation therapy device 9. The same-day image is used for alignment with the planning image, etc. It is three-dimensional image data composed of voxels arranged in a three-dimensional shape. The same-day image capturing device 5 may be any medical imaging device capable of generating a planning image, like the planning image capturing device 1. The same-day image capturing device 5 may also be incorporated into the radiation therapy device 9. The same-day image is transmitted to the radiation therapy device 9.

[0012] The position matching device 7 is a computer for aligning the treatment plan and the image on the day. As an example, the position matching device 7 is installed in a radiation treatment room. By adjusting the position of the patient by grasping the amount of deviation between the treatment plan and the image on the day through the alignment, the irradiation position determined in the treatment plan can be spatially reproduced.

[0013] The radiotherapy device 9 is a device that irradiates radiation to a patient for radiotherapy. The radiation used can be appropriately selected from X-rays, electron beams, proton beams, heavy particle beams, alpha rays, beta rays, gamma rays, neutron beams, etc. The radiotherapy device 9 irradiates radiation according to a treatment plan created by the radiotherapy planning device 3, and shrinks or eliminates a tumor in the patient's body. As an example, the radiotherapy device 9 according to this embodiment is assumed to be a linear accelerator device that irradiates high-energy X-rays.

[0014] Fig. 2 is a diagram showing the configuration of the position matching device 7. As shown in Fig. 4, the position matching device 7 has a processing circuit 71, a storage device 73, a display device 75, an input device 77, and a communication device 79. Data communication between the processing circuit 71, the storage device 73, the display device 75, the input device 77, and the communication device 79 is performed via a bus.

[0015] The processing circuit 71 has a processor. The processor starts a position matching program installed in the storage device 73 or the like, thereby realizing an acquisition function 711, a three-dimensional position matching function 712, a matching index calculation function 713, a two-dimensional position matching function 714, and a display control function 715. Each of the functions 711 to 715 is not limited to being realized by a single processing circuit 71. A processing circuit may be configured by combining a plurality of independent processors, and each processor may execute a program to realize each of the functions 711 to 715.

[0016] By implementing the acquisition function 711, the processing circuit 71 acquires various information. Specifically, the processing circuit 71 acquires, for the same subject, first three-dimensional human body shape information for a radiation therapy plan and second three-dimensional human body shape information for positioning the subject in radiation therapy. The three-dimensional human body shape information means three-dimensional information representing the shape of the inside and / or the surface of the human body. The three-dimensional human body shape information is three-dimensional medical image data of the subject collected by a medical imaging device or three-dimensional body surface data of the subject collected by a three-dimensional shape measuring device. The three-dimensional shape measuring device is a measuring device (three-dimensional scanner) that optically scans the measurement target to measure the shape of the measurement target.

[0017] By implementing the three-dimensional positioning function 712, the processing circuitry 71 three-dimensionally aligns the first three-dimensional human body shape information and the second three-dimensional human body shape information. The processing circuitry 71 may calculate the amount of deviation between the first three-dimensional human body shape information and the second three-dimensional human body shape information in the process of the three-dimensional positioning, and calculate the amount of movement (shift amount) of the bed of the radiotherapy device 9 corresponding to the amount of deviation.

[0018] By implementing the matching index calculation function 713, the processing circuit 71 calculates the first index, the second index, and / or the third index based on the target cross section of the first three-dimensional human body shape information and / or the second three-dimensional human body shape information for each combination of the gantry rotation angle and the couch iso-rotation angle set in the radiation therapy plan. The first index relates to the degree of separation between the beam path and the OAR region. The second index relates to the degree of inclusion of the tumor region by the beam path. The third index relates to the degree of agreement between the first three-dimensional human body shape information and the second three-dimensional human body shape information in the target cross section. The first index, the second index, and the third index are indexes for evaluating the position matching between the first three-dimensional human body shape information and the second three-dimensional human body shape information, and are collectively referred to as matching indexes. The processing circuit 71 may calculate the first index, the second index, and / or the third index based on the first three-dimensional human body shape information and / or the second three-dimensional human body shape information after three-dimensional alignment by the three-dimensional alignment function 712.

[0019] By implementing the two-dimensional registration function 714, the processing circuitry 71 two-dimensionally aligns the first and second three-dimensional human body shape information in the target cross section. In the process of the two-dimensional registration, the processing circuitry 71 may calculate a deviation amount in the target cross section between the first and second three-dimensional human body shape information after the three-dimensional registration, and calculate a movement amount (shift amount) of the bed of the radiotherapy device 9 corresponding to the deviation amount.

[0020] By implementing the display control function 715, the processing circuitry 71 displays various information on the display device 75. For example, the processing circuitry 71 displays the first index, the second index, and / or the third index calculated by the matching index calculation function 713 on the display device. At this time, the processing circuitry 71 displays the first index, the second index, and / or the third index for each combination of the gantry rotation angle and the bed iso-rotation angle.

[0021] The storage device 73 is a storage device such as a ROM (Read Only Memory), a RAM (Random Access Memory), an HDD (Hard Disk Drive), an SSD (Solid State Drive), or an integrated circuit storage device that stores various information. In addition to the above storage devices, the storage device 73 may be a drive device that reads and writes various information between a portable storage medium such as a CD (Compact Disc), a DVD (Digital Versatile Disc), or a flash memory, or a semiconductor memory element. The storage device 73 may be in another computer connected to the position matching device 7 via a network.

[0022] The input device 77 receives various input operations from the user, converts the received input operations into electrical signals, and outputs the electrical signals to the processing circuit 71. Specifically, the input device 77 is connected to input devices such as a mouse, a keyboard, a trackball, a switch, a button, a joystick, a touchpad, and a touch panel display. The input device 77 may be an audio input device that uses an audio signal from an input device such as a microphone that collects audio. The input device 77 may be a non-contact input circuit that uses an optical sensor. The input device 77 outputs an electrical signal corresponding to an input operation to the input device to the processing circuit 71. In addition, the input device connected to the input device 77 may be an input device provided in another computer connected via a network or the like.

[0023] The communication device 79 is an interface for communicating information among the planning image capturing device 1, the radiation therapy planning device 3, the on-the-day image capturing device 5, and the radiation therapy device 9 included in the radiation therapy system 100.

[0024] The display device 75 displays various information in accordance with a display control function 715 of the processing circuit 71. A liquid crystal display (LCD), a cathode ray tube (CRT) display, an organic electroluminescence display (OELD), a plasma display, or any other display may be appropriately used as the display device 75. The display device 75 may also be a projector.

[0025] An example of the operation of the radiation therapy system 100 according to this embodiment will be described in detail below.

[0026] In the following description, the three-dimensional human body shape information is assumed to be three-dimensional medical image data of the subject collected by a medical image capturing device. In this case, the first three-dimensional human body shape information is a planned image collected by a planned image capturing device 1, and the second three-dimensional human body shape information is a current image collected by a current image capturing device 5.

[0027] The method of radiation therapy by the radiation therapy device 9 is assumed to be non-coplanar therapy in which radiation is irradiated while changing the gantry rotation angle for each of a plurality of bed iso-rotation angles. In non-coplanar therapy, radiation is irradiated while changing the gantry rotation angle discretely or continuously from a first angle to a second angle for each of a plurality of discretely set bed iso-rotation angles. For this reason, a radiation therapy plan for non-coplanar therapy specifies a combination of the gantry rotation angle and bed iso-rotation angle at which radiation is irradiated.

[0028] FIG. 3 is a diagram illustrating the gantry rotation angle θR. As shown in FIG. 3, the radiotherapy device 9 has a gantry 91 installed in a radiotherapy room. The gantry 91 supports an irradiation head 92 rotatably around a rotation axis AR. The irradiation head 92 is equipped with, for example, an acceleration tube that accelerates electrons generated by an electron gun or the like, and a metal target on which the electrons accelerated by the acceleration tube collide. Radiation is generated by the electrons colliding with the metal target. Here, an axis parallel to the rotation axis AR is defined as the Z axis, an axis horizontally intersecting the Z axis is defined as the X axis, and an axis vertically intersecting the Z axis is defined as the Y axis.

[0029] The gantry 91 and the irradiation head 92 are designed so that the rotation axis AR intersects with the isocenter, which is a fixed point on the central axis of the radiation beam. The angle of the irradiation head 92 around the rotation axis AR by the gantry 91 is defined as the gantry rotation angle θR. As an example, the gantry rotation angle θR is set to 0 degrees when the irradiation head 92 is at the uppermost position, and the gantry rotation angle θR increases as the irradiation head 92 rotates clockwise with 0 degrees as the reference.

[0030] FIG. 4 is a diagram illustrating the bed iso-rotation angle θB. As shown in FIG. 4, the radiotherapy device 9 has a bed 93 installed in a radiotherapy room. A patient is placed on the bed 93. When the bed 93 is rotated around a vertical axis (Y-axis) passing through an isocenter IC, the opening angle between the long axis AB of the bed 93 and the rotation axis AR in the horizontal direction (X-axis direction) is defined as the bed iso-rotation angle θB. As an example, the bed iso-rotation angle θB is set to 0 degrees when the long axis AB overlaps with the rotation axis AR in the horizontal direction, and the bed iso-rotation angle θB increases as the long axis AB opens in the +X direction to the rotation axis AR.

[0031] Next, the image matching process by the position matching device 7 will be described with reference to Fig. 5. Fig. 5 is a diagram illustrating a processing procedure of the image matching process by the position matching device 7. The image matching process is performed immediately before radiation therapy on the day of radiation therapy, or during or between radiation irradiation.

[0032] Prior to the image matching process, before the time of radiation therapy, a planning image of the patient is captured by the planning image capture device 1, and a treatment plan is created based on the planning image by the radiation therapy planning device 3. The planning image and the treatment plan are transferred to the position matching device 7 and stored in the storage device 73. On the day of radiation therapy, a same-day image of the patient is captured by the same-day image capture device 5 for patient setup alignment. The same-day image represents the patient's current position and internal anatomy. The same-day image is transferred to the position matching device 7 and stored in the storage device 73.

[0033] 5, first, the processing circuitry 71 acquires a planning image and a current image by implementing the acquisition function 711 (step S1). In step S1, the processing circuitry 71 acquires a planning image and a current image of the same patient from the storage device 73.

[0034] When step S2 is performed, the processing circuitry 71 performs three-dimensional registration between the planning image acquired in step S1 and the current image by implementing the three-dimensional registration function 712, using a predetermined algorithm (hereinafter, image matching algorithm) (step S2). The image matching algorithm is characterized by the object to be registered, the spatial range of the object to be registered, and / or the degree of freedom of deformation of the registration. The object to be registered may be an anatomical portion such as a bone or a tumor, or an instrument such as a seed source, a coil, or a fixture. The spatial range of the object to be registered may be the entire image, a predefined shape range such as a rectangular parallelepiped, a cylinder, or a sphere, or an arbitrary shape range such as a mask. The degree of freedom of deformation of the registration may be rigid transformation or non-rigid transformation. The rigid transformation is a transformation including rotation and / or translation, and the non-rigid transformation is a transformation including rotation, translation, enlargement, and / or reduction. The image matching algorithm to be used can be specified by any method.

[0035] FIG. 6 is a diagram showing a schematic diagram of three-dimensional registration by two kinds of image matching algorithms. As shown in FIG. 6, a planning image I1 and a current image I2 of the same part of the same subject are acquired. The planning image I1 includes a tumor region I11, an OAR region I12, and a bone region I13, and the current image I2 also includes a tumor region I21, an OAR region I22, and a bone region I23. The processing circuit 71 aligns the planning image I1 and the current image I2 so that the structures I11, I12, and I13 in the planning image I1 match the structures I21, I22, and I23 in the current image I2 within the spatial range of the three-dimensional registration target. Rigid body transformation is assumed as the transformation method for the registration. Therefore, it is not expected that the structures I11, I12, and I13 in the planning image I1 and the structures I21, I22, and I23 in the current image I2 will all match perfectly. The processing circuitry 71 calculates the amount of misalignment according to the amount of deformation of the structures I11, I12, and I13 and the structures I21, I22, and I23 due to the alignment, and calculates the amount of shift of the bed 93 according to the amount of misalignment.

[0036] Here, the difference in registration accuracy caused by the difference in image matching algorithm will be described. As shown in FIG. 6, one image matching algorithm uses wide ranges I14 and I24 including tumor regions I11 and I21, OAR regions I12 and I22, and bone regions I13 and I23 as the spatial range of the registration target, and the other image matching algorithm uses narrow ranges I15 and I25 including tumor regions I11 and I21 as the spatial range of the registration target. The three-dimensional registration in the wide ranges I14 and I24 (wide-range registration) is performed so that the total amount of deviation of the tumor regions I11 and I21, OAR regions I12 and I22, and bone regions I13 and I23 included in the wide ranges I14 and I24 is minimized, and the three-dimensional registration in the narrow ranges I15 and I25 (narrow-range registration) is performed so that the amount of deviation of the tumor regions I11 and I21 included in the narrow ranges I15 and I25 is minimized. Therefore, differences in image matching algorithms result in differences in alignment accuracy.

[0037] For example, in the superimposed image I3 using wide-area registration, the positional deviation between the structures I31, I32, and I33 is smaller within the wide-area range I34 than in the superimposed image I4 using narrow-area registration. On the other hand, in the superimposed image I4, the tumor region I41 completely matches within the narrow-area range I45, but the positional deviation between the other structures I42 and I43 outside the narrow-area range I45 is larger than in the superimposed image I3. Also, in the superimposed image I3, the beam path I36 is outside the OAR region I32, but part of the tumor region I31 is outside the beam path I36, while in the superimposed image I4, the beam path I46 is superimposed on part of the OAR region I42, but the entire tumor region I41 is within the beam path I36.

[0038] Therefore, various conditions of the image matching algorithm should be set according to the purpose of the alignment, etc. In step S2, it is sufficient that the three-dimensional alignment is performed by at least one image matching algorithm.

[0039] When step S2 is performed, the processing circuitry 71 identifies a combination of gantry rotation angles and bed iso-rotation angles to be calculated by implementing the matching index calculation function 713 (step S3). As described above, the radiation therapy according to this embodiment is non-coplanar therapy. The radiation therapy planning device 3 sets a plurality of discrete bed iso-rotation angles and an angle range for changing the gantry rotation angle for each bed iso-rotation angle. As an example, it is assumed that the bed iso-rotation angles and the angle ranges of the bed iso-rotation angles are set as follows. Note that CW means clockwise.

[0040] Bed iso-rotation angle = 300 degrees: Gantry rotation angle 270 degrees to 90 degrees (CW) Bed iso-rotation angle = 330 degrees: Gantry rotation angle 270 degrees to 90 degrees (CW) Bed iso-rotation angle = 0 degrees: Gantry rotation angle 270 degrees to 90 degrees (CW) Bed iso-rotation angle = 30 degrees: Gantry rotation angle 270 degrees to 90 degrees (CW) Bed iso-rotation angle = 60 degrees: Gantry rotation angle 270 degrees to 90 degrees (CW)

[0041] The processing circuitry 71 identifies one combination from among the combinations of the planned bed iso-rotation angles and gantry rotation angles as a combination to be calculated. The following steps S4 and S5 are performed for the combination to be calculated. Since steps S4 and S5 are eventually performed for all combinations, the combination to be calculated may be identified in order from among the combinations of the planned bed iso-rotation angles and gantry rotation angles.

[0042] When step S3 is performed, the processing circuitry 71 generates three orthogonal slice images at the isocenter based on the beam's eye view at the gantry rotation angle by implementing the matching index calculation function 713 (step S4). In step S4, the processing circuitry 71 generates three orthogonal slice images based on a superimposed image of the planned image and the current image aligned in step S2. The three orthogonal slice images are an example of slice images related to the target slice.

[0043] Fig. 7 is a diagram illustrating an example of the positional relationship of three orthogonal cross-sectional images. As shown in Fig. 7, a beam path is set at a gantry rotation angle in a combination to be calculated. The beam path passes through an isocenter IC. A cross section that intersects with the isocenter IC and is orthogonal to the beam path is set as a beam's eye view cross section CS1. Two cross sections CS2 and CS3 that intersect with the isocenter IC and are orthogonal to the beam's eye view cross section CS1 are also set. The three orthogonal cross-sectional images corresponding to the three orthogonal cross sections are displayed in an arbitrary layout on a display device 75 by a processing circuit 71.

[0044] Fig. 8 is a diagram showing an example of a display screen I5 for 3D registration by tumor shape matching. Tumor shape matching is 3D registration using a tumor as the anatomical site to be registered. A beams-eye view cross-sectional image I51 and other cross-sectional images I52 and I53 are displayed on the display screen I5. The tumor region is highlighted in each of the images I51, I52, and I53.

[0045] 9 is a diagram showing an example of a display screen I6 for 3D alignment by rectangular parallelepiped matching. Rectangular parallelepiped matching is 3D alignment in which a rectangular parallelepiped is a preset shape range to be aligned. The image matching screen I6 displays a beams-eye view cross-sectional image I63 and other cross-sectional images I61 and I62. The tumor region I64 and OAR region I65 are highlighted in each of the images I61, I62, and I63.

[0046] When step S4 is performed, the processing circuitry 71 calculates a matching index by implementing the matching index calculation function 713 (step S5). In step S5, the processing circuitry 71 calculates a matching index for each of the three orthogonal cross-sectional images generated in step S4. As the matching index, at least one of a first index (hereinafter, separation degree) related to the degree of separation between the beam path and the OAR region in each cross-sectional image, a second index (hereinafter, containment degree) related to the degree of inclusion between the beam path and the tumor region, and a third index (hereinafter, image coincidence degree) related to the degree of agreement between the planning image and the current image in the three orthogonal cross-sectional images is calculated. The type of the matching index to be calculated can be arbitrarily selected by a user or the like via an input device 77 or the like. The matching index is stored in the storage device 73 in association with the couch iso-rotation angle, the gantry rotation angle, and the identifier of the cross-sectional image.

[0047] FIG. 10 is a diagram showing the separation degree D1 in the cross-sectional image I7. As the cross-sectional image I7, any image among the three orthogonal cross-sectional images generated in step S4 is illustrated. The cross-sectional image I7 includes a tumor region I71, an OAR region I72, a bone region I73, and the like. Also, the cross-sectional image I7 highlights the beam path I74 set in the treatment plan. The separation degree D1 evaluates the degree of separation between the beam path I74 and the OAR region I72 in the cross-sectional image I7. Specifically, as the separation degree D1, an index that takes into account the effect of the OAR on radiation on the distance between the beam path I74 and the OAR region I72 may be calculated. For example, the separation degree D1 may be expressed as a percentage based on the distance between beam path I74 and OAR region I72, with "0%" indicating that OAR region I72 overlaps or is close to beam path I74, thereby predicting that unacceptable damage will be caused to the OAR, and "100%" indicating that OAR region I72 is far from beam path I74, thereby predicting that no damage will be caused to the OAR.

[0048] Alternatively, the separation degree D1 may simply be represented as the distance between the beam path I74 and the OAR region I72. In this case, when the beam path I74 partially or completely overlaps with the OAR region I72, the separation degree D1 may be calculated as "0" or may be calculated as the diameter or area of ​​the overlapping region between the beam path I74 and the OAR region I72.

[0049] In the treatment plan, it is expected that the beam path is set to include the tumor area and avoid the OAR area. In addition, radiation should be avoided from irradiating the OAR area during radiation therapy. The degree of separation makes it possible to evaluate the patient position shift between the planning image capture and the on-the-day image capture, in other words, the accuracy of image matching between the planning image and the on-the-day image.

[0050] FIG. 11 is a diagram showing the coverage degree D2 in the cross-sectional image I8. As the cross-sectional image I8, any image among the three orthogonal cross-sectional images generated in step S4 is illustrated. The cross-sectional image I8 includes a tumor region I81, an OAR region I82, a bone region I83, and the like. In addition, the cross-sectional image I8 has a beam path I84 set in the treatment plan emphasized. The coverage degree D2 evaluates the coverage degree between the beam path I84 and the tumor region I81 in the cross-sectional image I8. Specifically, as the coverage degree D2, the area ratio or diameter ratio of the non-overlapping region in the overlapping region between the beam path I84 and the tumor region I81 may be calculated. Alternatively, as the coverage degree D2, the area ratio or diameter ratio of the overlapping region or non-overlapping region in the entire tumor region between the beam path I84 and the tumor region I81 may be calculated.

[0051] In the treatment plan, it is expected that the beam path is set to include the tumor region and avoid the OAR region. In addition, during radiation therapy, it is desirable to irradiate radiation only to the tumor region. The coverage makes it possible to evaluate the patient position shift between the time of taking the planning image and the time of taking the image on the day, in other words, the accuracy of image matching between the planning image and the image on the day. It is also assumed that radiation is irradiated only to a part of the tumor region. In this case, the overlapping degree may be calculated based on the irradiation target area of ​​the tumor region.

[0052] FIG. 12 is a diagram showing the image matching degree D3 in the cross-sectional image I9. As the cross-sectional image I9, any image among the three orthogonal cross-sectional images generated in step S4 is illustrated. The cross-sectional image I9 includes a tumor region I91, an OAR region I92, and a bone region I93 derived from the planned image and the current image. The image matching degree D3 evaluates the degree of matching between the planned image and the current image in the cross-section of the cross-sectional image I9. Specifically, it may be calculated based on the cumulative value of the difference in pixel values ​​of the same pixel between the planned image and the current image, the percentage of the cumulative value, the number of pixels whose pixel values ​​do not match or match between the planned image and the current image, the percentage of the number, etc.

[0053] The degree of image coincidence makes it possible to evaluate the positional deviation of the patient between when the planning image is captured and when the image is captured on the day, in other words, the accuracy of image matching between the planning image and the image on the day.

[0054] When step S5 is performed, the processing circuit 71 determines whether or not the matching index has been calculated for all planned angle combinations by implementing the matching index calculation function 713 (step S6). If it is determined that the matching index has not been calculated for all angle combinations, the processing circuit 71 repeats steps S3 to S5 for the angle combinations for which the matching index has not been calculated, and calculates the matching index for all angle combinations.

[0055] Then, when it is determined in step S6 that the matching indexes have been calculated for all angle combinations (step S6: YES), the processing circuit 71 displays the matching indexes calculated in step S5 in a color map by implementing the display control function 715 (step S7). In step S7, the processing circuit 71 reads out a coordinate system defined by the gantry rotation angle and the bed iso-rotation angle. As an example, a two-dimensional orthogonal coordinate system is used in which the gantry rotation angle is defined as the first axis and the bed iso-rotation angle is defined as the second axis. The processing circuit 71 plots the matching indexes for each angle combination in the read out coordinate system with a color value according to the value. As a result, a color map is generated that represents a two-dimensional angle distribution of the matching indexes. The color map is generated for some or all of the matching indexes calculated in step S5. The type of matching index for which the color map is to be generated can be arbitrarily selected by the user or the like via the input device 77.

[0056] FIG. 13 is a diagram showing an example of a color map I10 representing a two-dimensional angular distribution of image coincidence. FIG. 13 shows a color map I10 of the separation degree as an example. The color map I10 is a map in which the separation degree is plotted with a color value according to its value in a two-dimensional orthogonal coordinate system in which the gantry rotation angle is defined on the vertical axis and the bed isocenter angle is defined on the horizontal axis. The color map I10 has color bars I101 to I105 for each bed isorotation angle. The color bar I101 corresponds to a bed isorotation angle of "300 degrees", the color bar I102 corresponds to a bed isorotation angle of "330 degrees", the color bar I103 corresponds to a bed isorotation angle of "0 degrees", the color bar I104 corresponds to a bed isorotation angle of "30 degrees", and the color bar I105 corresponds to a bed isorotation angle of "60 degrees". Each of the color bars I101 to I105 represents a one-dimensional angular distribution of the separation degree having the gantry rotation angle as one axis. For example, the processing circuit 71 may display the portion corresponding to the angle combination with a poor degree of separation in a dark color and the portion corresponding to the angle combination with a good degree of separation in a light color. Specifically, it is possible to associate the degree of separation with a color value as follows.

[0057] When the distance is 100% (far from the safe zone), the RGB value is "0xFFFF00" (yellow). When the separation rate is 0% (entering the danger zone), the RGB value is "0xFFFFFF" (black).

[0058] By associating the degree of separation with a color value as described above, the user can visually grasp whether the angle combination has a good or bad degree of separation. The processing circuitry 71 may highlight the portion corresponding to the angle combination whose degree of separation is equal to or less than a threshold value with a warning color (e.g., red) or may add a specific pattern such as an arrow. The processing circuitry 71 may generate and display a color map separately for each of the three orthogonal cross-sectional images, or may generate and display a color map that indicates the statistical value of the matching index of the three orthogonal cross-sectional images.

[0059] 13, the separation degree is used as an example of the matching index, but the color map can be displayed in the same way for other matching indexes (including degree of coverage or image matching degree). Therefore, the user can visually grasp whether the angle combination of the matching index is good or bad by observing the color map.

[0060] When step S7 is performed, the processing circuitry 71 identifies an angle combination that is worth paying attention to (hereinafter, an angle combination of interest) by implementing the two-dimensional positioning function 714 (step S8). In step S8, the processing circuitry 71 identifies an angle combination of interest based on a matching index for each angle combination. Specifically, the processing circuitry 71 identifies a specific combination of angle combinations whose separation degree, inclusion degree, and / or image matching degree are below a standard as the angle combination of interest. The angle combination of interest may be determined according to a user instruction, or may be determined automatically based on a threshold value or the like.

[0061] When step S8 is performed, the processing circuitry 71 performs two-dimensional registration between the planning image and the current image at the cross section of interest corresponding to the combination of angles of interest identified in step S8 by implementing the two-dimensional registration function 714 (step S9). In step S9, the processing circuitry 71 displays a cross-sectional image of the cross section of interest by implementing the display control function 715. Then, the processing circuitry 71 performs two-dimensional registration between the planning image and the current image at the cross section of interest according to a user operation on the displayed cross-sectional image. Note that the processing circuitry 71 may perform two-dimensional registration according to an automatic algorithm rather than a user operation.

[0062] After step S9 is performed, the processing circuitry 71 displays the two-dimensional alignment result obtained in step S9 (step S10) by implementing the display control function 715. In step S10, the processing circuitry 71 displays the two-dimensional alignment result on the display device 75 in a predetermined layout.

[0063] Here, the process from step S8 to S10 will be specifically described with reference to FIG. 14. FIG. 14 is a diagram showing an example of a display screen I11 related to the process from step S8 to S10. As shown in FIG. 14, a color map I111 of the matching index is displayed on the display screen I11. As in FIG. 13, a color map based on the separation degree is displayed as the color map I111. The processing circuit 71 displays the color map I111 so that any angle combination can be selected. The user observes the color map I111 and determines the attention angle combination to be the target of the two-dimensional alignment. For example, the user determines an angle combination whose separation degree does not reach a standard as the attention angle combination, and selects the attention angle combination via a pointer I115 such as a mouse. As a result, the attention angle combination is specified by the processing circuit 71 (S8).

[0064] When the angle combination of interest is specified, the processing circuitry 71 generates three orthogonal cross-sectional images I112, I113, and I114 related to the beam's eye view corresponding to the gantry rotation angle of the angle combination of interest based on the superimposed image, and displays the generated three orthogonal cross-sectional images I112, I113, and I114 on the display screen I11. Various structures such as a tumor region I117 and an OAR region I118 and a beam path I119 are displayed on the three orthogonal cross-sectional images I112, I113, and I114. In addition, various treatment plans such as dose distribution may be displayed on the three orthogonal cross-sectional images I112, I113, and I114.

[0065] In Figure 14, the planning image and the current image are 3D registered by the tumor matching algorithm. The tumor region I117 is included in the beam path I119, but a part of the OAR region I118 overlaps with the beam path I119. This is assumed to be the cause of the poor separation. The cause of the separation value can be visually confirmed by displaying the orthogonal three cross-sectional images corresponding to the attention angle combination selected by the user.

[0066] The processing circuitry 71 performs two-dimensional registration on the three orthogonal cross-sectional images I112, I113, and I114 (S9). It is assumed that the two-dimensional registration is performed manually by a user via an input device 77. For example, when the separation degree is used as the matching index, it is preferable to perform two-dimensional registration between the planning image and the current image so that the beam path I119 does not overlap the OAR region I118. Note that the two-dimensional registration may be performed automatically using an existing algorithm instead of using a manual method.

[0067] The processing circuitry 71 may change the image matching algorithm for three-dimensional alignment and repeat steps S3 to S10 when the accuracy of the two-dimensional alignment is not desirable or when it is desired to improve the accuracy. In this case, the processing circuitry 71 calculates the degree of separation, the degree of coverage, and / or the degree of image agreement based on the target cross-section of the planned image and the current image aligned three-dimensionally by the first image matching algorithm, and when the degree of separation, the degree of coverage, and / or the degree of image agreement is below a criterion, calculates the degree of separation, the degree of coverage, and / or the degree of image agreement based on the target cross-section of the planned image and the current image aligned by a second image matching algorithm different from the first image matching algorithm. The criterion can be arbitrarily set according to the value of the matching index requested by the user. The processing circuitry 71 may display the degree of separation, the degree of coverage, and / or the degree of image agreement between the first image matching algorithm and the second image matching algorithm by a color map or the like. This makes it easy to grasp the difference in the matching index due to the difference in the image matching algorithm. The processing circuitry 71 may also display cross-sectional images of the same three orthogonal cross-sections of the first image matching algorithm and the second image matching algorithm. In each cross-sectional image, in order to understand the positional relationship between the two images due to differences in image matching algorithms, it is advisable to display the tumor region, OAR region, bone region, beam path, dose distribution, etc. in an emphasized manner.

[0068] When the planned image and the current image are aligned, the processing circuitry 71 calculates the final amount of deviation between the planned image and the current image, and converts the calculated amount of deviation into a shift amount of the bed. The processing circuitry 71 displays the calculated amount of shift in the display field I110 of the display screen I11. This allows the user to confirm the accurate amount of shift after the two-dimensional alignment. After that, the user can move the bed or the patient according to the shift amount to bring the patient's body surface and internal structure on the day of treatment closer to those at the time of capturing the planned image.

[0069] This completes the image matching process according to the present embodiment. Note that step S2 shown in Fig. 5 can be omitted as appropriate. That is, the matching index may be calculated based on the planning image and / or the current image that have not been subjected to three-dimensional registration.

[0070] (Variation 1) In the above embodiment, the color map represents one of the matching indices, i.e., the degree of separation, the degree of coverage, and the degree of image matching. However, the present embodiment is not limited to this. The processing circuitry 71 may generate and display a color map representing two-dimensional angle distributions of two or three (all) of the degrees of separation, the degree of coverage, and the degree of image matching.

[0071] FIG. 15 is a diagram illustrating a color map I12 according to the first modification. The color map I12 represents, as an example, a two-dimensional angle distribution of all matching indices (separation, inclusion, and image matching). In the color map I12, a color bar (number 1) representing the separation, a color bar (number 2) representing the inclusion, and a color bar (number 3) representing the image matching are arranged in parallel for each bed iso-rotation angle. As an example, each color bar is displayed with a different color value, and each color bar is displayed with a brightness value according to the value of the corresponding matching index. This makes it possible to distinguish the value of each matching index by light and dark while color-coding the types of matching indices.

[0072] According to the first modification, the angle distribution of multiple types of matching markers can be confirmed with one color map. In addition, by arranging the color bars of each matching marker for each bed iso-rotation angle, the values ​​of the matching markers for each angle combination can be confirmed side by side.

[0073] (Variation 2) By implementing the display control function 715, the processing circuit 71 according to the second variant example may emphasize an area in a color map of the indices to be displayed, among the degree of separation, the degree of inclusion, and the degree of image consistency, where a matching index other than the indices to be displayed, among the degree of separation, the degree of inclusion, and the degree of image consistency, falls below a standard.

[0074] FIG. 16 is a diagram showing an example of a color map I3 according to the second modification. The color map I13 represents a two-dimensional angle distribution of only the image matching degree. The color map I13 is displayed with a color value according to the image matching degree. The processing circuit 71 identifies an angle combination whose separation degree or inclusion degree is below a reference value. The reference value can be set to an arbitrary value such as a lower limit value of an allowable range of the separation degree or inclusion degree. The processing circuit 71 highlights an angle region I131 of the color map I3 corresponding to the identified angle combination with a color value or the like. The angle region I131 clearly indicates an angle range in which the separation degree or inclusion degree is not allowable. This allows the user to visually grasp an angle combination whose separation degree or inclusion degree is below a reference value in the color map related to the image matching degree.

[0075] According to the second modification, in the color map showing the two-dimensional angle distribution of the matching index to be generated, it is possible to visually grasp the angle combination in which the matching index different from the matching index to be generated falls below the standard. This makes it possible to express the result of the acceptability determination based on the different matching index in the color map related to the matching index to be generated.

[0076] (Variation 3) The processing circuitry 71 according to the third modification may calculate a statistical value of the matching index over the angle range of the gantry rotation angle for each bed iso-rotation angle, and display the statistical value of the matching index for each bed iso-rotation angle. The statistical value may be appropriately selected from an average value, a median value, a minimum value, a maximum value, a standard deviation, etc. according to a user's preference, etc. The statistical value may be displayed for two-dimensional alignment in step S9, for example. Furthermore, the matching index for which the statistical value is calculated may be appropriately selected from the degree of separation, the degree of coverage, and the degree of image agreement.

[0077] Fig. 17 is a diagram showing an example of a display screen I13 of the statistical values ​​of the image matching degree at each bed iso-rotation angle. As shown in Fig. 17, the image matching degree is used as a matching index, and the average value, minimum value, and standard deviation are used as the statistical values. In the display screen I13, the average value, minimum value, and standard deviation are displayed as numerical values ​​for each of the bed iso-rotation angles of 300 degrees, 330 degrees, 0 degrees, 30 degrees, and 60 degrees. This allows the user to grasp the statistical values ​​of the image matching degree according to the bed iso-rotation angle in numerical values.

[0078] When the average value and the minimum value are below the threshold value or the standard deviation exceeds the threshold value, the processing circuitry 71 may align the planned image and the current image according to the adjustment of the planned image and the current image by the user so that the average value and the minimum value exceed the threshold value and the standard deviation falls below the threshold value. At this time, the processing circuitry 71 may display the three orthogonal cross sections corresponding to the angle combination with the worst statistical value of interest on the display device 75, and the user may adjust the planned image and the current image on the three orthogonal cross sections. The processing circuitry 71 may also change the image matching algorithm according to the user's selection.

[0079] According to the third modification, it becomes possible to grasp the collation index for each bed iso-rotation angle in numerical terms using statistical values.

[0080] (Variation 4) In the above embodiment, the radiation therapy is a non-coplanar therapy in which radiation is irradiated while changing the gantry rotation angle from the first angle to the second angle for each of a plurality of bed iso-rotation angles. However, this embodiment is not limited to this. The radiation therapy according to the fourth modification does not need to change the bed iso-rotation angle. That is, this embodiment is also applicable to a radiation therapy in which radiation is irradiated while changing the gantry rotation angle from the first angle to the second angle for a single bed iso-rotation angle. In this case, the color map represents a one-dimensional angle distribution in which the matching index is plotted with a color value according to its value in a one-dimensional coordinate system with the gantry rotation angle for a single bed iso-rotation angle as a single axis.

[0081] (Variation 5) In the above embodiment, the bed iso-rotation angle, which is the angle between the rotation axis AR of the gantry 91 and the long axis AB of the bed 93, is changed by moving the bed. However, this embodiment is not limited to this. The radiotherapy apparatus 9 according to the fifth modification may change the bed iso-rotation angle by rotating the gantry 91 around the Y axis.

[0082] (Variation 6) In the above embodiment, a medical image is used as the three-dimensional human body shape information. However, this embodiment is not limited to this. The position matching device 7 according to the sixth modification may use three-dimensional body surface data collected by a three-dimensional shape measuring device as the three-dimensional human body shape information. This enables surface image guided radiotherapy (SIGRT) using body surface information. In this case, the processing circuitry 71 replaces the medical image with the three-dimensional body surface data and executes the above various processes. For example, the processing circuitry 71 performs position matching by two-dimensional alignment on the target cross section between the three-dimensional body surface data collected at the time of treatment planning and the three-dimensional body surface data collected on the day of radiation treatment.

[0083] (Summary) As in some of the above embodiments, the position matching device 7 according to this embodiment includes a processing circuit 71. The processing circuit 71 acquires the first three-dimensional human body shape information for a radiation therapy plan and the second three-dimensional human body shape information for the alignment of the subject in radiation therapy, both of which are related to the same subject. The processing circuit 71 calculates a first index, a second index, and / or a third index based on the target cross section of the first three-dimensional human body shape information and / or the second three-dimensional human body shape information for each combination of the gantry rotation angle and the bed iso-rotation angle set in the radiation therapy plan. The first index relates to the degree of separation between the beam path and the OAR region. The second index relates to the degree of inclusion of the tumor region by the beam path. The third index relates to the degree of agreement between the first three-dimensional human body shape information and the second three-dimensional human body shape information in the target cross section. The processing circuit 71 displays the first index, the second index, and / or the third index on the display device 75.

[0084] According to the above configuration, by displaying the first index, the second index, and / or the third index for each combination of the gantry rotation angle and the bed iso-rotation angle set in the radiation therapy plan, it is possible to perform strict two-dimensional alignment between the first three-dimensional human body shape information and the second three-dimensional human body shape information, taking into account the first index, the second index, and / or the third index. By performing strict two-dimensional alignment, radiation can be irradiated with a minimum deviation from the irradiation position determined in the treatment plan. Therefore, according to the present embodiment, improvement of irradiation accuracy is expected. In addition, since the deviation from the irradiation position determined in the treatment plan can be minimized, it is also possible to reduce the margin for the tumor area, and to improve the irradiation accuracy of boost irradiation, which additionally irradiates radiation to a part of the tumor area. In non-coplanar therapy, radiation is irradiated from various directions to one three-dimensional irradiation area, so that the deviation from the irradiation position determined in the treatment plan tends to be larger than in normal radiation therapy. However, according to this embodiment, it is expected that the irradiation accuracy can be improved even in non-coplanar treatment, and accurate positioning can be achieved even in cross sections of regions where organs are prone to movement, such as the trunk.

[0085] According to at least one of the embodiments described above, it is possible to improve the accuracy of aligning the radiation irradiation position on a patient in radiation therapy.

[0086] The term "processor" used in the above description means a circuit such as a CPU, a GPU, an application specific integrated circuit (ASIC), a programmable logic device (e.g., a simple programmable logic device (SPLD), a complex programmable logic device (CPLD), and a field programmable gate array (FPGA)). The processor realizes a function by reading and executing a program stored in a memory circuit. Instead of storing a program in a memory circuit, the program may be directly built into the circuit of the processor. In this case, the processor realizes a function by reading and executing a program built into the circuit. On the other hand, when the processor is, for example, an ASIC, instead of storing the program in a memory circuit, the function is directly built into the circuit of the processor as a logic circuit. Note that each processor in this embodiment is not limited to being configured as a single circuit for each processor, but may be configured as a single processor by combining multiple independent circuits. Furthermore, the multiple components in FIG. 1 and FIG. 2 may be integrated into a single processor to realize the function.

[0087] Although some embodiments have been described, these embodiments are presented as examples and are not intended to limit the scope of the invention. These embodiments can be implemented in various other forms, and various omissions, substitutions, modifications, and combinations of embodiments can be made without departing from the spirit of the invention. These embodiments and their modifications are included in the scope of the invention and its equivalents as described in the claims, as well as in the scope and spirit of the invention. [Explanation of symbols]

[0088] 1 Planning image capture device 3. Radiation therapy planning device 5. Same-day imaging device 7 Position matching device 9 Radiation therapy equipment 71 Processing circuit 73 Storage device 75 Display equipment 77 Input Devices 79 Communication Equipment 100 Radiation Therapy System 711 Acquisition Function 712 3D positioning function 713 Matching index calculation function 714 2D positioning function 715 Display control function

Claims

1. an acquisition unit that acquires, for the same subject, first three-dimensional human body shape information for a radiation therapy plan and second three-dimensional human body shape information for positioning the subject in radiation therapy; a calculation unit for calculating a first index, a second index, and / or a third index based on a target cross section of the first three-dimensional body shape information and / or the second three-dimensional body shape information for each combination of a gantry rotation angle and a couch iso-rotation angle set in the radiation therapy plan, wherein the first index relates to a degree of separation between a beam path and an OAR region, the second index relates to a degree of inclusion of a tumor region by the beam path, and the third index relates to a degree of agreement between the first three-dimensional body shape information and the second three-dimensional body shape information in the target cross section; a display control unit that displays the first index, the second index, and / or the third index on a display device; A position matching device comprising:

2. The position matching device according to claim 1 , wherein the display control unit displays the first index, the second index, and / or the third index for each of the combinations.

3. 3. The position matching device according to claim 2, wherein the display control unit displays a color map in which the first index, the second index, and / or the third index are plotted with color values ​​according to their values ​​in a coordinate system defined by the gantry rotation angle and the bed iso-rotation angle.

4. The position matching device according to claim 3 , wherein the display control unit displays a cross-sectional image of the target cross-section corresponding to a specific combination in which the first index, the second index, and / or the third index are below a reference value among the combinations.

5. 4. The position matching device according to claim 3, wherein the display control unit emphasizes, in the color map of an index to be displayed among the first index, the second index, and the third index, an angle region in which an index other than the index to be displayed among the first index, the second index, and / or the third index falls below a reference angle.

6. 4. The position matching device according to claim 3, wherein the display control unit displays, for each of the bed iso-rotation angles, statistical values ​​of the first index, the second index, and / or the third index across an angular range of gantry rotation angles in numerical form.

7. 2. The position matching device according to claim 1, further comprising a two-dimensional registration unit that two-dimensionally aligns the first three-dimensional human body shape information and the second three-dimensional human body shape information on the target cross section.

8. The position matching device according to claim 1 , wherein the target cross section includes a beam's eye view cross section intersecting an isocenter.

9. a three-dimensional alignment unit that three-dimensionally aligns the first three-dimensional human body shape information and the second three-dimensional human body shape information, the calculation unit calculates the first index, the second index, and / or the third index based on the first three-dimensional human body shape information and / or the second three-dimensional human body shape information after three-dimensional alignment by the three-dimensional alignment unit; The position matching device according to claim 1 .

10. 10. The position matching device according to claim 9, wherein an algorithm for the three-dimensional registration performed by the three-dimensional registration unit is characterized by an object to be registered, a spatial range to be registered, and / or a degree of freedom of deformation for registration.

11. The calculation unit is calculating the first index, the second index, and / or the third index based on the target cross section of the first three-dimensional human body shape information and the second three-dimensional human body shape information three-dimensionally aligned by a first algorithm; When the first index, the second index, and / or the third index are below a reference, the first index, the second index, and / or the third index are calculated based on the target cross section of the first three-dimensional human body shape information and the second three-dimensional human body shape information aligned by a second algorithm different from the first algorithm. The position matching device according to claim 9.

12. the gantry rotation angle is a rotation angle around a central axis of a gantry provided in a radiotherapy device, The bed iso-rotation angle is an opening angle between the long axis of a bed provided in the radiation therapy apparatus and the central axis in the horizontal direction. The position matching device according to claim 1 .

13. 2. The position matching device according to claim 1, wherein the radiation therapy is a non-coplanar therapy in which radiation is irradiated while changing the gantry rotation angle from a first angle to a second angle for each of a plurality of bed iso-rotation angles.

14. The position matching device of claim 1, wherein the first three-dimensional human body shape information and the second three-dimensional human body shape information are three-dimensional medical image data of the subject collected by a medical imaging device or three-dimensional body surface data of the subject collected by a three-dimensional shape measuring device.

15. acquiring, for the same subject, first three-dimensional body shape information for a radiation therapy plan and second three-dimensional body shape information for positioning the subject in radiation therapy; calculating a first index, a second index, and / or a third index based on a target cross section of the first three-dimensional body shape information and / or the second three-dimensional body shape information for each combination of a gantry rotation angle and a couch iso-rotation angle set in the radiation therapy plan, wherein the first index relates to a degree of separation between a beam path and an OAR region, the second index relates to a degree of inclusion of a tumor region by the beam path, and the third index relates to a degree of agreement between the first three-dimensional body shape information and the second three-dimensional body shape information in the target cross section; displaying the first indicator, the second indicator, and / or the third indicator on a display device; A position matching method comprising:

16. On the computer, A function of acquiring, for the same subject, first three-dimensional body shape information for a radiation therapy plan and second three-dimensional body shape information for positioning the subject in radiation therapy; a function for calculating a first index, a second index, and / or a third index based on a target section of the first three-dimensional body shape information and / or the second three-dimensional body shape information for each combination of a gantry rotation angle and a bed iso-rotation angle set in the radiation therapy plan, wherein the first index relates to a degree of separation between a beam path and an OAR region, the second index relates to a degree of inclusion of a tumor region by the beam path, and the third index relates to a degree of agreement between the first three-dimensional body shape information and the second three-dimensional body shape information in the target section, a function of displaying the first indicator, the second indicator, and / or the third indicator on a display device; A location matching program that makes this possible.

Images