JP2019042389A - Radiation therapy apparatus and patient positioning apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce an exposure dose by X-ray imaging for patient positioning in a period immediately before radiotherapy. A radiotherapy apparatus includes an irradiation unit, a sleeper, a first X-ray imaging system, a second X-ray imaging system, a storage unit, and a determination unit. The irradiation unit irradiates the subject to be treated with therapeutic radiation. The sleeper movably supports the top plate on which the subject is placed. The first X-ray imaging system includes a first X-ray tube and a first X-ray detector for X-ray imaging of a subject placed on a top plate. The second X-ray imaging system has a second X-ray tube and a second X-ray detector for X-ray imaging of the subject placed on the top plate. The storage unit stores a three-dimensional medical image of the subject. The determination unit makes it possible for each of the first X-ray imaging system and the second X-ray imaging system to meet a preset standard for the dose of X-rays transmitted through the subject based on a three-dimensional medical image. Determine at least one of the shooting direction and the aperture of the aperture. [Selection diagram] Fig. 1

Description

  Embodiments of the present invention relate to a radiation treatment device and a patient positioning device.

  Patient positioning is performed in radiation therapy. As a method of positioning a patient, there is a method using a radiotherapy device synchronizer. In this method, the patient is X-rayed in two directions by the radiotherapy device synchronizer in the pre-treatment period to generate X-ray images, and the X-ray image immediately before the treatment is used as a bone between the patient image at the treatment planning The position of the base is adjusted to calculate the amount of displacement, and the patient is aligned according to the amount of displacement. However, the imaging direction of the radiotherapy apparatus synchronizer is limited to a narrow range, and there is a possibility that X-rays may be irradiated to a normal area that is largely deviated from the treatment area.

JP, 2015-186537, A JP 2005-305048 A

  The problem to be solved by the invention is to reduce the X-ray exposure dose for patient positioning immediately before radiation treatment.

  The radiation treatment apparatus according to the present embodiment includes an irradiation unit configured to irradiate treatment radiation to a subject subjected to radiation treatment, a bed configured to movably support a top plate on which the subject is placed, and the top plate. A first X-ray imaging system having a first X-ray tube and a first X-ray detector for X-ray imaging the placed object; and the object placed on the top plate A second X-ray imaging system having a second X-ray tube for X-raying a sample and a second X-ray detector; a storage unit for storing a three-dimensional medical image of the subject; In each of the first X-ray imaging system and the second X-ray imaging system, imaging such that the dose of X-rays transmitted through the subject based on the three-dimensional medical image satisfies a preset reference And a determination unit that determines at least one of the direction and the aperture of the aperture.

FIG. 1 is a view showing the configuration of a radiation treatment apparatus according to the first embodiment. FIG. 2 is a view showing the appearance of the X-ray imaging system, the gantry and the bed shown in FIG. FIG. 3 is a diagram showing a typical flow of processing of the radiation treatment apparatus according to the first embodiment. FIG. 4 is a diagram showing an example of setting of the imaging margin to the DRR image in step S2 of FIG. FIG. 5 is a diagram showing an example of setting of an important organ area in the DRR image in step S3 of FIG. FIG. 6 is a view showing an example of calculation of the aperture value of the X-ray stop in step S4 of FIG. FIG. 7 is a view showing a calculation example of the aperture value of the X-ray iris when the important organ area is included in the imaging margin in step S4 of FIG. FIG. 8 is a diagram showing the details of the calculation of the transmitted X-ray dose in step S5 of FIG. FIG. 9 is a view showing a display screen of an imaging direction for patient positioning imaging in step S7 of FIG. FIG. 10 is a view showing the configuration of a patient positioning device according to the second embodiment.

  Hereinafter, a radiation treatment apparatus and a patient positioning apparatus according to the present embodiment will be described with reference to the drawings.

First Embodiment
The radiation treatment apparatus 1 according to the first embodiment is a radiation treatment apparatus equipped with a patient positioning device. The patient positioning device is a device for positioning a patient performed immediately before the treatment using an X-ray imaging system. The patient positioning device is also referred to as a radiotherapy device synchronizer.

  FIG. 1 is a diagram showing the configuration of the radiation treatment apparatus 1 according to the first embodiment. As shown in FIG. 1, the radiation treatment apparatus 1 has an X-ray imaging system 10, a gantry 30, a bed 50 and a console 70.

  FIG. 2 is a view showing the appearance of the X-ray imaging system 10, the gantry 30 and the bed 50 of FIG. As shown in FIGS. 1 and 2, the gantry 30 has a fixed portion 31 and a rotating portion 32. The fixed portion 31 is installed on the floor and supports the rotating portion 32 rotatably around the rotation axis. The irradiation head 321 is provided in a part of the rotating unit 32, and the irradiation head 321 incorporates the irradiator 33. The irradiator 33 mounts, for example, a metal target with which the electrons transported by the accelerating tube collide. The collision of electrons with the metal target generates X-rays as radiation. The irradiation head 321 is provided with a multi leaf collimator (MLC: Multi Leaf Collimator). The multileaf collimator individually movably supports a plurality of leaves formed by the X-ray shielding material. It is possible to form a radiation field of any shape by moving a plurality of leaves. An intersection point connecting the central axis of the radiation emitted from the irradiator 33 and the rotation axis of the rotating unit 32 is called an isocenter IS.

  The irradiation system control circuit 35 supplies an irradiation signal to the irradiator 33 in accordance with a command from the treatment system control circuit 73 of the console 70. The irradiator 33 receiving the irradiation signal irradiates the patient P with radiation. Further, the irradiation system control circuit 35 supplies a drive signal to the multileaf collimator in accordance with a command from the treatment system control circuit 73. The multi-leaf collimator supplied with the drive signal moves the plurality of leaves to form a designated radiation field.

  The gantry drive device 34 is incorporated in, for example, the fixing unit 31. The gantry drive device 34 receives the drive signal from the gantry control circuit 36 and rotates the rotating unit 32. The gantry control circuit 36 supplies a drive signal to the gantry driving device 34 in accordance with a command from the treatment system control circuit 73 of the console 70.

  The X-ray imaging system 10 is equipped with an X-ray imaging mechanism for X-ray imaging a patient P to be subjected to radiation treatment. The X-ray imaging system 10 according to the present embodiment is equipped with a two-system X-ray imaging system including a first X-ray imaging system 11 and a second X-ray imaging system 12. The X-ray imaging system 10 performs X-ray imaging of the patient P placed on the top plate 52 of the bed 50 in the first imaging direction by the first X-ray imaging system 11, and the second X-ray imaging system 12 The X-ray imaging is performed in the second imaging direction. More specifically, the X-ray imaging system 10 includes a first X-ray imaging system 11, a first moving mechanism 13, a first moving drive device 15, a second X-ray imaging system 12, a second moving mechanism 14, and a second 2 has a moving drive 16.

  The first X-ray imaging system 11 includes a first X-ray tube 111, a first X-ray stop 112, and a first X-ray detector 113. The first X-ray tube 111 generates X-rays. The first X-ray stop 112 is an aperture variable X-ray stop attached to the first X-ray tube 111. The first X-ray detector 113 detects X-rays generated from the first X-ray tube 111 and transmitted through the patient P, and generates X-ray image data.

  The first moving mechanism 13 supports each of the first X-ray tube 111 and the first X-ray detector 113 movably on a predetermined arc, with the first X-ray tube 111 and the first X-ray detector 113 as a pair. . Specifically, the first moving mechanism 13 has a moving mechanism 131 for the first X-ray tube 111 and a moving mechanism 132 for the first X-ray detector 113. The moving mechanism 131 has, for example, a linear motion guide, a ball screw or the like which is embedded in the floor surface 100 of the treatment room and movably supports the first X-ray tube 111 on a predetermined arc. The moving mechanism 132 is attached to, for example, the ceiling 200 of the treatment room, and has a linear motion guide, a ball screw, and the like that support the first X-ray detector 113 movably on a predetermined arc. For example, the first X-ray tube 111 is moved to the moving mechanism 131 so that the imaging axis A1 connecting the focal point of the first X-ray tube 111 and the detection surface center of the first X-ray detector 113 intersects the isocenter IS. The detector 113 is supported by the moving mechanism 132.

  The first mobile drive unit 15 synchronously drives both moving mechanisms 131 and 132 according to a command from the X-ray imaging system control circuit 72 of the console 70 so that the first X-ray tube 111 and the first X-ray detector 113 are always positive. Move to the opposite side. The imaging direction of the first X-ray imaging system 11 is defined by the angle of the imaging axis A1 around the isocenter IS.

  The second X-ray imaging system 12 includes a second X-ray tube 121, a second X-ray stop 122, and a second X-ray detector 123. The second X-ray tube 121 generates X-rays. The second X-ray stop 122 is a variable X-ray stop attached to the second X-ray tube 121. The second X-ray detector 123 detects X-rays generated from the second X-ray tube 121 and transmitted through the patient P, and generates X-ray image data.

  The second moving mechanism 14 supports the second X-ray tube 121 and the second X-ray detector 123 so as to be movable on a predetermined arc. Specifically, the second moving mechanism 14 has a moving mechanism 141 for the second X-ray tube 121 and a moving mechanism 142 for the second X-ray detector 123. The moving mechanism 141 has, for example, a linear motion guide, a ball screw or the like which is embedded in the floor surface 100 of the treatment room and movably supports the second X-ray tube 121 on a predetermined arc. The moving mechanism 142 is attached to, for example, the ceiling 200 of the treatment room, and has a linear motion guide, a ball screw or the like that supports the second X-ray detector 123 movably on a predetermined arc. For example, the second X-ray tube 121 sends the second X-ray to the moving mechanism 141 so that the imaging axis A2 connecting the focal point of the second X-ray tube 121 and the detection surface center of the second X-ray detector 123 intersects the isocenter IS. The detector 123 is supported by the moving mechanism 142.

  The second mobile drive unit 16 synchronously drives both moving mechanisms 141 and 142 in accordance with a command from the X-ray imaging system control circuit 72 of the console 70 so that the second X-ray tube 121 and the second X-ray detector 123 are always positive. Move to the opposite side. The imaging direction of the second X-ray imaging system 12 is defined by the angle of the imaging axis A2 around the isocenter IS.

  The movement range of the first X-ray tube 111 and the first X-ray detector 113 and the movement range of the second X-ray tube 121 and the second X-ray detector 123 are usually narrower than all directions around the isocenter IS. Therefore, the degrees of freedom regarding the imaging directions of the first X-ray imaging system 11 and the second X-ray imaging system 12 are relatively limited.

  The bed 50 has a base 51 and a top 52. The base 51 is installed on the floor of the treatment room and supports the top 52 movably. The top 52 has a substantially planar shape, on which the patient is placed.

  As shown in FIG. 1, the console 70 includes a processing circuit 71, an X-ray imaging system control circuit 72, a treatment system control circuit 73, a storage circuit 74, a display circuit 75, an input circuit 76, and a communication circuit 77. The processing circuit 71, the X-ray imaging system control circuit 72, the treatment system control circuit 73, the storage circuit 74, the display circuit 75, the input circuit 76, and the communication circuit 77 are communicably connected to each other via a bus.

  The processing circuit 71 includes, as hardware resources, a processor such as a central processing unit (CPU) or a graphics processing unit (GPU) and a memory such as a read only memory (ROM) or a random access memory (RAM). Specifically, the processing circuit 71 includes a DRR image generation function 711, an imaging margin setting function 712, an important organ setting function 713, an aperture opening determination function 714, an imaging direction determination function 715, a display control function 716, and a synchronization signal generation function 717. Have. The processing circuit 71 may be realized by an application specific integrated circuit (ASIC), a field programmable gate array (FPGA), a complex programmable logic device (CPLD), or a simple programmable logic device (SPLD) capable of realizing the above functions. .

  In the DRR image generation function 711, the processing circuit 71 generates a plurality of DRR images regarding a plurality of gaze directions based on the three-dimensional medical image. The three-dimensional medical image is an image that represents three-dimensional morphological information of the subject, and is generated by, for example, an X-ray computed tomography apparatus for treatment planning. Hereinafter, it is assumed that the three-dimensional medical image is a three-dimensional CT image for treatment planning. The DRR image is a two-dimensional image that simulates an X-ray image captured by an X-ray diagnostic apparatus. The processing circuit 71 includes a plurality of DRR images regarding a plurality of imaging directions that can be imaged by the first X-ray imaging system 11 and a plurality of DRR images regarding a plurality of imaging directions that can be imaged by the second X-ray imaging system 12 Generate

  In the imaging margin setting function 712, the processing circuit 71 sets an imaging margin for each DRR image generated by the DRR image generation function 711. The imaging margin is a radiation area including the treatment site.

  In the important organ setting function 713, the processing circuit 71 sets an important organ area for each DRR image generated by the DRR image generation function 711. An important organ area is an image area that is relatively sensitive to radiation and that corresponds to an organ that should avoid radiation.

  In the diaphragm opening determination function 714, the processing circuit 71 determines the dose of X-rays transmitted through the patient P based on the three-dimensional medical image for each of the first X-ray imaging system 11 and the second X-ray imaging system 12 Determine the aperture of the stop that meets the preset criteria.

  In the imaging direction determination function 715, the processing circuit 71 determines that the dose of X-rays transmitted through the patient P satisfies a preset reference for each of the first X-ray imaging system 11 and the second X-ray imaging system 12. Such imaging directions are determined based on the three-dimensional medical image. The determined imaging direction is set to the imaging direction for patient positioning. Specifically, the processing circuit 71 calculates a plurality of transmitted X-ray doses with respect to a plurality of imaging directions in which each of the X-ray imaging systems 11 and 12 can be disposed. Of the plurality of transmitted X-rays, an imaging direction corresponding to the transmitted X-ray meeting the preset criteria is determined as the imaging direction for patient positioning. The transmitted X-ray dose meeting the preset criteria is, for example, the smallest transmitted X-ray dose among the plurality of transmitted X-ray doses. The transmitted X-ray dose satisfying the preset criteria according to the present embodiment is not limited to the minimum transmitted X-ray dose, but may be the second smallest transmitted X-ray dose or transmitted X-ray dose of any order. Further, the transmitted X-ray dose satisfying the preset criteria according to the present embodiment is not limited to only the order, and the imaging direction or the like may be considered.

  In the display control function 716, the processing circuit 71 displays the imaging directions determined by the imaging direction determination function 715 in a predetermined layout for each of the first X-ray imaging system 11 and the second X-ray imaging system 12. .

  In the synchronization signal generation function 717, the processing circuit 71 irradiates radiation by the irradiator 33 based on the X-ray image acquired by each of the first X-ray imaging system 11 and the second X-ray imaging system 12. To generate an ON signal and an OFF signal for stopping irradiation of radiation.

  The X-ray imaging system control circuit 72 controls the X-ray imaging system 10 in order to position the patient in the period immediately before radiation treatment. Specifically, the X-ray imaging system control circuit 72 controls the first mobile drive device 15 in order to arrange the first X-ray imaging system 11 in a predetermined imaging direction. The X-ray imaging system control circuit 72 controls the first X-ray tube 111 to perform X-ray imaging with the first X-ray imaging system 11. The X-ray imaging system control circuit 72 controls the first X-ray stop 112 in order to limit the irradiation field of X-rays irradiated from the first X-ray tube 111. Similarly, the X-ray imaging system control circuit 72 controls the second mobile drive unit 16 to arrange the second X-ray imaging system 12 in a predetermined imaging direction, and the second X-ray imaging system 12 performs X-ray imaging. The second X-ray tube 121 is controlled to perform radiography, and the second X-ray stop 122 is controlled to limit the X-ray irradiation field irradiated from the second X-ray tube 121.

  The treatment system control circuit 73 controls the irradiation system control circuit 35 and the gantry control circuit 36 in order to irradiate the patient P with radiation during radiation treatment. The treatment system control circuit 73 controls the irradiation system control circuit 35 so as to irradiate radiation in response to the generation of the ON signal by the synchronization signal generation function 717. The treatment system control circuit 73 controls the irradiation system control circuit 35 so as to stop the radiation triggered by the generation of the OFF signal by the synchronization signal generation function 717. The treatment system control circuit 73 controls the gantry control circuit 36 to position the irradiation head 321 in the irradiation direction according to the treatment plan.

  The storage circuit 74 is a storage device such as a hard disk drive (HDD), a solid state drive (SSD), an integrated circuit storage device, or the like that stores various information. For example, the storage circuit 74 stores a treatment plan supplied from a treatment planning device or the like and a three-dimensional CT image for treatment plan. The storage circuit 74 as hardware may be a drive device or the like that reads and writes various information from and to a portable storage medium such as a CD-ROM drive, a DVD drive, or a flash memory.

  The display circuit 75 displays various information. Specifically, the display circuit 75 has a display interface and a display device. The display interface converts data representing a display target into a video signal. The video signal is supplied to the display device. The display device displays a video signal representing a display target. As a display device, for example, a CRT display, a liquid crystal display, an organic EL display, an LED display, a plasma display, or any other display known in the art can be appropriately used.

  Specifically, the input circuit 76 has an input device and an input interface. The input device receives various commands from the user. As an input device, a keyboard, a mouse, various switches and the like can be used. The input interface supplies an output signal from an input device to the processing circuit 71 via a bus.

  The communication circuit 77 performs data communication with another device such as a treatment planning device (not shown) or a radiotherapy information system (OIS) such as a wired or wireless communication.

  Hereinafter, an operation example of the radiation treatment apparatus 1 will be described in the first embodiment.

  FIG. 3 is a diagram showing a typical flow of processing of the radiation treatment apparatus 1 according to the first embodiment. As shown in FIG. 3, the processing circuit 71 first executes the DRR image generation function 711 (step S1). In step S1, the processing circuit 71 generates a plurality of DRR images for a plurality of imaging directions based on the three-dimensional CT image for treatment planning for each of the first X-ray imaging system 11 and the second X-ray imaging system 12. Generate For example, DRR images are generated every 1 ° over the movement range of the X-ray tubes 111 and 121 and the X-ray detectors 113 and 123.

  When step S1 is performed, the processing circuit 71 executes an imaging margin setting function 712 (step S2). In step S2, the processing circuit 71 sets a shooting margin for each DRR image generated in step S1.

  FIG. 4 is a view showing a setting example of the imaging margin RM to the DRR image I1. As shown in FIG. 4, the DRR image I1 includes the treatment site RT. The user designates the image area of the imaging margin RM via the input circuit 76 so as to include the treatment site RT. The processing circuit 71 sets the image area designated by the user via the input circuit 76 as the photographing margin RM. The processing circuit 71 may perform image processing on the DRR image I1 to recognize the treatment site RT, and may automatically set the imaging margin RM so as to include the treatment site RT.

  When step S2 is performed, the processing circuit 71 executes the important organ setting function 713 (step S3). In step S3, the processing circuit 71 sets an important organ area in each DRR image generated in step S1.

  FIG. 5 is a diagram showing an example of setting of the important organ area RR in the DRR image I2. As shown in FIG. 5, the user designates the image area of the important organ RR via the input circuit 76. The processing circuit 71 sets the image area designated by the user via the input circuit 76 as the important organ area RR. The processing circuit 71 may perform image processing on the DRR image I2 to recognize the important organ RR, and may automatically set an image region corresponding to the important organ as the important organ region RR.

  When step S3 is performed, the processing circuit 71 executes the aperture opening determination function 714 (step S4). In step S4, the processing circuit 71 calculates the aperture value of the first X-ray stop 113 or the second X-ray stop 123 for each of a plurality of imaging directions corresponding to a plurality of DRR images. The aperture value is constituted by the position of each X-ray blocking plate that defines the apertures of the X-ray squeezers 113 and 123.

  FIG. 6 is a view showing a calculation example of the aperture values of the X-ray stop devices 113 and 123. As shown in the upper part of FIG. 6, a shooting margin RM3 is set for each DRR image I3. As shown in the lower part of FIG. 6, the processing circuit 71 is such that the X-ray irradiation range defined by the plurality of X-ray blocking plates 81 and 83 constituting the X-ray stop 113 and 123 is limited to the imaging margin RM3. Calculate the aperture value. The X-ray stop devices 113 and 123 mount, for example, two pairs of X-ray blocking plates 81 and 83 intersecting each other. A pair of X-ray shields 81 is provided slidably along a longitudinal axis in a plane perpendicular to the imaging axis, and the remaining pair of X-ray shields 83 are arranged along a horizontal axis in the plane. It is provided slidably. For example, the processing circuit 71 calculates the positions of the X-ray blocking plates 81 and 83 such that the imaging margin RM is inscribed in the X-ray irradiation range defined by the plurality of X-ray blocking plates 81 and 83. The combination of the calculated positions of the X-ray blocking plates 81 and 83 is set as the aperture value.

  FIG. 7 is a diagram showing an example of calculation of the aperture values of the X-ray stop devices 112 and 122 when the important organ area RR is included in the imaging margin RM. As shown in the upper part of FIG. 7, when the important organ area RR4 is set to overlap the imaging margin RM4 in the DRR image I4, the processing circuit 71 realizes the X-ray irradiation range not including the important organ area RR4. Calculate the opening value.

  Specifically, first, the processing circuit 71 determines by image processing whether or not the important organ area RR4 overlaps the imaging margin RM4 in the DRR image I4. As shown in FIG. 6, when the important organ area RR4 does not overlap with the imaging margin RM4, the processing circuit 71 limits the imaging margin RM4 to the X-ray squeezing devices 113 and 123 which irradiate X-rays. Calculate the aperture value. As shown in the lower part of FIG. 7, when the important organ area RR4 overlaps with the imaging margin RM4, the processing circuit 71 does not irradiate the relevant organ area RR4 with the X-ray, and the X-ray is in the imaging margin RM4. The positions of the X-ray shielding plates 81 and 83 to be irradiated are calculated. The combination of the calculated positions of the X-ray blocking plates 81 and 83 is set to the aperture value of the X-ray squeezers 113 and 123.

  In addition, a multileaf collimator may be used as the X-ray stop 113, 123. In this case, the shape of the X-ray irradiation range can be made more consistent with the shape of the imaging margin RM. The calculation method of the aperture value is the same as the above-mentioned method using the usual X-ray stop 113, 123. That is, the processing circuit 71 calculates the position of each leaf such that the X-ray irradiation range defined by the plurality of leaves constituting the multi-leaf collimator is inscribed in the imaging margin RM. The combination of the positions of the calculated leaves is set as the aperture value.

  When step S4 is performed, the processing circuit 71 executes an imaging direction determination function (step S5). In step S5, the processing circuit 71 calculates the transmitted X-ray dose of the patient for each of a plurality of imaging directions corresponding to a plurality of DRR images.

  FIG. 8 is a diagram showing the details of the calculation of the transmitted X-ray dose. As shown in FIG. 8, the processing circuit 71 calculates the transmitted X-ray dose based on the imaging margin RM and the patient body contour RP. Specifically, the processing circuit 71 sets the outer contour RX of the X-ray to be irradiated and the patient body contour RP limited to the imaging margin RM in each imaging direction in the three-dimensional CT image I5 for treatment planning. Although the three-dimensional CT image I5 for treatment planning is two-dimensionally shown in FIG. 8, it is actually three-dimensional.

  When the X-ray outer contour RX and the patient body contour RP are set, the processing circuit 71 encloses the X-ray outer contour RX and the patient body contour RP among the pixels constituting the three-dimensional CT image I5 for treatment planning. The number of pixels (number of voxels) of the pixels constituting the image region RV to be calculated is counted as the transmitted X-ray dose. When the important organ area RR is included in the imaging margin RM, the pixel count of the image area excluding the important organ area RR from the image area RV surrounded by the X-ray outer contour RX and the patient body contour RP It may be counted as the transmitted X-ray dose.

  When step S5 is performed, the processing circuit 71 continues to execute the photographing direction determination function 715 (step S6). In step S6, the processing circuit 71 is the smallest of the plurality of transmitted X-ray doses in the plurality of imaging directions calculated in step S5 for each of the first X-ray imaging system 11 and the second X-ray imaging system 12 The transmission X-ray dose of X. is determined, and the imaging direction corresponding to the minimum transmission X-ray dose is determined as the imaging direction for patient positioning imaging. Further, the aperture value for the patient positioning imaging among the plurality of aperture values for the plurality of imaging directions calculated in step S4 is determined by the aperture opening determining function 714 as the patient positioning imaging aperture value. .

  When step S6 is performed, the processing circuit 71 executes the display control function 716 (step S7). In step S7, the processing circuit 71 causes the display circuit 75 to display the imaging direction for patient positioning imaging determined in step S6.

  FIG. 9 is a view showing a display screen I6 in the imaging direction for patient positioning imaging. As shown in FIG. 9, the imaging directions for patient positioning imaging are displayed for each of the first X-ray imaging system 11 and the second X-ray imaging system 12. Specifically, the display screen I6 is a display field R1 for imaging direction for patient positioning imaging regarding the first X-ray imaging system 11 and a display field for imaging direction for patient positioning imaging regarding the second X-ray imaging system 12 And R2. For example, “115 °” is displayed in the display field R1 as the imaging direction for patient positioning imaging related to the first X-ray imaging system 11. In the display field R2, “236 °” is displayed as an imaging direction for patient positioning imaging related to the second X-ray imaging system 12. The imaging direction for patient positioning imaging is not limited to being represented by numbers, and the positions of the first X-ray imaging system 11 and the second X-ray imaging system 12 and the patient in the imaging direction for patient positioning imaging The relationships may be displayed graphically. In addition, the processing circuit 71 displays, for each of the first X-ray imaging system 11 and the second X-ray imaging system 12, the aperture value for patient positioning imaging determined by the diaphragm aperture determination function 714. Also good.

  When step S7 is performed, the X-ray imaging system control circuit 72 performs X-ray imaging for patient positioning (step S8). In step S8, the X-ray imaging system control circuit 72 controls the first mobile drive unit 15 and the second mobile drive unit 16, and the first X-ray imaging in the imaging direction for patient positioning imaging determined in step S6. Each of the system 11 and the second X-ray imaging system 12 is arranged. In addition, the X-ray imaging system control circuit 72 controls the first X-ray stop 112 and the second X-ray stop 122, and the aperture value of the first X-ray stop 112 is determined for patient positioning imaging determined in step S6. The aperture value of the second X-ray stop 122 is set to the aperture value for patient positioning imaging determined in step S6. Then, the X-ray imaging system control circuit 72 controls the first X-ray tube 111 and the second X-ray tube 112 to perform X-ray imaging from two directions. Thereby, patient positioning imaging can be performed with a small X-ray exposure dose.

  When step S8 is performed, patient positioning is performed (step S9). For example, the positional deviation amount is calculated with the treatment plan three-dimensional CT image, and the patient P on the top 52 is moved or the top 52 is moved so that the positional deviation becomes approximately zero. .

  When step S9 is performed, the treatment system control circuit 73 performs radiation treatment (step S10). In step S10, the treatment system control circuit 73 synchronously controls the irradiation system control circuit 35 and the gantry control circuit 36 so as to perform radiation treatment according to the treatment plan. Thereby, the patient P can be irradiated with radiation with accurate positioning.

  This is the end of the description of the process of the radiation treatment apparatus 1 according to the first embodiment.

  In addition, the flow of a process of said radiotherapy apparatus 1 is an example, and this embodiment is not limited to this. For example, in the above process flow, although both the imaging direction for patient positioning imaging and the aperture value of the X-ray diaphragm are determined, the imaging direction and X may be determined according to the degree of freedom of movement of the X-ray imaging system 10. One of the aperture values of the linear stop may not be determined. For example, the imaging directions of the first X-ray tube 111 and the first X-ray detector 113 of the first X-ray imaging system 11 and the second X-ray tube 121 and the second X-ray detector 123 of the second X-ray imaging system 12 are If it is fixed, the imaging direction for patient positioning imaging may not be determined. In this case, only the aperture values of the X-ray stop devices 112 and 122 in the fixed imaging direction are determined by the stop aperture determination function 714. The imaging directions of the first X-ray tube 111 and the first X-ray detector 113 of the first X-ray imaging system 11 and the second X-ray tube 121 and the second X-ray detector 123 of the second X-ray imaging system 12 are When movable as in the above embodiment, both the imaging direction and aperture value for patient positioning imaging are determined.

  In the above description, after the aperture value has been calculated for each imaging direction in step S4, the transmitted X-ray dose is calculated for each imaging direction in step S5. However, the aperture value and the transmitted X-ray dose may be calculated in parallel for each imaging direction.

  As described above, the movement range of the first X-ray tube 111 and the first X-ray detector 113 and the movement range of the second X-ray tube 121 and the second X-ray detector 123 are usually narrower than all directions around the isocenter IS, The degrees of freedom regarding the imaging directions of the first X-ray imaging system 11 and the second X-ray imaging system 12 are relatively limited. Therefore, in the conventional apparatus, it is difficult to localize an X-ray for positioning in the period immediately before radiation treatment to the treatment site depending on the patient position and the treatment site position. In such a case, the normal site will be radiographed along with the treatment site, but the exposure to the normal site should be reduced.

  As described above, the radiotherapy apparatus 1 according to the first embodiment includes the irradiator 33, the bed 50, the first X-ray imaging system 11, the second X-ray imaging system 12, the storage circuit 74, and the processing circuit 71. . The irradiator 33 applies therapeutic radiation to the patient P to be subjected to radiation treatment. The bed 50 movably supports a top on which the patient P is placed. The first X-ray imaging system 11 has a first X-ray tube 111 and a first X-ray detector 113 for performing X-ray imaging of the patient P placed on the top 52. The second X-ray imaging system 12 has a second X-ray tube 121 and a second X-ray detector 123 for performing X-ray imaging of the patient P placed on the top 52. The storage circuit 74 stores a three-dimensional medical image for treatment planning on the patient P. The processing circuit 71 sets, for each of the first X-ray imaging system 11 and the second X-ray imaging system 12, the dose of X-rays transmitted through the patient P based on the three-dimensional medical image for treatment planning in advance. At least one of the imaging direction and the aperture of the aperture that satisfies the above criteria is determined.

  With the above configuration, the processing circuit 71 determines at least one of the imaging direction with a small amount of transmitted X-ray dose and the aperture of the diaphragm for each of the first X-ray imaging system 11 and the second X-ray imaging system 12 by simulation. can do. Therefore, the exposure dose of the patient P can be reduced in the patient positioning immediately before the radiotherapy by the X-ray imaging system from two directions.

Second Embodiment
In the first embodiment, the patient positioning device is incorporated in the radiation treatment apparatus 1. However, the present embodiment is not limited to this. The patient positioning device according to the second embodiment is separate from the radiation therapy device. Hereinafter, a patient positioning device according to a second embodiment will be described. In the following description, components having substantially the same functions as those of the present embodiment are denoted by the same reference numerals, and redundant descriptions will be made only when necessary.

  FIG. 10 is a diagram showing the configuration of a patient positioning device 1 'according to the second embodiment. As shown in FIG. 10, the patient positioning apparatus 1 'has an X-ray imaging system 10 and a console 70. The patient positioning device 1 'is communicably connected to a radiotherapy device (not shown). The X-ray imaging system 10 and the bed 50 are installed in a treatment room as in the case of the radiation treatment apparatus.

  As described above, the patient positioning apparatus 1 'according to the second embodiment includes the first X-ray imaging system 11, the second X-ray imaging system 12, the storage circuit 74, and the processing circuit 71. The first X-ray imaging system 11 has a first X-ray tube 111 and a first X-ray detector 113 for performing X-ray imaging of the patient P placed on the top. The second X-ray imaging system 12 has a second X-ray tube 121 and a second X-ray detector 123 for performing X-ray imaging of the patient P placed on the top 52. The storage circuit 74 stores a three-dimensional medical image for treatment planning on the patient P. The processing circuit 71 sets, for each of the first X-ray imaging system 11 and the second X-ray imaging system 12, the dose of X-rays transmitted through the patient P based on the three-dimensional medical image for treatment planning in advance. At least one of the imaging direction and the aperture of the aperture that satisfies the above criteria is determined.

  Therefore, the patient positioning apparatus 1 'according to the second embodiment is the same as the radiotherapy apparatus 1 according to the first embodiment, for each of the first X-ray imaging system 11 and the second X-ray imaging system 12, At least one of the imaging direction in which the transmitted X-ray dose is small and the aperture of the diaphragm can be determined by simulation. Therefore, the exposure dose of the patient P can be reduced in the patient positioning immediately before the radiotherapy by the X-ray imaging system from two directions.

  As described above, according to at least one embodiment described above, it is possible to reduce an X-ray exposure dose for patient positioning in a period immediately before radiation treatment.

  While certain embodiments of the present invention have been described, these embodiments have been presented by way of example only, and are not intended to limit the scope of the invention. These novel embodiments can be implemented in various other forms, and various omissions, substitutions, and modifications can be made without departing from the scope of the invention. These embodiments and modifications thereof are included in the scope and the gist of the invention, and are included in the invention described in the claims and the equivalent scope thereof.

  DESCRIPTION OF SYMBOLS 1 ... Radiotherapy apparatus, 10 ... X-ray imaging system, 11 ... 1st X-ray imaging system, 12 ... 2nd X-ray imaging system, 13 ... 1st moving mechanism, 14 ... 2nd moving mechanism, 15 ... 2nd DESCRIPTION OF SYMBOLS 1 movement drive device, 16 ... 2nd movement drive device, 30 ... gantry, 31 ... fixed part, 32 ... rotation part, 33 ... irradiator, 34 ... gantry drive device, 35 ... irradiation system control circuit, 36 ... gantry control circuit , 50: bed, 51: base, 52: top plate, 70: console, 71: processing circuit, 72: X-ray imaging system control circuit, 73: therapeutic system control circuit, 74: storage circuit, 75: display circuit, DESCRIPTION OF SYMBOLS 76 ... Input circuit, 77 ... Communication circuit, 100 ... Floor surface, 111 ... 1st X-ray tube, 112 ... 1st X-ray iris diaphragm, 113 ... 1st X-ray detector, 121 ... 2nd X-ray tube, 122 ... 2nd X-ray Aperture, 123 ... second X-ray detector, 200 ... ceiling, 321 ... irradiation head 711 ... image generating function, 712 ... imaging margin setting function, 713 ... vital organs setting function, 714 ... aperture stop determining function, 715 ... imaging direction determining function, 716 ... display control function, 717 ... sync signal generation function.

Claims (11)

An irradiation unit that irradiates therapeutic radiation to a subject to be subjected to radiation treatment;
A bed movably supporting a top on which the subject is placed;
A first X-ray imaging system having a first X-ray tube and a first X-ray detector for X-ray imaging the subject placed on the top plate;
A second X-ray imaging system having a second X-ray tube and a second X-ray detector for X-ray imaging the subject placed on the top plate;
A storage unit configured to store a three-dimensional medical image of the subject;
In each of the first X-ray imaging system and the second X-ray imaging system, a dose of X-rays transmitted through the subject based on the three-dimensional medical image satisfies a preset reference. A determination unit that determines at least one of the shooting direction and the aperture of the aperture;
Radiation therapy apparatus comprising.   The radiation treatment apparatus according to claim 1, wherein the reference is that the dose of X-rays transmitted through the subject is minimized. A generation unit configured to generate a plurality of DRR images regarding a plurality of imaging directions based on the three-dimensional medical image for each of the first X-ray imaging system and the second X-ray imaging system;
A setting unit configured to set an X-ray irradiation range for each of the plurality of DRR images;
The determination unit determines the dose of X-rays emitted from the first X-ray imaging system or the second X-ray imaging system for each of the plurality of imaging directions, the three-dimensional medical image and the X-ray irradiation range And determining the imaging direction corresponding to the minimum dose among the plurality of imaging directions,
The radiation treatment apparatus according to claim 2. The determination unit determines the three-dimensional medical image existing in an X-ray transmission path from the first X-ray tube or the second X-ray tube to the X-ray irradiation range for each of the plurality of imaging directions. Calculate the number of pixels in the object area as a dose,
The radiation treatment apparatus according to claim 3.   5. The apparatus according to claim 4, wherein the determination unit calculates the number of pixels of the three-dimensional medical image included in the outer edge of the X-ray transmission path and the body contour of the subject region as the number of pixels in the subject region. Radiation therapy equipment.   The radiotherapy apparatus according to claim 3, wherein the setting unit sets the X-ray irradiation range in an image area other than the important organ for each of the plurality of DRR images. A generation unit configured to generate a plurality of DRR images regarding a plurality of imaging directions based on the three-dimensional medical image for each of the first X-ray imaging system and the second X-ray imaging system;
A setting unit configured to set an X-ray irradiation range for each of the plurality of DRR images;
The determination unit determines the opening based on the X-ray irradiation range for each of the plurality of imaging directions.
A radiation treatment apparatus according to claim 1. The first X-ray imaging system movably supports the first X-ray tube and the first X-ray detector, and limits an irradiation field of the first X-ray tube. It further has an X-ray stop,
The second X-ray imaging system movably supports the second X-ray tube and the second X-ray detector, and limits an irradiation field of the second X-ray tube. It further has an X-ray stop,
The determination unit determines both the imaging direction and the opening.
A radiation treatment apparatus according to claim 1. The first X-ray imaging system supports the first X-ray tube and the first X-ray detector, and limits the radiation field of the first X-ray tube. Have a bowl,
The second X-ray imaging system supports the second X-ray tube and the second X-ray detector, and limits the radiation field of the second X-ray tube Have a bowl,
The determination unit determines the opening.
A radiation treatment apparatus according to claim 1.   The radiation treatment apparatus according to claim 8 or 9, wherein the first X-ray restrictor and the second X-ray restrictor are multi-leaf collimators having a plurality of individually movable leaves. A first X-ray imaging system for supporting a first X-ray tube and a first X-ray detector for X-ray imaging a subject to be radiation treated;
A second X-ray imaging system supporting a second X-ray tube for X-ray imaging the subject and a second X-ray detector;
A storage unit configured to store a three-dimensional medical image of the subject;
In each of the first X-ray imaging system and the second X-ray imaging system, a dose of X-rays transmitted through the subject based on the three-dimensional medical image satisfies a preset reference. A determination unit that determines at least one of the shooting direction and the aperture of the aperture;
Patient positioning device comprising: