X-ray imaging system

Abstract

This X-ray imaging system (100) is provided with a dose calculation processing unit (70) and a display unit (4). The dose calculation processing unit (70) calculates a dose in each of a plurality of angle regions that are divided at predetermined angle intervals of imaging unit angles on the basis of the distribution of doses on the surface of a virtual model (Pa) and imaging unit angles assigned to the surface of the virtual model (Pa). The display unit (4) is configured so as to display an angular dose image (42) capable of distinguish the level of the calculated dose in each of the plurality of angle regions.

Description

[Technical Field]

[0001] The present invention relates to an X-ray imaging system that displays the X-ray dose. Mu Regarding. [Background technology]

[0002] Conventionally, there has been known an X-ray imaging device that displays the dose of X-rays, such as that disclosed in U.S. Patent Application Publication No. 2011 / 0317815.

[0003] The X-ray imaging device described in the above-mentioned U.S. Patent Application Publication No. 2011 / 0317815 displays a three-dimensional model that visualizes the dose of X-rays irradiated onto the surface of a patient. Specifically, this X-ray imaging device calculates the dose of X-rays irradiated onto the surface of the patient on the three-dimensional model of the patient. The magnitude of the calculated dose is then visualized and displayed on the displayed three-dimensional model. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] US Patent Application Publication No. 2011 / 0317815 Summary of the Invention [Problem to be solved by the invention]

[0005] Conventionally, X-ray imaging devices such as those described in U.S. Patent Application Publication No. 2011 / 0317815 are used in interventional radiology (IVR). When performing treatment while irradiating X-rays in interventional radiology, it is necessary to perform treatment while changing the angle of the imaging unit according to the increase in the dose in order to prevent the dose (skin dose) from becoming locally high on the body surface of the subject (patient). However, when the magnitude of the dose is displayed on a three-dimensional model as in U.S. Patent Application Publication No. 2011 / 0317815, even if the dose displayed on the three-dimensional model is confirmed, it is difficult to specifically determine an appropriate imaging unit angle (an angle with a relatively low dose) to avoid positions with a relatively high dose. Therefore, it is desirable to easily select an appropriate imaging unit angle with a relatively low dose in order to prevent the dose from becoming locally high on the body surface of the subject.

[0006] The present invention has been made to solve the above-mentioned problems, and one object of the present invention is to provide an X-ray imaging system that can easily select an appropriate imaging unit angle that provides a relatively small dose in order to prevent the dose from becoming locally large on the body surface of a subject. M The purpose is to provide. [Means for solving the problem]

[0008] This invention oneThe X-ray imaging system in this aspect includes an X-ray irradiation unit having an X-ray source that irradiates X-rays onto a subject lying on a tabletop, an imaging unit including an X-ray detection unit that detects the X-rays irradiated from the X-ray irradiation unit, a movement mechanism that changes the imaging unit angle, which is the angle of the imaging unit, a dose calculation processing unit that calculates the dose of X-rays irradiated onto the subject, and a display unit that displays the dose of X-rays calculated by the dose calculation processing unit, wherein the dose calculation processing unit includes a model dose calculation unit that calculates the distribution of doses on the surface of a three-dimensional virtual model representing the subject lying on the tabletop based on the dose of X-rays irradiated onto the subject by X-ray irradiation from the imaging unit, an angle association unit that associates the imaging unit angle with the surface of the virtual model based on the imaging unit angle and the position on the surface of the virtual model where the X-rays are irradiated, and a display unit that displays the dose of the virtual model calculated by the model dose calculation unit. and an angular dose calculation unit that calculates a dose in each of a plurality of angular regions partitioned at predetermined angular intervals of the imaging unit angle based on a dose distribution on the surface of the virtual model and the imaging unit angle that has been associated with the surface of the virtual model by the angle association unit, wherein the display unit is configured to display an angular dose image in which the plurality of angular regions are arranged at predetermined angular intervals and in which the magnitude of the dose in each of the plurality of angular regions calculated by the angular dose calculation unit can be distinguished, and the display unit further includes an operation unit that accepts an input operation by an operator, and the movement mechanism is configured to change the imaging unit angle so that X-rays are irradiated to the selected angular region when an operation to select one of the plurality of angular regions in the angular dose image in which the plurality of angular regions are arranged at the predetermined angular intervals is accepted by the operation unit. 。 [Effects of the Invention]

[0009] the above one The X-ray imaging system in this aspect calculates a dose in each of a plurality of angular regions partitioned at predetermined angular intervals of the imaging unit angle based on the calculated dose distribution on the surface of the virtual model and the imaging unit angle associated with the surface of the virtual model. oneThe X-ray imaging system according to the aspect displays an angular dose image that allows the magnitude of the dose in each of a plurality of angular regions to be distinguished. This allows an operator (operator) such as a doctor to visually check the displayed angular dose image and confirm the magnitude of the dose in each of a plurality of angular regions divided at predetermined angular intervals of the imaging unit angle, thereby easily determining an imaging unit angle that provides a relatively low dose. As a result, an appropriate imaging unit angle that provides a relatively low dose can be easily selected to prevent a localized increase in the dose on the body surface of the subject. [Brief explanation of the drawings]

[0010] [Figure 1] FIG. 1 is a schematic diagram for explaining the configuration of an X-ray imaging system according to the present embodiment. [Figure 2] 1 is a block diagram showing the overall configuration of an X-ray imaging system according to the present embodiment. [Figure 3] FIG. 2 is a diagram for explaining a display on a monitor according to the present embodiment. [Figure 4] FIG. 2 is a block diagram for explaining the functional configuration of a dose calculation processing unit according to the present embodiment. [Figure 5] 10A and 10B are diagrams for explaining how to obtain the positional relationship between the tabletop and the imaging unit. [Figure 6] FIG. 10 is a diagram for explaining calculation of a dose distribution in a virtual model. [Figure 7] 10A and 10B are diagrams for explaining the correspondence between the surface of the virtual model and the angle of the imaging unit. [Figure 8] 10A and 10B are diagrams for explaining an angular dose image and a color scale image. [Figure 9] 10A and 10B are diagrams for explaining updating of an angular dose image when the tabletop is moved in the up and down direction of the subject; [Figure 10] 10A and 10B are diagrams for explaining updating of an angular dose image when the tabletop is moved in the left-right direction of the subject; [Figure 11] 10A and 10B are diagrams for explaining updating of an angular dose image when the tabletop is moved in the vertical direction. [Figure 12] 10A and 10B are diagrams for explaining updating of an angular dose image when the angle interval is changed. [Figure 13] FIG. 10 is a diagram showing an example of a display of recommended angle regions. [Figure 14] FIG. 10 is a diagram showing an example of a timeline display. [Figure 15] FIG. 10 is a diagram showing an example of a display for selecting the angle of the imaging unit on a touch panel. [Figure 16] FIG. 10 is a diagram showing an angle dose image displayed on a touch panel. [Figure 17] FIG. 10 is a diagram showing an example of a three-dimensional image display. [Figure 18] FIG. 10 is a flowchart illustrating a control process of the dose display method according to the present embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0011] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, specific embodiments of the present invention will be described with reference to the accompanying drawings.

[0012] (X-ray imaging system configuration) The configuration of an X-ray imaging system 100 according to one embodiment of the present invention will be described with reference to FIGS.

[0013] As shown in FIG. 1, the X-ray imaging system 100 is an apparatus that captures an X-ray image 41 (see FIG. 3) of the inside of a subject P, such as a human body, by irradiating X-rays from outside the subject P. An operator such as a doctor using the X-ray imaging system 100 can perform various treatments (interventional radiology (IVR)) by inserting a treatment instrument such as a catheter into the blood vessels of the subject P (for example, the blood vessels of the heart of the subject P) while visually checking the X-ray image 41 of the subject P. Note that in this specification, the term "operator" is not limited to an operator who treats the subject P, but also includes an operator who simply operates the X-ray imaging system 100 without being directly involved in the treatment of the subject P. In other words, the operator is an example of the "operator" in the claims.

[0014] 1 and 2, the X-ray imaging system 100 includes a tabletop 1, an imaging unit 2, a moving mechanism 3, a monitor 4, a touch panel 5, and an operation unit 6. The monitor 4 is an example of a "display unit" in the claims. The touch panel 5 is an example of a "touch panel" in the claims, and also serves as an example of an "operation unit" in the claims.

[0015] (Configuration of each part of the X-ray imaging system) 1 and 2, the top board 1 is configured as an examination table on which the subject P lies (places) when X-ray imaging is performed. The top board 1 is supported by a top board moving unit 31 (described later) so as to be movable in the horizontal and vertical directions. The top board 1 is also configured so that the angle of the placement surface can be changed by the top board moving unit 31 (described later) while the subject P is lying down.

[0016] As shown in FIGS. 1 and 2, the imaging unit 2 captures an X-ray image 41 (see FIG. 3) of the subject P. The imaging unit 2 also includes an X-ray irradiator 21 and an X-ray detector 22. The X-ray irradiator 21 and the X-ray detector 22 are arranged to face each other across the tabletop 1 on which the subject P lies. The X-ray irradiator 21 and the X-ray detector 22 are movably supported by a support unit 32, which will be described later.

[0017] The X-ray irradiator 21 has an X-ray source 21a and a collimator 21b. The X-ray source 21a irradiates X-rays onto the subject P lying on the tabletop 1. The X-ray source 21a is connected to a high-voltage generator (not shown) and is an X-ray tube that generates X-rays when a high voltage is applied, and irradiates the subject P with the generated X-rays. The X-ray source 21a is arranged with the X-ray emission direction facing the detection surface of the X-ray detector 22. The collimator 21b is configured to adjust the irradiation field of the X-rays irradiated by the X-ray source 21a. The X-ray irradiator 21 generates X-rays in accordance with preset imaging conditions such as tube voltage, tube current, and time interval between X-ray irradiation under the control of a control device 101 (described later).

[0018] The X-ray detection unit 22 detects the X-rays irradiated from the X-ray irradiation unit 21. Then, the X-ray detection unit 22 outputs a detection signal according to the detected X-ray intensity. The X-ray detection unit 22 is configured by, for example, an FPD (Flat Panel Detector). The X-ray detection unit 22 is connected to a control device 101, which will be described later.

[0019] The movement mechanism 3 moves at least one of the tabletop 1 and the imaging unit 2. Specifically, the movement mechanism 3 changes the relative positional relationship between the tabletop 1 and the imaging unit 2, thereby changing the position of the body surface of the subject P to be irradiated with X-rays. Specifically, the movement mechanism 3 includes a tabletop movement unit 31 that moves the tabletop 1 and a support unit 32 that changes the imaging unit angle of the imaging unit 2. The tabletop movement unit 31 is configured to be able to move the tabletop 1 in the horizontal direction (a direction parallel to the horizontal plane) and the vertical direction. The tabletop movement unit 31 also changes the angle of the tabletop 1. The support unit 32 is disposed on the ceiling C and supports the X-ray irradiator 21 and the X-ray detector 22 so that they face each other across the tabletop 1 on which the subject P lies. The support unit 32 also supports the imaging unit 2 so that the position and angle (imaging unit angle) can be changed. The support unit 32 also supports the distance between the X-ray irradiator 21 and the X-ray detector 22 so that the distance can be changed. The movement mechanism 3 includes, for example, a servo motor controlled by a control device 101, which will be described later.

[0020] For example, when cardiac catheterization is performed by interventional radiology (IVR), the treatment is performed while continuously acquiring moving fluoroscopic images (X-ray images 41) of the heart and changing the X-ray irradiation angle (image capture unit angle) to suppress a local increase in radiation dose on the body surface (skin) of the subject P. In this embodiment, the movement mechanism 3 is configured to change the image capture unit angle, which is the angle of the image capture unit 2, through control processing by the control device 101, which will be described later. The image capture unit angle is the angle in the direction in which the X-ray irradiator 21 and the X-ray detector 22 face each other. Furthermore, the image capture unit 2 changes the image capture unit angle so that the X-ray detector 22 moves in the left and right directions of the subject P (LAO) (left anterior oblique) and the right anterior oblique (RAO) and in the up and down directions (head and leg directions) of the subject P (CRA) (cranial and CAU).

[0021] 3, monitor 4 displays an X-ray image 41, an angular dose image 42, a color scale image 43, a maximum value display 44, a timeline display 45 (see FIG. 14), and a three-dimensional image 46 under the control of a control device 101 (described later). Monitor 4 includes a display monitor, which is a device that displays video signals of still images or moving images output from a device such as a computer. Details of the display on monitor 4 will be described later.

[0022] 1 and 2, the touch panel 5 receives an input operation from an operator (a surgeon or an operator) to operate the X-ray imaging system 100. The touch panel 5 is configured to transmit an input signal based on the received input operation to a control device 101 and a dose calculation device 102, which will be described later. Specifically, the touch panel 5 is a tablet PC having a calculation device such as a CPU (Central Processing Unit) and a storage unit such as a flash memory, and is configured to be able to communicate with the control device 101 and the dose calculation device 102, which will be described later. The touch panel 5 is also configured to display a display related to the selection of the imaging unit angle. The display on the touch panel 5 will be described in detail later.

[0023] Like the touch panel 5, the operation unit 6 accepts input operations by an operator (surgeon or operator). The operation unit 6 includes, for example, a pointing device such as a keyboard or a mouse. The operation unit 6 also includes an irradiation button that accepts an input operation to irradiate X-rays, and a movement operation button that accepts an input operation to move the tabletop 1 and the imaging unit 2. The operation unit 6 is also configured to transmit an input signal based on the accepted input operation to the control device 101, which will be described later.

[0024] That is, the operation of each unit of the X-ray imaging system 100 is controlled based on input operations on the touch panel 5 and the operation unit 6. For example, the touch panel 5 and the operation unit 6 accept an input operation to select (change) an imaging unit angle at which X-ray imaging is performed from among a plurality of imaging unit angles. The touch panel 5 and the operation unit 6 also accept an input operation to change the display on the monitor 4. The touch panel 5 and the operation unit 6 also accept an input operation to irradiate X-rays.

[0025] As shown in FIG. 2, the X-ray imaging system 100 of this embodiment includes a control device 101, a dose calculation device 102, and a three-dimensional image generation device 103.

[0026] The control device 101 is a computer (arithmetic device) including a CPU, a GPU (Graphics Processing Unit), a ROM (Read Only Memory), and a RAM (Random Access Memory). The control device 101 also includes storage devices such as an HDD (Hard Disk Drive) and an SSD (Solid State Drive). The control device 101 controls the operation of the X-ray imaging system 100 based on an operation by an operator. The control device 101 also controls the display on the monitor 4. That is, the control device 101 controls the imaging unit 2 to control X-ray imaging and generate an X-ray image 41. Specifically, the control device 101 controls the operation of the X-ray irradiator 21 to irradiate X-rays onto the subject P. The control device 101 also acquires detection signals output from the X-ray detector 22 and generates the X-ray image 41 based on the acquired detection signals.

[0027] 3, the X-ray image 41 is an image showing the inside of the subject P based on a detection signal of X-rays that have passed through the subject P. The X-ray images 41 are continuously acquired so that an operator can observe the state inside the body of the subject P in real time. The X-ray images 41 are configured to be displayed on the monitor 4 as moving images.

[0028] Furthermore, the control device 101 changes the relative position and angle of the tabletop 1 and the imaging unit 2 by controlling the operation of the movement mechanism 3 based on input operations on the touch panel 5 and the operation unit 6. In other words, the control device 101 is configured to control the operation of the movement mechanism 3 to set the imaging unit angle at which X-ray imaging is to be performed.

[0029] The dose calculation device 102 has a dose calculation processing unit 70, which is a computer (arithmetic device) including a CPU, a GPU, a ROM, a RAM, etc. The dose calculation device 102 also has a storage device such as an HDD or SSD that stores a predetermined program for operating the dose calculation processing unit 70. The storage device also stores a virtual model Pa, which will be described later, and various setting values ​​(parameters), etc. The storage device also stores a history of the dose irradiated to the subject P. In this embodiment, the dose calculation processing unit 70 is configured to calculate the dose of X-rays irradiated to the subject P.

[0030] The three-dimensional image generation device 103 is a computer (arithmetic device) including a CPU, a GPU, a ROM, a RAM, etc., similar to the control device 101 and the dose calculation device 102. The three-dimensional image generation device 103 generates a three-dimensional image 46. The generation of the three-dimensional image 46 will be described in detail later.

[0031] In the X-ray imaging system 100, the control device 101, the dose calculation device 102, and the three-dimensional image generation device 103 are configured to transmit and receive signals to and from each other. The control device 101, the dose calculation device 102, and the three-dimensional image generation device 103 are connected to each other via a computer network such as a LAN (Local Area Network).

[0032] (Skin dose indication) 3 , in this embodiment, the monitor 4 displays the X-ray dose calculated by the dose calculation device 102. Specifically, the monitor 4 is configured to display an angular dose image 42 generated by the dose calculation device 102. Specifically, the angular dose image 42 generated by the dose calculation device 102 is transmitted to the control device 101. Then, the control device 101 causes the monitor 4 to display the angular dose image 42.

[0033] 4, the dose calculation processing unit 70 of the dose calculation device 102 includes, as functional components, a positional relationship acquisition unit 71, a model dose calculation unit 72, an angle association unit 73, an angular dose calculation unit 74, an image generation unit 75, an irradiation region calculation unit 76, a storage processing unit 77, and a dose prediction unit 78. That is, the dose calculation processing unit 70 functions as the positional relationship acquisition unit 71, the model dose calculation unit 72, the angle association unit 73, the angular dose calculation unit 74, the image generation unit 75, the irradiation region calculation unit 76, the storage processing unit 77, and the dose prediction unit 78 by executing a predetermined program stored in the storage device.

[0034] As shown in Figure 5, in this embodiment, the positional relationship acquisition unit 71 (dose calculation processing unit 70) is configured to acquire the virtual positional relationship between the virtual model Pa and the imaging unit 2 based on the positional relationship between the tabletop 1 and the imaging unit 2.

[0035] Specifically, the dose calculation device 102 is configured to acquire the position and angle of the tabletop 1 and the position and angle of the imaging unit 2 from the control device 101. Then, the positional relationship acquisition unit 71 acquires the positional relationship between the tabletop 1 and the imaging unit 2 in the three-dimensional virtual space based on the acquired position and angle of the tabletop 1 and the position and angle of the imaging unit 2 (X-ray irradiation unit 21 and X-ray detection unit 22). The positional relationship acquisition unit 71 also acquires a virtual model Pa (see FIG. 6) representing the subject P lying on the tabletop 1 in the three-dimensional virtual space. The virtual model Pa is a three-dimensional model having a cylindrical shape. The virtual model Pa is pre-stored in a storage device of the dose calculation device 102. The size of the virtual model Pa may be changed depending on the body size (BMI: Body Mass Index, etc.) of the subject P. The positional relationship acquisition unit 71 then acquires the virtual positional relationship between the imaging unit 2 and the virtual model Pa in the three-dimensional virtual space. The position of the virtual model Pa in the three-dimensional virtual space is set based on the position and angle of the tabletop 1.

[0036] As shown in FIG. 6, in this embodiment, the model dose calculation unit 72 (dose calculation processing unit 70) is configured to calculate the dose distribution on the surface of the three-dimensional virtual model Pa based on the dose of X-rays irradiated to the subject P by X-ray irradiation by the imaging unit 2 (X-ray irradiation unit 21).

[0037] Specifically, the dose calculation device 102 acquires from the control device 101 imaging conditions such as the period of X-ray irradiation, the imaging unit angle, the tube voltage, the tube current, and the time interval between X-ray irradiation. The dose calculation device 102 also acquires from the control device 101 the dose of X-rays irradiated to the subject P and the imaging unit angle in association with each other. The model dose calculation unit 72 then calculates an integrated value of the dose on the surface of the virtual model Pa based on the dose of X-rays irradiated to the subject P, the imaging unit angle, and the virtual positional relationship between the imaging unit 2 and the virtual model Pa in the three-dimensional virtual space. The model dose calculation unit 72 then updates the integrated value of the dose on the surface of the virtual model Pa every time the imaging unit 2 irradiates X-rays. Specifically, the model dose calculation unit 72 calculates an integrated value of the dose for each infinitesimal element on the surface of the virtual model Pa, which is divided into infinitesimal elements.

[0038] As shown in FIG. 7, in this embodiment, the angle association unit 73 (dose calculation processing unit 70) is configured to associate the imaging unit angle with the surface of the virtual model Pa based on the imaging unit angle and the position on the surface of the virtual model Pa where X-rays are irradiated.

[0039] Specifically, the angle association unit 73 acquires positions on the surface of the virtual model Pa where X-rays are irradiated for each imaging unit angle at predetermined angular intervals, based on the virtual positional relationship between the imaging unit 2 and the virtual model Pa in the three-dimensional virtual space. For example, if the predetermined angular intervals are 10 degrees, the angle association unit 73 acquires the imaging unit angle when the imaging unit angle is vertical (reference direction) as (0,0), the imaging unit angle when tilted 10 degrees toward the LAO as (10,0), and the imaging unit angle when tilted 20 degrees toward the LAO as (20,0). Furthermore, the angle association unit 73 acquires the imaging unit angle when tilted 10 degrees toward the LAO and 10 degrees toward the CRA as (10,10). Based on the positional relationship between the imaging unit 2 and the virtual model Pa at predetermined angular intervals (for example, 10 degrees) in the three-dimensional virtual space, the angle association unit 73 maps the positions of the centers of the irradiation axes (centers of the field of view) of X-rays irradiated from the imaging unit 2 onto the surface of the virtual model Pa at predetermined angular intervals so as to associate them on the surface of the virtual model Pa. Then, the angle association unit 73 acquires angular regions partitioned on the surface of the virtual model Pa by connecting the positions of the centers of the irradiation axes (centers of the field of view) at predetermined angular intervals mapped on the surface of the virtual model Pa.

[0040] As shown in FIG. 8 , in this embodiment, the angular dose calculation unit 74 (dose calculation processing unit 70) is configured to calculate the dose in each of a plurality of angular regions defined at predetermined angular intervals of the image capture unit angle, based on the dose distribution on the surface of the virtual model Pa calculated by the model dose calculation unit 72 and the image capture unit angle associated with the surface of the virtual model Pa by the angle association unit 73. The image generation unit 75 (dose calculation processing unit 70) then generates an angular dose image 42 in which the magnitude of the dose in each of the plurality of angular regions calculated by the angular dose calculation unit 74 can be distinguished. In this embodiment, the angular dose image 42 is an image in which the plurality of angular regions are defined in a grid pattern at predetermined angular intervals of the image capture unit angle, and the magnitude of the dose in each of the plurality of grid-like angular regions can be distinguished. The angular dose image 42 generated by the image generation unit 75 is output from the dose calculation device 102 to the control device 101 and displayed on the monitor 4.

[0041] Specifically, the angular dose calculation unit 74 acquires the maximum dose value in each of the angular regions (see FIG. 7 ) partitioned at predetermined angular intervals on the surface of the virtual model Pa by the angle association unit 73 based on the dose distribution on the surface of the virtual model Pa. The image generation unit 75 then generates an angular dose image 42 in which each angular region is partitioned into a square at predetermined angular intervals (e.g., 10 degrees), with the directions of LAO and RAO as the horizontal axis and the directions of CRA and CAU as the vertical axis. That is, the angular dose image 42 is configured so that the size of the angular interval on the horizontal axis and the size of the angular interval on the vertical axis are approximately the same size (scale). The ranges of the vertical and horizontal axes are set based on the movable angle range of the imaging unit 2.

[0042] In this embodiment, the angular dose image 42 indicates the magnitude of the dose in each of the multiple angular regions by color coding. For example, in the angular dose image 42, the magnitude of the dose is indicated by five colors, purple, red, orange, yellow, and green, in descending order of dose. Note that in Figure 8, differences in the color coding are indicated by differences in hatching.

[0043] <Color scale image> 3 and 8, the monitor 4 is configured to display a color scale image 43, which indicates the color coding of multiple angular regions in the angle dose image 42 corresponding to the magnitude of the dose, separately from the angle dose image 42. In this embodiment, the monitor 4 is also configured to display preset dose thresholds 43a and 43b in the color scale image 43 in a distinguishable manner.

[0044] Specifically, the image generator 75 generates a color scale image 43 that indicates the color-coding criteria for the angular dose image 42. In the color scale image 43, regions are color-coded in purple, red, orange, yellow, and green, in descending order of dose, corresponding to the color coding of the angular dose image 42. Numerical values ​​indicating specific dose values ​​that serve as the color-coding criteria are displayed at the boundaries of the five regions. For example, in the color scale image 43, regions with a maximum dose greater than 4000 mGy are displayed as purple, regions with a maximum dose greater than 3000 mGy but less than or equal to 4000 mGy as red, regions with a maximum dose greater than 2000 mGy but less than or equal to 3000 mGy as orange, regions with a maximum dose greater than 1000 mGy but less than or equal to 2000 mGy as yellow, and regions with a maximum dose greater than 0 mGy but less than or equal to 1000 mGy as green.

[0045] Furthermore, a display indicating preset dose thresholds 43a and 43b is displayed so as to be superimposed on the color scale image 43. The thresholds 43a and 43b are set in advance by an operator such as a doctor. Furthermore, if the dose exceeds the thresholds 43a and 43b in the angle region currently being irradiated during X-ray irradiation, a warning message is displayed on the monitor 4. The warning message is displayed, for example, as text (text information) in a predetermined portion of the monitor 4. The display of the warning message on the monitor 4 is stopped after a predetermined time has elapsed or by an input operation on the operation unit 6, for example.

[0046] The monitor 4 may also be configured to display the total skin dose of the subject P during surgery. For example, the dose calculation processing unit 70 calculates the total dose on the entire body surface of the subject P based on the acquired X-ray dose. The calculated total dose is then output from the dose calculation device 102 to the control device 101, and is displayed on the monitor 4 by control processing by the control device 101.

[0047] <Change of position> 9 to 11, in this embodiment, when the positional relationship between the tabletop 1 and the image capture unit 2 is changed, the angle associating unit 73 is configured to update the association of the image capture unit angles on the surface of the virtual model Pa based on the virtual positional relationship acquired by the positional relationship acquiring unit 71. The angular dose calculating unit 74 is configured to update the dose in each of the plurality of angular regions based on the updated association of the image capture unit angles on the surface of the virtual model Pa. The image generating unit 75 is configured to regenerate the angular dose image 42 based on the updated dose in each of the plurality of angular regions.

[0048] Specifically, when an operation to change the position and angle of the tabletop 1 is received, the positional relationship acquisition unit 71 updates the position and angle of the virtual model Pa in the three-dimensional virtual space based on information indicating the position and angle of the tabletop 1 newly acquired from the control device 101. Furthermore, when an operation to change the position and angle of the imaging unit 2 is received, the positional relationship acquisition unit 71 updates the position and angle of the imaging unit 2 in the three-dimensional virtual space based on information indicating the position and angle of the imaging unit 2 newly acquired from the control device 101. In other words, when a signal indicating that the positional relationship between the tabletop 1 and the imaging unit 2 has been changed is received from the control device 101, the positional relationship acquisition unit 71 changes the virtual positional relationship between the virtual model Pa and the imaging unit 2 in the three-dimensional virtual space.

[0049] When the virtual positional relationship between the virtual model Pa and the imaging unit 2 in the three-dimensional virtual space is changed, the angle associating unit 73 reacquires (calculates) a new position on the surface of the virtual model Pa where X-rays are irradiated for each imaging unit angle at predetermined angle intervals, based on the changed virtual positional relationship, thereby updating the association (mapping) of the imaging unit angles on the surface of the virtual model Pa. Then, the angle associating unit 73 reacquires a newly partitioned angular region on the surface of the virtual model Pa based on the updated association (mapping).

[0050] The angular dose calculation unit 74 recalculates the dose in each of the plurality of angular regions divided at predetermined angular intervals based on the dose distribution on the surface of the virtual model Pa calculated by the model dose calculation unit 72 and the angular regions based on the association of the image capture unit angles updated by the angle association unit 73. The image generation unit 75 then updates the angular dose image 42 so that the magnitude of the dose in each of the plurality of newly recalculated angular regions can be distinguished. That is, when the positional relationship between the tabletop 1 and the image capture unit 2 is changed, the degree of dose distribution in the angular dose image 42 changes based on the dose in each of the newly recalculated angular regions. Note that when only the image capture unit angle of the image capture unit 2 is moved (changed) without moving the tabletop 1, the association of the image capture unit angle on the surface of the virtual model Pa in the 3D virtual space is not changed. That is, when only the image capture unit angle is changed, the angular dose image 42 is not updated, and the degree of dose distribution in the angular dose image 42 does not change.

[0051] For example, as shown in FIG. 9, when the tabletop 1 is moved in the longitudinal direction of the tabletop 1 (the vertical direction of the subject P) based on an input operation on the touch panel 5 or the operation unit 6, the degree of dose distribution in the angular dose image 42 shifts in the vertical direction (the CRA and CAU directions).

[0052] Also, as shown in FIG. 10, when the tabletop 1 is moved in the short direction of the tabletop 1 (left and right direction of the subject P) based on an input operation on the touch panel 5 or the operation unit 6, the degree of dose distribution in the angular dose image 42 shifts left and right (in the RAO and LAO directions).

[0053] Furthermore, as shown in FIG. 11, when the tabletop 1 is moved vertically based on an input operation on the touch panel 5 or the operation unit 6, the degree of dose distribution in the angular dose image 42 changes so as to be enlarged or reduced.

[0054] Similarly, when the angle of the tabletop 1 is changed by rotating it, the degree of dose distribution in the angular dose image 42 also changes. Furthermore, when the position of the imaging unit 2 relative to the tabletop 1 is moved, the degree of dose distribution in the angular dose image 42 also changes. Note that the change in the degree of dose distribution in the angular dose image 42 when the positional relationship between the tabletop 1 and the imaging unit 2 is changed is different from simple translation (shift) movement and scaling, because the correspondence of the imaging unit angle on the surface of the cylindrical virtual model Pa is changed.

[0055] <Changing angle intervals> 12 , in this embodiment, when an operation to change the size of the predetermined angular intervals dividing the plurality of angular regions is received via the touch panel 5 or the operation unit 6, the angular dose calculator 74 (dose calculation processor 70) is configured to calculate the dose in each of the plurality of angular regions divided by the changed predetermined angular intervals. The image generator 75 then generates an angular dose image 42 in which the magnitude of the dose in each of the plurality of angular regions with the changed predetermined angular intervals can be distinguished. In this embodiment, the monitor 4 is configured to display the angular dose image 42 with the changed size of the predetermined angular intervals.

[0056] Specifically, when an input operation to change the size of the predetermined angular interval is received based on an input operation on the touch panel 5 or the operation unit 6, the angle mapping unit 73 updates the mapping of the image capture unit angles on the surface of the virtual model Pa so that the virtual model Pa is divided into predetermined angular intervals of the changed size, thereby reacquiring newly divided angular regions on the surface of the virtual model Pa. The angular dose calculation unit 74 then recalculates the dose in each of the angular regions of the updated size. The image generation unit 75 then updates the angular dose image 42 so that the dose in each of the newly calculated angular regions can be distinguished. The image generation unit 75 also generates the angular dose image 42 in which the size of each divided angular region has been changed in accordance with the change in the angular interval. For example, if the predetermined angular interval is changed from 10 degrees to 5 degrees, the size of the sections in the angular dose image 42 is halved without changing the size of the angular dose image 42 itself. In addition, in the angular dose image 42 divided into 5-degree sections, the dose is displayed in different colors so that it can be distinguished based on the distribution of dose in angular regions divided into 5-degree sections on the surface of the virtual model Pa.

[0057] <Display of irradiation area> As shown in FIG. 8, in this embodiment, the monitor 4 is configured to display a display (irradiation area display 42a) indicating an angular area included in the irradiation area from among a plurality of angular areas in the angular dose image 42.

[0058] Specifically, in this embodiment, the irradiation area calculation unit 76 (dose calculation processing unit 70) is configured to calculate an irradiation area, which is an area on the surface of the virtual model Pa irradiated with X-rays at the current imaging unit angle. Specifically, the irradiation area calculation unit 76 calculates an irradiation area on the surface of the virtual model Pa irradiated with X-rays at the current imaging unit angle, based on the virtual positional relationship between the virtual model Pa and the imaging unit 2 in the three-dimensional virtual space acquired by the positional relationship acquisition unit 71 and the imaging conditions acquired from the control device 101. The irradiation area calculation unit 76 then acquires, as an angular area included in the irradiation area, an angular area that includes a part or the entire irradiation area irradiated with X-rays from among the multiple angular areas partitioned at predetermined angular intervals by the angle association unit 73. The image generation unit 75 superimposes an irradiation area display 42a, which indicates an angular area included in the irradiation area acquired by the irradiation area calculation unit 76, on the angular dose image 42. Then, angular dose image 42 on which irradiation region display 42 a is superimposed is output to control device 101 and displayed on monitor 4.

[0059] The irradiation area display 42a indicates the irradiation area so as to surround the entire angular area included in the irradiation area. The irradiation area display 42a may color the angular area included in the irradiation area or may display it by superimposing diagonal lines or the like. The irradiation area display 42a includes a display that allows identification of the angular area including the center of the irradiation axis of the irradiated X-rays (center of field of view) from the angular area included in the irradiation area. For example, the irradiation area display 42a includes a cross (plus sign) mark indicating the angular area including the center of the irradiation axis (center of field of view) in the irradiation area. The size and shape of the irradiation area display 42a change depending on the irradiation area (field of view size) of the X-rays irradiated from the X-ray irradiator 21, the opening amount of the collimator 21b, or the distance between the X-ray irradiator 21 and the X-ray detector 22 (SID: focus-detector distance). The irradiation area display 42a may be a square area in the angular dose image 42, or may be a rectangle or a polygon.

[0060] As shown in FIG. 3 , in this embodiment, the monitor 4 is configured to identifiably display the maximum value of the dose in an angular region included in the irradiation region (irradiation region display 42a), separately from the angular dose image 42. Specifically, the irradiation region calculation unit 76 is configured to acquire the angular region with the maximum dose from among multiple angular regions included in the irradiation region. A signal indicating the dose in the angular region with the maximum dose is then output from the dose calculation device 102 to the control device 101. The control device 101 displays, on the monitor 4, a maximum value display 44 indicating the maximum value of the dose in the angular region included in the irradiation region (irradiation region display 42a). The maximum value display 44 displays the maximum value of each of the doses in the multiple angular regions included in the irradiation region (irradiation region display 42a) in the same color as the color coding of the angular dose image 42. Furthermore, the maximum value display 44 may display a warning message when the dose exceeds a preset dose (e.g., a threshold value 43a).

[0061] <Changing the imaging unit angle> The X-ray imaging system 100 is configured to change the image capture unit angle based on an input operation via the touch panel 5 or the operation unit 6. For example, in this embodiment, the operation unit 6 is configured to accept an operation to select one of multiple angular regions in the angular dose image 42 displayed on the monitor 4. For example, an operator such as a doctor performs a selection operation by clicking one of the multiple angular regions partitioned into a grid pattern in the angular dose image 42 displayed on the monitor 4 using a pointer also displayed on the monitor 4. When this selection operation is accepted by the operation unit 6, the control device 101 changes the image capture unit angle so that X-rays are irradiated onto the selected one of the multiple angular regions. That is, in this embodiment, when the operation unit 6 accepts an operation to select one of the multiple angular regions in the angular dose image 42 (selection operation), the movement mechanism 3 is configured to change the image capture unit angle so that X-rays are irradiated onto the selected angular region.

[0062] The irradiation region calculation unit 76 acquires a new irradiation region display 42a each time the imaging unit angle of the imaging unit 2 is changed. The irradiation region calculation unit 76 is also configured to acquire a new irradiation region display 42a when the positional relationship between the imaging unit 2 and the tabletop 1 is changed in a manner other than the imaging unit angle. In the X-ray imaging system 100, when only the imaging unit angle of the imaging unit 2 is changed, only the irradiation region display 42a is moved (changed) without changing the dose distribution in the angular dose image 42. When selecting an imaging unit angle in the angular dose image 42, a color-coded display (colored portion) indicating the magnitude of the dose in the angular dose image 42 may be displayed semitransparently to improve the visibility of the irradiation region display 42a. While the imaging unit angle is being changed (while the imaging unit 2 is being moved), the irradiation region display 42a during movement and the irradiation region display 42a at the destination may be displayed on the angular dose image 42.

[0063] 13, the monitor 4 is configured to identifiably display, among multiple angular regions in the angular dose image 42, angular regions for which X-ray irradiation is recommended. For example, the image generation unit 75 (dose calculation processing unit 70) colors the recommended angular regions in the angular dose image 42 to indicate the imaging unit angles for which X-ray irradiation is recommended. Note that the display (coloring) indicating the recommended imaging unit angles (angular regions) is displayed on the monitor 4 when the maximum dose in the angular region included in the irradiation region (irradiation region display 42a) at the current imaging unit angle becomes greater than a predetermined dose (for example, threshold value 43a).

[0064] The recommended imaging unit angle (angle region) is selected based on the region of the subject P to be treated or examined, from information previously input by the operator, a database stored in the system, or a database acquired via a network. For example, when imaging cardiac blood vessels, a recommended imaging unit angle is set in advance for each type of blood vessel. If imaging of the right coronary artery (RCA) is set in advance based on an input operation on the touch panel 5 or the operation unit 6, the image generation unit 75 displays the recommended imaging unit angle (angle region) set to correspond to the right coronary artery in color in the angular dose image 42. If the recommended imaging unit angle (angle region) has a rank (priority), a display (text information) that identifies the rank, such as "1st," "2nd," and "3rd," is also displayed. The image generation unit 75 displays the imaging unit angle (angle region) corresponding to each rank in color in the angular dose image 42 so that the rank can be identified. In this case, the recommended imaging unit angle (angle area) may be displayed while excluding areas where the dose is already high.

[0065] <Timeline display> 14, the monitor 4 displays a timeline display 45 for checking the progress of the irradiated dose. The timeline display 45 is displayed on the monitor 4 based on an input operation on the touch panel 5 or the operation unit 6, for example. The X-ray imaging system 100 is configured to display an angular dose image 42 at a predetermined time in the past on the monitor 4 based on a selection operation on the timeline display 45.

[0066] Specifically, in this embodiment, the storage processing unit 77 (dose calculation processing unit 70) is configured to store history information of the dose distribution on the surface of the virtual model Pa based on the irradiation of X-rays by the imaging unit 2. Every time the imaging unit 2 irradiates X-rays, the storage processing unit 77 stores the history of the irradiated X-ray dose in the storage device of the dose calculation device 102.

[0067] Then, the dose calculation processing unit 70 acquires from the storage device history information including the dose value at the selected predetermined past timing based on an operation to select any timing from the time series in the timeline display 45. Here, in the X-ray imaging system 100, in order to capture an X-ray image 41 as a moving image, X-rays are continuously irradiated over a predetermined period in capturing one X-ray image 41. In the timeline display 45, predetermined past timings are displayed in a selectable manner for each predetermined period for generating one X-ray image 41 of a moving image.

[0068] The monitor 4 is configured to display an angular dose image 42 at a predetermined time in the past based on the history information stored by the storage processor 77. That is, based on the stored history information, the dose distribution on the surface of the virtual model Pa at a selected predetermined time in the past and the virtual positional relationship between the imaging unit 2 and the virtual model Pa are acquired. Then, the image generator 75 generates an angular dose image 42 based on the dose values ​​at the predetermined time in the past by executing a process similar to that used to generate the current angular dose image 42. The generated angular dose image 42 at the predetermined time in the past is output to the control device 101 and displayed on the monitor 4. The storage processor 77 may be configured to directly store the generated angular dose image 42 in a storage device for each time an X-ray image 41 is generated.

[0069] Furthermore, the X-ray imaging system 100 is configured to display a predicted angular dose image 42 on the monitor 4 based on a selection operation on the timeline display 45.

[0070] Specifically, in this embodiment, the dose prediction unit 78 (dose calculation processing unit 70) is configured to calculate a predicted value of the dose of X-rays irradiated by the imaging unit 2, based on the dose distribution on the surface of the virtual model Pa calculated by the model dose calculation unit 72. For example, the dose calculation processing unit 70 accepts selection of a predicted portion of the timeline display 45 (a portion beyond the current timing (current position)) based on an input operation on the touch panel 5 or the operation unit 6. Based on the acceptance of the selection of the predicted portion on the timeline display 45, the dose prediction unit 78 predicts an increase in the dose if X-ray irradiation in the current irradiation area is continued. The dose prediction unit 78 predicts an increase in the dose if irradiation is continued, for example, based on history information. The dose prediction unit 78 may also predict an increase in the dose in the current irradiation area based on a preset database. The dose prediction unit 78 may also calculate a predicted value of the dose if the imaging conditions are changed.

[0071] The dose prediction unit 78 then calculates a predicted value of the dose, thereby calculating a predicted value of the dose distribution on the surface of the virtual model Pa. The monitor 4 is configured to display a predicted angular dose image 42 based on the predicted value predicted by the dose prediction unit 78. That is, the image generation unit 75 generates the predicted angular dose image 42 based on the predicted value of the dose distribution on the surface of the virtual model Pa. The generated predicted angular dose image 42 is then output to the control device 101 and displayed on the monitor 4.

[0072] (Touch panel details) As shown in FIG. 15 , in this embodiment, the touch panel 5 displays a selectable imaging unit angle. The touch panel 5 also accepts an input operation to change the imaging unit angle. The touch panel 5 displays a list of multiple imaging unit angle displays 5a so that the imaging unit angle can be selected, based on a database stored in a storage unit such as a flash memory included in the touch panel 5, a storage device of the control device 101, or a storage device of the dose calculation device 102. The touch panel 5 also displays a current angle display 5b indicating the current imaging unit angle so that it can be distinguished from the multiple imaging unit angle displays 5a displayed as a list. Specifically, the touch panel 5 acquires information indicating the position of the imaging unit 2 from the control device 101. Based on the information acquired from the control device 101, the touch panel 5 displays the background of the multiple imaging unit angle displays 5a displayed as a list in white and the background of the current angle display 5b in blue, thereby visually distinguishing the current imaging unit angle.

[0073] Furthermore, the touch panel 5 displays a non-recommended angle indicator 5c, which indicates an imaging unit angle that is not recommended, in a manner that allows the imaging unit angle to be visually distinguished from among the multiple imaging unit angle indicators 5a displayed as a list. Specifically, the touch panel 5 acquires doses calculated for multiple angle regions from the dose calculation device 102. The touch panel 5 then displays the non-recommended angle indicator 5c, which indicates an imaging unit angle that is included in an angle region exceeding a predetermined dose (for example, threshold value 43a) from among the imaging unit angles corresponding to the multiple imaging unit angle indicators 5a, in a manner that allows the imaging unit angle to be visually distinguished as a non-recommended imaging unit angle. For example, the touch panel 5 displays the non-recommended angle indicator 5c with a red background, thereby allowing the imaging unit angle to be visually distinguished.

[0074] The touch panel 5 also displays a recommended angle indicator 5d, which is an indicator (for example, a star mark) indicating the imaging unit angle at which X-ray irradiation is recommended. The recommended imaging unit angle is selected based on the region of the subject P to be treated or examined, from information previously input by the operator, a database stored in the system, or a database obtained via a network. The touch panel 5 also selectably displays a desired angle indicator 5e, which indicates a desired imaging unit angle previously registered by the operator. The recommended imaging unit angle and the desired imaging unit angle may be stored in a storage unit such as a flash memory included in the touch panel 5, or may be stored in a storage unit of the control device 101 or a storage unit of the dose calculation device 102.

[0075] 16 , in this embodiment, the touch panel 5 is configured to display an angular dose image 42. Specifically, the touch panel 5 acquires the angular dose image 42 generated by the image generator 75 from the dose calculation device 102. The touch panel 5 is configured to display the acquired angular dose image 42 by switching the display based on, for example, an input operation by the operator.

[0076] (3D image display) 3 and 17, the monitor 4 displays a three-dimensional image 46 of the inside of the body of the subject P, which has been acquired in advance. Specifically, the three-dimensional image 46 is generated by a three-dimensional image generating device 103. The three-dimensional image generating device 103 generates the three-dimensional image 46 representing the inside of the body of the subject P based on three-dimensional image data of the inside of the body of the subject P, which has been acquired in advance by a CT (Computed Tomography) device or the like. The three-dimensional image 46 generated by the three-dimensional image generating device 103 is then output from the three-dimensional image generating device 103 to the control device 101, and is displayed on the monitor 4.

[0077] 17 , in this embodiment, the monitor 4 is configured to identifiably display the dose in an angular region at the imaging unit angle corresponding to the display angle of the displayed 3D image 46. Specifically, the 3D image generation device 103 generates an angle indicator 46a along with the 3D image 46. The angle indicator 46a indicates the display angle of the displayed 3D image 46 by indicating the positional relationship between an indication of the subject P, which is the subject, and an indication of the imaging unit 2, which is the viewpoint, so as to correspond to the spatial viewpoint (camera position) of the displayed 3D image 46. The 3D image generation device 103 acquires doses in each of a plurality of angular regions from the dose calculation device 102, and causes the angle indicator 46a to identifiably display the magnitude of the acquired dose. For example, the 3D image generation device 103 displays the indication of the imaging unit 2 in the angle indicator 46a in the same color as the angular dose image 42. That is, the 3D image generating device 103 distinguishably displays the dose in the angle region including the imaging unit angle corresponding to the current display angle by color-coding the angle indicator 46a. Note that the dose in the angle region including the imaging unit angle corresponding to the current display angle may be displayed as an icon in the same color as the angle dose image 42, separately from the angle indicator 46a.

[0078] (Control process according to this embodiment) Next, a control processing flow relating to the dose display method by the X-ray imaging system 100 according to this embodiment will be described with reference to Fig. 18. Steps 201 to 205 represent control processing by the dose calculation processing unit 70 (dose calculation device 102). Step 206 represents control processing by the control device 101.

[0079] First, in step 201, a virtual positional relationship between the virtual model Pa and the imaging unit 2 is acquired based on the positional relationship between the tabletop 1 and the imaging unit 2.

[0080] Next, in step 202, based on the dose of X-rays irradiated onto the subject P by the X-ray irradiation from the imaging unit 2, the dose distribution on the surface of the three-dimensional virtual model Pa is calculated.

[0081] Next, in step 203, the image pickup unit angle is associated with the surface of the virtual model Pa based on the image pickup unit angle and the position on the surface of the virtual model Pa where the X-rays are irradiated.

[0082] Next, in step 204, based on the dose distribution on the surface of the virtual model Pa calculated in step 202 and the imaging unit angle associated with the surface of the virtual model Pa in step 203, the dose in each of a plurality of angular regions partitioned at predetermined angular intervals of the imaging unit angle is calculated.

[0083] Next, in step 205, an angular dose image 42 is generated that allows the magnitude of the dose to be distinguished in each of the calculated angular regions.

[0084] Next, in step 206, the angular dose image 42 is displayed on the monitor 4. Specifically, the generated angular dose image 42 is output from the dose calculation device 102 to the control device 101, and is thereby displayed on the monitor 4. Note that either the calculation of the dose distribution on the surface of the virtual model Pa in step 202 or the association of the imaging unit angle on the surface of the virtual model Pa in step 203 may be performed first.

[0085] (Effects of this embodiment) In this embodiment, the following effects can be obtained.

[0086] As described above, the X-ray imaging system 100 of this embodiment calculates the dose in each of a plurality of angular regions defined at predetermined angular intervals of the imaging unit angle based on the calculated dose distribution on the surface of the virtual model Pa and the imaging unit angle associated with the surface of the virtual model Pa. The X-ray imaging system 100 of this embodiment then displays an angular dose image 42 that allows the magnitude of the dose in each of the plurality of angular regions to be distinguished. This allows an operator (surgeon) such as a doctor to visually check the displayed angular dose image 42 and thus easily determine an imaging unit angle that provides a relatively low dose. As a result, an appropriate imaging unit angle that provides a relatively low dose can be easily selected to prevent a localized increase in the dose on the body surface of the subject P.

[0087] Furthermore, in this embodiment, further effects can be obtained by configuring as follows.

[0088] That is, in this embodiment, the dose calculation processing unit 70 includes a positional relationship acquisition unit 71 that acquires a virtual positional relationship between the virtual model Pa and the imaging unit 2 based on the positional relationship between the tabletop 1 and the imaging unit 2. The angle association unit 73 (dose calculation processing unit 70) is configured to update the association of imaging unit angles on the surface of the virtual model Pa based on the virtual positional relationship acquired by the positional relationship acquisition unit 71 when the positional relationship between the tabletop 1 and the imaging unit 2 is changed. The angular dose calculation unit 74 (dose calculation processing unit 70) is configured to update the dose in each of the multiple angle regions based on the updated association of imaging unit angles on the surface of the virtual model Pa. With this configuration, for example, even when the positional relationship between the tabletop 1 and the imaging unit 2 is changed by moving the tabletop 1, the association of imaging unit angles on the surface of the virtual model Pa is updated, thereby updating the angular dose image 42 so that the dose distribution is accurately displayed. As a result, even if the positional relationship between the tabletop 1 and the imaging unit 2 is changed, a doctor or other worker can easily and accurately select an appropriate imaging unit angle by visually checking the angular dose image 42.

[0089] Furthermore, in this embodiment, the X-ray imaging system 100 includes a touch panel 5 and an operation unit 6 that accept input operations by an operator. When an operation to change the size of the predetermined angular intervals that divide the plurality of angular regions is accepted by the touch panel 5 or the operation unit 6, the angular dose calculation unit 74 (dose calculation processing unit 70) is configured to calculate the dose in each of the plurality of angular regions divided by the changed predetermined angular intervals. The monitor 4 (display unit) is configured to display an angular dose image 42 that allows the magnitude of the dose in each of the plurality of angular regions whose size of the predetermined angular interval has been changed to be distinguished. With this configuration, an operator such as a doctor can change the size of the angular intervals of the plurality of angular regions in the angular dose image 42 by operating the touch panel 5 or the operation unit 6, thereby easily switching between checking the dose distribution in detail and checking the dose distribution overall.

[0090] Furthermore, in this embodiment, the monitor 4 (display unit) is configured to display an angular dose image 42 in which a plurality of angular regions are partitioned in a grid pattern at predetermined angular intervals of the imaging unit angle, and in which the magnitude of the dose in each of the plurality of angular regions partitioned in the grid pattern can be distinguished. With this configuration, since the plurality of angular regions are partitioned in a grid pattern at predetermined angular intervals in the angular dose image 42, an operator such as a doctor can easily recognize the distribution of the dose in two orthogonal angular directions, the left-right direction (LAO and RAO) and the up-down direction (CRA and CAU), of the subject P. Therefore, an operator such as a doctor can easily determine to which imaging unit angle to change in the two orthogonal angular directions, the left-right direction (LAO and RAO) and the up-down direction (CRA and CAU), of the subject P, in order to prevent a localized increase in the dose on the body surface of the subject P.

[0091] Furthermore, in this embodiment, the dose calculation processing unit 70 includes a memory processing unit 77 that stores historical information about the dose distribution on the surface of the virtual model Pa based on the X-ray irradiation by the imaging unit 2. The monitor 4 (display unit) is configured to display an angular dose image 42 at a predetermined time in the past based on the historical information stored by the memory processing unit 77. With this configuration, an operator such as a doctor can check the angular dose image 42 at a predetermined time in the past, and can easily check the progress of the dose increase over time. Therefore, when selecting a new imaging unit angle for X-ray irradiation, an appropriate imaging unit angle can be more easily selected by referring to the progress of the dose increase over time.

[0092] Furthermore, in this embodiment, the dose calculation processing unit 70 includes a dose prediction unit 78 that calculates a predicted value of the dose of X-rays irradiated by the imaging unit 2 based on the dose distribution on the surface of the virtual model Pa calculated by the model dose calculation unit 72 (dose calculation processing unit 70). The monitor 4 (display unit) is configured to display a predicted angle dose image 42 based on the predicted value predicted by the dose prediction unit 78. With this configuration, an operator such as a doctor can confirm a prediction of how the dose of the subject P will increase if X-ray irradiation is continued, and can accurately determine whether to continue X-ray irradiation with the current imaging unit angle or to change the imaging unit angle and irradiate X-rays. As a result, it is possible to effectively prevent the dose from locally increasing on the body surface of the subject P.

[0093] In this embodiment, the dose calculation processing unit 70 also includes an irradiation area calculation unit 76 that calculates an irradiation area, which is an area on the surface of the virtual model Pa irradiated with X-rays at the current imaging unit angle. The monitor 4 (display unit) is configured to display an indication (irradiation area indication 42a) indicating an angular area included in the irradiation area from among the multiple angular areas in the angular dose image 42. With this configuration, by visually checking the angular dose image 42, it is possible to confirm in which angular area of ​​the multiple angular areas the dose will increase if X-rays are irradiated at the current imaging unit angle. Therefore, an operator such as a doctor can easily determine whether the dose of the subject P will be too high if X-rays are irradiated at the current imaging unit angle. As a result, an operator such as a doctor can easily determine whether to change the imaging unit angle to prevent a local increase in the dose on the body surface of the subject P.

[0094] Furthermore, in this embodiment, the monitor 4 (display unit) is configured to display a maximum value display 44, separate from the angular dose image 42, to identify the maximum value of the dose in the angular region included in the irradiation region. This configuration allows a doctor or other worker to easily check the maximum value of the dose at the current imaging unit angle. This allows the doctor or other worker to more easily determine whether or not to change the imaging unit angle.

[0095] Furthermore, in this embodiment, the monitor 4 (display unit) is configured to identifiably display, among multiple angular regions in the angular dose image 42, angular regions for which X-ray irradiation is recommended. This configuration allows an operator such as a doctor to more easily determine which imaging unit angle is appropriate when changing the imaging unit angle. Therefore, when changing the imaging unit angle, the effort required to select a new imaging unit angle can be reduced.

[0096] Furthermore, in this embodiment, when an operation to select one of the plurality of angular regions in the angular dose image 42 is received by the operation unit 6, the movement mechanism 3 is configured to change the image capture unit angle so that X-rays are irradiated onto the selected angular region. With this configuration, an operator such as a doctor can easily select a new image capture unit angle by performing an operation to select one of the plurality of angular regions in the angular dose image 42. Therefore, an operator such as a doctor can easily prevent a local increase in dose on the body surface of the subject P by selecting an angular region with a relatively small dose from among the plurality of angular regions in the angular dose image 42.

[0097] Furthermore, in this embodiment, the monitor 4 (display unit) is configured to display an angular dose image 42 in which the magnitude of the dose in each of a plurality of angular regions is represented by a different color, and to display a color scale image 43, separately from the angular dose image 42, which indicates the color coding of the plurality of angular regions in the angular dose image 42 corresponding to the magnitude of the dose. With this configuration, the magnitude of the dose is displayed by a different color in the angular dose image 42, and the color scale image 43 indicating the color coding corresponding to the magnitude of the dose is displayed, so that an operator such as a doctor can more easily visually recognize the distribution of magnitudes of the dose in the angular dose image 42. This makes it easy to recognize in which angular region the dose is high, and therefore makes it easier to select an appropriate imaging unit angle.

[0098] Furthermore, in this embodiment, the monitor 4 (display unit) is configured to distinguishably display preset dose thresholds 43a and 43b in the color scale image 43. With this configuration, an operator such as a doctor can easily visually recognize which angular regions have doses exceeding the preset thresholds 43a and 43b by checking the color coding in the angle dose image 42, since the preset dose thresholds 43a and 43b are displayed in the color scale image 43. Therefore, by checking the angle dose image 42, the specific magnitude of the dose on the body surface of the subject P can be easily recognized.

[0099] Furthermore, in this embodiment, the X-ray imaging system 100 includes a touch panel 5, separate from the monitor 4 (display unit), that displays a plurality of selectable imaging unit angles and accepts an input operation to change the imaging unit angle. The touch panel 5 is configured to display an angular dose image 42. With this configuration, an operator such as a doctor can check the angular dose image 42 displayed on the touch panel 5 when changing the imaging unit angle by operating the touch panel 5. This reduces the amount of movement of the viewpoint compared to when checking the angular dose image 42 displayed on a monitor 4 separate from the touch panel 5, thereby reducing the burden on the operator such as a doctor when selecting an imaging unit angle.

[0100] Furthermore, in this embodiment, the monitor 4 (display unit) is configured to display a three-dimensional image 46 of the inside of the body of the subject P that has been acquired in advance, and to identifiably display on the angle indicator 46a the dose in an angular region at the imaging unit angle that corresponds to the display angle of the displayed three-dimensional image 46. With this configuration, an operator such as a doctor can more easily select an imaging unit angle in an angular region with a relatively small dose when selecting an appropriate imaging unit angle while visually checking the three-dimensional image 46, because the dose in an angular region at the imaging unit angle that corresponds to the display angle of the displayed three-dimensional image 46 is identifiably displayed on the angle indicator 46a.

[0101] The dose display method of this embodiment, configured as described above, calculates the dose in each of multiple angular regions defined at predetermined angular intervals of the imaging unit angle based on the calculated dose distribution on the surface of the virtual model Pa and the imaging unit angle associated with the surface of the virtual model Pa. The X-ray imaging system 100 of this embodiment then displays an angular dose image 42 that allows the magnitude of the dose in each of the multiple angular regions to be distinguished. This allows an operator (surgeon) such as a doctor to visually check the displayed angular dose image 42 and thus easily determine an imaging unit angle that provides a relatively low dose. As a result, a dose display method can be provided that allows the operator to easily select an appropriate imaging unit angle that provides a relatively low dose in order to prevent a localized increase in the dose on the body surface of the subject P.

[0102] [Variations] The embodiments disclosed herein should be considered to be illustrative and not restrictive in all respects. The scope of the present invention is defined by the claims, not by the description of the above embodiments, and includes all modifications (variations) within the meaning and scope of the claims.

[0103] For example, in the above embodiment, the imaging unit 2 has been described as having a single-plane mechanism in which one X-ray irradiator 21 and one X-ray detector 22 are provided, but the present invention is not limited to this. In the present invention, the imaging unit 2 may be configured as a bi-plane mechanism in which two X-ray irradiators 21 and two X-ray detectors 22 are provided. In this case, two irradiation regions (irradiation region displays 42a) are displayed in the angular dose image 42 so as to correspond to the two X-ray irradiators 21.

[0104] Furthermore, in the above embodiment, an example was shown in which the correspondence between the imaging unit angles on the surface of the virtual model Pa was updated when the positional relationship between the tabletop 1 and the imaging unit 2 was changed, but the present invention is not limited to this. For example, even when the positional relationship between the tabletop 1 and the imaging unit 2 has not changed, the correspondence between the imaging unit angles on the surface of the virtual model Pa may be configured to be updated every time the imaging unit angle is changed.

[0105] Furthermore, in the above embodiment, an example was shown in which the size of the predetermined angular intervals dividing the plurality of angular regions was changed based on input operations on the touch panel 5 and the operation unit 6, but the present invention is not limited to this. For example, the angular dose image 42 may be configured to display the dose distribution calculated on the surface of the virtual model Pa as is, in association with the imaging unit angle. That is, the angular dose image 42 may display a smooth (more detailed) dose distribution based on the dose calculated for each infinitesimal element in the virtual model Pa, without dividing the angular regions into a grid pattern.

[0106] In the above embodiment, angular dose images 42 obtained at each timing at which X-ray images 41 are captured as moving images are displayed as angular dose images 42 obtained at a predetermined timing in the past, but the present invention is not limited to this. For example, angular dose images 42 obtained at predetermined time intervals may be displayed on monitor 4 as angular dose images 42 obtained at a predetermined timing in the past.

[0107] In the above embodiment, an example was shown in which an angular dose image 42 predicted when X-ray irradiation is continued in an irradiation area at the current imaging unit angle is displayed, but the present invention is not limited to this. For example, an angular dose image 42 predicted when the imaging unit angle is changed may be displayed.

[0108] In the above embodiment, an example has been shown in which the irradiation area (irradiation area display 42a) is also displayed in the angular dose image 42, but the present invention is not limited to this. For example, the irradiation area does not have to be displayed in the angular dose image 42. Furthermore, instead of displaying the irradiation area so as to surround the entire angular area including the irradiation area, the irradiation area may be displayed by displaying a more detailed range separately from the division of each angular area.

[0109] In the above embodiment, the maximum value of the dose in the angle range included in the irradiation area (maximum value display 44) is displayed, but the present invention is not limited to this. For example, the average value of the dose in the angle range included in the irradiation area may be displayed.

[0110] In the above embodiment, the recommended angular region is indicated by a predetermined color in the angular dose image 42, but the present invention is not limited to this. For example, the recommended angular region may be indicated by surrounding it with a color.

[0111] In the above embodiment, an example was shown in which one angular region including the imaging unit angle at which the next X-ray irradiation will be performed is selected from among the multiple angular regions in the angular dose image 42 displayed on the monitor 4 (display unit), but the present invention is not limited to this. For example, one angular region including the imaging unit angle at which the next X-ray irradiation will be performed may be selected from among the multiple angular regions in the angular dose image 42 displayed on the touch panel 5.

[0112] Furthermore, in the above embodiment, an example has been shown in which angular dose image 42 and color scale image 43 are displayed side by side on monitor 4 (display unit), but the present invention is not limited to this. For example, color scale image 43 may be temporarily displayed based on an input operation on touch panel 5 and operation unit 6. Similarly, threshold values ​​43a and 43b in color scale image 43 may be temporarily displayed based on an input operation.

[0113] In the above embodiment, the angular dose image 42 is displayed by switching the display on the touch panel 5 based on an input operation, but the present invention is not limited to this. For example, a plurality of image capture unit angle displays 5a and the angular dose image 42 may be displayed side by side.

[0114] In the above embodiment, an example has been shown in which the X-ray image 41, the angular dose image 42, and the three-dimensional image 46 are displayed on the monitor 4 (display unit), but the present invention is not limited to this. For example, the X-ray image 41 may be displayed on a display device provided separately from the monitor 4. Furthermore, the three-dimensional image 46 may be displayed on a display device provided separately from the monitor 4.

[0115] In the above embodiment, the control device 101 that controls X-ray imaging, the dose calculation device 102 that calculates the dose, and the 3D image generation device 103 that generates the 3D image 46 are provided as separate devices, but the present invention is not limited to this. For example, two or more of the control of X-ray imaging, the calculation of the dose, and the generation of the 3D image 46 may be performed by a common processing device.

[0116] In the above embodiment, for convenience of explanation, the control processing in the X-ray imaging system 100 is explained using a flow-driven flowchart in which processing is performed sequentially according to a processing flow, but the present invention is not limited to this. In the present invention, the control processing in the X-ray imaging system 100 may be performed by event-driven processing in which processing is performed on an event-by-event basis. In this case, the control processing may be performed completely event-driven, or may be performed in a combination of event-driven and flow-driven processing.

[0117] [Aspect] It will be appreciated by those skilled in the art that the exemplary embodiments described above are examples of the following aspects.

[0118] (Item 1) an imaging unit including an X-ray irradiation unit having an X-ray source that irradiates X-rays onto a subject lying on a tabletop, and an X-ray detection unit that detects the X-rays irradiated from the X-ray irradiation unit; a moving mechanism for changing an imaging unit angle, which is the angle of the imaging unit; a dose calculation processing unit that calculates the dose of X-rays irradiated to the subject; a display unit that displays the X-ray dose calculated by the dose calculation processing unit, The dose calculation processing unit a model dose calculation unit that calculates a dose distribution on a surface of a three-dimensional virtual model representing the subject lying on the tabletop based on the dose of X-rays irradiated onto the subject by the X-ray irradiation from the imaging unit; an angle association unit that associates the imaging unit angle with the surface of the virtual model based on the imaging unit angle and a position on the surface of the virtual model where X-rays are irradiated; an angle dose calculation unit that calculates a dose in each of a plurality of angle regions partitioned at predetermined angle intervals of the image capturing unit angle, based on the dose distribution on the surface of the virtual model calculated by the model dose calculation unit and the image capturing unit angle associated with the surface of the virtual model by the angle association unit, The display unit is configured to display an angular dose image in which the magnitude of the dose in each of the plurality of angular regions calculated by the angular dose calculation unit can be distinguished.

[0119] (Item 2) the dose calculation processing unit further includes a positional relationship acquisition unit that acquires a virtual positional relationship between the virtual model and the imaging unit based on a positional relationship between the tabletop and the imaging unit; the angle associating unit is configured to update the association of the angle of the imaging unit on the surface of the virtual model based on the virtual positional relationship acquired by the positional relationship acquiring unit when a positional relationship between the tabletop and the imaging unit is changed, Item 1. The X-ray imaging system according to item 1, wherein the angular dose calculation unit is configured to update the dose in each of the plurality of angular regions based on the correspondence of the imaging unit angle on the updated surface of the virtual model.

[0120] (Item 3) further comprising an operation unit that accepts input operations by an operator; the angular dose calculation unit is configured, when an operation to change the size of the predetermined angular intervals dividing the plurality of angular regions is accepted by the operation unit, to calculate a dose in each of the plurality of angular regions divided by the predetermined angular intervals whose size has been changed; 3. The X-ray imaging system according to claim 1, wherein the display unit is configured to display the angular dose image in which the magnitude of the dose in each of the plurality of angular regions in which the size of the predetermined angular interval is changed can be distinguished.

[0121] (Item 4) 4. The X-ray imaging system according to any one of items 1 to 3, wherein the display unit is configured to display the angular dose image in which the plurality of angular regions are divided into a grid at the predetermined angular intervals of the imaging unit angle, and in which the magnitude of the dose in each of the plurality of angular regions divided into the grid can be distinguished.

[0122] (Item 5) the dose calculation processing unit further includes a storage processing unit that stores history information of a dose distribution on a surface of the virtual model based on the X-ray irradiation by the imaging unit, The X-ray imaging system according to any one of items 1 to 4, wherein the display unit is configured to display the angular dose image at a predetermined timing in the past based on the history information stored by the memory processing unit.

[0123] (Item 6) the dose calculation processing unit further includes a dose prediction unit that calculates a predicted value of a dose of X-rays irradiated by the imaging unit based on the dose distribution on the surface of the virtual model calculated by the model dose calculation unit; 6. The X-ray imaging system according to any one of items 1 to 5, wherein the display unit is configured to display the predicted angular dose image based on the predicted value predicted by the dose prediction unit.

[0124] (Item 7) the dose calculation processing unit further includes an irradiation area calculation unit that calculates an irradiation area, which is an area on the surface of the virtual model that is irradiated with X-rays at the current imaging unit angle; The X-ray imaging system according to any one of items 1 to 6, wherein the display unit is configured to display a display indicating the angular region included in the irradiation region from among the plurality of angular regions in the angular dose image.

[0125] (Item 8) 8. The X-ray imaging system according to item 7, wherein the display unit is configured to identifiably display the maximum value of the dose in the angular region included in the irradiation region, separately from the angular dose image.

[0126] (Item 9) 9. The X-ray imaging system according to any one of items 1 to 8, wherein the display unit is configured to identifiably display, in the angular dose image, the angular regions for which X-ray irradiation is recommended among the plurality of angular regions.

[0127] (Item 10) further comprising an operation unit that accepts input operations by an operator; The X-ray imaging system according to any one of items 1 to 9, wherein the movement mechanism is configured to change the angle of the imaging unit when an operation to select one of the plurality of angular regions in the angular dose image is accepted by the operation unit so that X-rays are irradiated onto the selected angular region.

[0128] (Item 11) 11. The X-ray imaging system according to any one of items 1 to 10, wherein the display unit is configured to display the angular dose image in which the magnitude of the dose in each of the plurality of angular regions is represented by color-coding, and to display, separately from the angular dose image, a color scale image indicating the color coding of the plurality of angular regions in the angular dose image corresponding to the magnitude of the dose.

[0129] (Item 12) Item 12. The X-ray imaging system according to item 11, wherein the display unit is configured to identifiably display a preset dose threshold value in the color scale image.

[0130] (Item 13) a touch panel that is separate from the display unit and that displays a plurality of the image capture unit angles in a selectable manner and that accepts an input operation to change the image capture unit angle; 13. The X-ray imaging system according to any one of items 1 to 12, wherein the touch panel is configured to display the angular dose image.

[0131] (Item 14) The display unit is configured to display a three-dimensional image of the inside of the subject's body that has been acquired in advance, and to distinguishably display the dose in the angular region at the imaging unit angle that corresponds to the display angle of the displayed three-dimensional image.

[0132] (Item 15) an imaging unit including an X-ray irradiation unit having an X-ray source that irradiates X-rays onto a subject lying on a tabletop, and an X-ray detection unit that detects the X-rays irradiated from the X-ray irradiation unit, and calculating a dose distribution on the surface of a three-dimensional virtual model that represents the subject lying on the tabletop based on the dose of X-rays irradiated onto the subject; a step of associating an imaging unit angle, which is an angle of the imaging unit, with a surface of the virtual model based on the imaging unit angle and a position on the surface of the virtual model where X-rays are irradiated; calculating a dose in each of a plurality of angular regions partitioned at predetermined angular intervals of the imaging unit angle based on the calculated dose distribution on the surface of the virtual model and the imaging unit angle associated with the surface of the virtual model; and displaying an angular dose image in which the magnitude of the dose in each of the calculated plurality of angular regions can be distinguished. [Explanation of symbols]

[0133] 1 baking sheet 2. Imaging unit 3 Moving mechanism 4 Monitor (display) 5 Touch panel (operation section) 6 Control section 21 X-ray irradiation section 21a X-ray source 22 X-ray detection unit 42 angle dose images 43 Color Scale Images 43a, 43b Threshold 46 3D images 70 Dose calculation processing unit 71 Positional relationship acquisition unit 72 Model Dose Calculation Unit 73 Angle Correspondence Section 74 Angle dose calculation unit 76 Irradiation area calculation section 77 Memory Processing Unit 78 Dose Prediction Department 100 X-ray system

Claims

1. an imaging unit including an X-ray irradiator having an X-ray source that irradiates X-rays onto a subject lying on a tabletop, and an X-ray detector that detects the X-rays irradiated from the X-ray irradiator; a moving mechanism for changing an imaging unit angle, which is the angle of the imaging unit; a dose calculation processing unit that calculates the dose of X-rays irradiated to the subject; a display unit that displays the X-ray dose calculated by the dose calculation processing unit, The dose calculation processing unit a model dose calculation unit that calculates a dose distribution on a surface of a three-dimensional virtual model representing the subject lying on the tabletop based on the dose of X-rays irradiated onto the subject by the X-ray irradiation from the imaging unit; an angle association unit that associates the imaging unit angle with the surface of the virtual model based on the imaging unit angle and a position on the surface of the virtual model where X-rays are irradiated; an angle dose calculation unit that calculates a dose in each of a plurality of angle regions partitioned at predetermined angle intervals of the image capturing unit angle, based on the dose distribution on the surface of the virtual model calculated by the model dose calculation unit and the image capturing unit angle associated with the surface of the virtual model by the angle association unit, the display unit is configured to display an angular dose image in which the plurality of angular regions are arranged at the predetermined angular intervals, and in which the magnitude of the dose in each of the plurality of angular regions calculated by the angular dose calculation unit can be distinguished; further comprising an operation unit that accepts input operations by an operator; the moving mechanism is configured to, when the operation unit receives an operation to select one of the plurality of angular regions in the angular dose image in which the plurality of angular regions are arranged at the predetermined angular intervals, change the angle of the imaging unit so that X-rays are irradiated onto the selected angular region.

2. 2. The X-ray imaging system according to claim 1, wherein the display unit is configured to display the angular dose image in which the magnitude of the dose in each of the plurality of angular regions is represented by color-coding, and to display a color scale image, separately from the angular dose image, showing the color coding of the plurality of angular regions in the angular dose image corresponding to the magnitude of the dose.

3. The X-ray imaging system according to claim 2 , wherein the display unit is configured to identifiably display a preset dose threshold value in the color scale image.

4. a touch panel that is separate from the display unit and that displays a plurality of the image capture unit angles in a selectable manner and that accepts an input operation to change the image capture unit angle; The radiography system of claim 1 , wherein the touch panel is configured to display the angular dose image.

5. 2. The X-ray imaging system according to claim 1, wherein the display unit is configured to display a three-dimensional image of the inside of the subject's body that has been acquired in advance, and to distinguishably display the dose in the angular region at the imaging unit angle that corresponds to the display angle of the displayed three-dimensional image.

Images