Radiation therapy device

Abstract

This radiation therapy device for treating, with radiation, an irradiation target body comprises: a treatment part having a treatment position which is the position at which the irradiation target body is treated; a mounting part on which the irradiation target body is mounted; and a position adjustment part that performs position adjustment of the irradiation target body at the mounting part. The position adjustment part performs position adjustment for adjusting the position of the irradiation target body with respect to a reference position, before the mounting part moves to the treatment position. The mounting part moves to the treatment position after completion of the position adjustment.

Description

radiation therapy equipment

[0001] The present disclosure relates to radiation therapy devices.

[0002] A conventional radiotherapy device for treating a patient using radiation is disclosed in, for example, Patent Document 1. In the radiotherapy device disclosed in Patent Document 1, a particle beam is irradiated from an irradiation unit. An MRI device is also provided at the treatment position of the patient.

[0003] Japanese Patent Application Laid-Open No. 2021-49042

[0004] In a system in which an MRI device is incorporated into a rotating gantry as described above, there is no position correction function other than that of the MRI device inside the rotating gantry. Furthermore, because the interior of the MRI device is narrow, it is difficult to correct the patient's position if the patient's position is significantly misaligned. In such cases, instead of adjusting the patient's position at the treatment position, the patient's position can be addressed by replanning the treatment plan on the spot. However, this method has the problem of requiring an extremely long treatment time.

[0005] Therefore, an object of the present disclosure is to provide a radiotherapy apparatus that can improve throughput in radiotherapy.

[0006] A radiation therapy device according to one aspect of the present disclosure is a radiation therapy device that treats an irradiated body with radiation, and includes a treatment section having a treatment position where the irradiated body is treated, a mounting section on which the irradiated body is placed, and a position adjustment section that adjusts the position of the irradiated body on the mounting section, wherein the position adjustment section adjusts the position of the irradiated body relative to a reference position before the mounting section moves to the treatment position, and the mounting section moves to the treatment position after the position adjustment is completed.

[0007] The radiation therapy device includes a treatment unit having a treatment position where treatment of the irradiated object is performed, and a mounting unit on which the irradiated object is placed. Therefore, treatment can be performed in the treatment unit by moving the irradiated object placed on the mounting unit to the treatment position. In response to this, the position adjustment unit adjusts the position of the irradiated object relative to a reference position before the mounting unit moves to the treatment position. Furthermore, the mounting unit moves to the treatment position after completing the position adjustment. This allows the position adjustment unit to adjust the position of the irradiated object before it is placed at the treatment position. This suppresses positional deviation of the irradiated object at the treatment position, eliminates the need to recalculate the treatment plan at the treatment position, and enables rapid treatment. As a result, throughput in radiation therapy can be improved.

[0008] The treatment unit includes an irradiation unit that irradiates the irradiated object with a particle beam, a rotating gantry that supports the irradiation unit so that it can rotate around the irradiated object, and a magnetic resonance imaging unit that is provided on the rotating gantry and acquires images of the irradiated object using a magnetic field. After the position adjustment is completed, the support unit may be moved to a treatment position within the magnetic resonance imaging unit. The magnetic resonance imaging unit is small, and the range of position adjustment of the irradiated object on site is limited. Therefore, the effect of performing position adjustment in advance using the position adjustment unit is more pronounced.

[0009] After the mounting unit is moved to the treatment position, the irradiated object may be positioned relative to the isocenter of the irradiation unit. The accuracy of treatment can be improved by roughly adjusting the position of the irradiated object using the position adjustment unit and then positioning the irradiated object relative to the isocenter at the treatment position.

[0010] Positioning may be performed based on the measurement results of the magnetic resonance imaging unit, thereby enabling the positioning of the irradiated object at the treatment position without providing any additional measuring device.

[0011] A first reference point that serves as a reference for treatment is set at the treatment position, and a second reference point that serves as a reference position may be set at a position different from the first reference point during position adjustment. By setting the second reference point so that position adjustment can be easily performed, it becomes possible to easily perform position adjustment using the position adjustment unit.

[0012] The radiation therapy device may further include a treatment planning device for creating a treatment plan for the radiation therapy device, the treatment planning device having a reference image indicating the position of at least the second reference point, and the reference image may be used in the position adjustment by the position adjustment unit. This allows the position adjustment by the position adjustment unit to be easily performed based on the reference image taking the treatment plan into consideration.

[0013] According to the present disclosure, it is possible to provide a radiotherapy apparatus that can improve throughput in radiotherapy.

[0014] Fig. 1 is a schematic configuration diagram showing a radiation therapy device according to an embodiment of the present disclosure; Fig. 2 is a schematic configuration diagram of the vicinity of an irradiation unit of the radiation therapy device of Fig. 1; Fig. 3 is a diagram showing layers set for a tumor; Fig. 4 is a schematic cross-sectional view showing the structure around an MRI device and a rotating gantry; Fig. 5 is a schematic front view showing the structure around an MRI device and a rotating gantry.

[0015] A radiotherapy device according to an embodiment of the present disclosure will be described below with reference to the accompanying drawings. In the description of the drawings, the same elements are denoted by the same reference numerals, and duplicated descriptions will be omitted.

[0016] FIG. 1 is a schematic configuration diagram showing a radiation therapy device 100 according to an embodiment of the present disclosure. The radiation therapy device 100 is a device that treats a patient (irradiated body) with radiation. In this embodiment, a particle beam therapy device 1 is adopted as the radiation therapy device 100. The particle beam therapy device 1 is a system used for cancer treatment using radiation therapy, etc. The particle beam therapy device 1 is a device that treats an affected area by irradiating the irradiated body with particle beams. However, the radiation therapy device 100 is not limited to a particle beam therapy device.

[0017] The particle beam therapy system 1 includes an accelerator 3 that accelerates charged particles generated by an ion source device and emits the particle beam B, an irradiation unit 2 that irradiates a patient 15 with the particle beam B, and a beam transport line 20 that transports the particle beam B emitted from the accelerator 3 to the irradiation unit 2. The irradiation unit 2 is attached to a rotating gantry 17 that surrounds a treatment table 6 and an MRI device 60. The irradiation unit 2 is rotatable by the rotating gantry 17. The irradiation unit 2 is rotatable around the treatment table 6, which is a support unit on which the patient 15 is placed, with a central axis CL as the center of rotation. The particle beam therapy system 1 also includes an MRI device 60 (MRI: Magnetic Resonance Imaging) that acquires images of the patient 15 using a magnetic field. The configurations of the accelerator 3, irradiation unit 2, beam transport line 20, and MRI device 60 will be described in more detail below.

[0018] The beam transport line 20 includes a beam duct 21 for transporting the particle beam B, an electromagnet 22 such as a quadrupole electromagnet for focusing the particle beam B, and bending electromagnets 23A, 23B, 23C, and 22D for bending the trajectory of the particle beam B. The bending electromagnets 23A and 23B bend the trajectory of the particle beam B traveling from the accelerator 3 to the rotating gantry 17 toward the outer periphery of the central axis CL. The bending electromagnets 23C and 23D, at positions spaced from the central axis CL toward the outer periphery, bend the trajectory of the particle beam B traveling toward the outer periphery of the central axis CL, and direct it toward the inner periphery. Furthermore, the bending electromagnet 23D bends the trajectory of the particle beam B so that it travels in a direction perpendicular to the central axis CL and guides it to the irradiation unit 2.

[0019] 2 is a schematic diagram of the vicinity of the irradiation unit of the particle beam therapy device 1 of FIG. 1. In the following description, the terms "X-axis direction," "Y-axis direction," and "Z-axis direction" are used. The "Z-axis direction" refers to the direction in which the base axis AX of the particle beam B extends, and is the depth direction of irradiation of the particle beam B. The "base axis AX" refers to the irradiation axis of the particle beam B when not deflected by the scanning electromagnet 50 described below. FIG. 2 shows the particle beam B being irradiated along the base axis AX. The "X-axis direction" refers to one direction in a plane perpendicular to the Z-axis direction. The "Y-axis direction" refers to a direction perpendicular to the X-axis direction in a plane perpendicular to the Z-axis direction.

[0020] First, the schematic configuration of a particle beam therapy system 1 according to this embodiment will be described with reference to Fig. 2. The particle beam therapy system 1 is an irradiation system using a scanning method. The scanning method is not particularly limited, and line scanning, raster scanning, spot scanning, etc. may be adopted. As shown in Fig. 2, the particle beam therapy system 1 includes an accelerator 3, an irradiation unit 2, a beam transport line 20, a control unit 7, an MRI device 60, a treatment planning device 90, and a storage unit 95.

[0021] The accelerator 3 is a device that accelerates charged particles and emits a particle beam B of a preset intensity. Examples of the accelerator 3 include a cyclotron and a synchrocyclotron. The accelerator 3 is connected to a control unit 7, which controls the current supplied to the accelerator 3. The particle beam B generated by the accelerator 3 is transported to the irradiation unit 2 by a beam transport line 20. The beam transport line 20 connects the accelerator 3 and the irradiation unit 2, and transports the particle beam B emitted from the accelerator 3 to the irradiation unit 2.

[0022] The irradiation unit 2 irradiates a tumor (irradiated object) 14 inside the body of a patient 15 with a particle beam B. The particle beam B is electrically charged particles accelerated to high speed, such as a proton beam, a heavy particle (heavy ion) beam, or an electron beam. Specifically, the irradiation unit 2 is a device that irradiates the tumor 14 with the particle beam B emitted from an accelerator 3 that accelerates charged particles generated by an ion source (not shown) and transported via a beam transport line 20. The irradiation unit 2 includes a scanning electromagnet 50, a quadrupole electromagnet 8, a profile monitor 11, a dose monitor 12, position monitors 13a and 13b, a collimator 40, and a degrader 30. The scanning electromagnet 50, the monitors 11, 12, 13a, and 13b, the quadrupole electromagnet 8, and the degrader 30 are housed in an irradiation nozzle 9, which serves as a housing. In this manner, the irradiation unit 2 is configured by housing each of the main components in the irradiation nozzle 9. The quadrupole electromagnet 8, the profile monitor 11, the dose monitor 12, the position monitors 13a and 13b, and the degrader 30 may be omitted.

[0023] An X-axis scanning electromagnet 50A and a Y-axis scanning electromagnet 50B are used as the scanning electromagnets 50. Each of the X-axis scanning electromagnet 50A and the Y-axis scanning electromagnet 50B is composed of a pair of electromagnets, and changes the magnetic field between the pair of electromagnets in response to a current supplied from the control unit 7 to scan the particle beam B passing between the electromagnets. The X-axis scanning electromagnet 50A scans the particle beam B in the X-axis direction, and the Y-axis scanning electromagnet 50B scans the particle beam B in the Y-axis direction. These scanning electromagnets 50 are arranged in this order on the base axis AX, downstream of the accelerator 3 from the particle beam B. The scanning electromagnets 50 scan the particle beam B so that the particle beam B is irradiated according to a scan pattern previously planned by the treatment planning device 90. How the scanning electromagnets 50 are controlled will be described later.

[0024] The quadrupole electromagnets 8 include an X-axis quadrupole electromagnet 8a and a Y-axis quadrupole electromagnet 8b. The X-axis quadrupole electromagnet 8a and the Y-axis quadrupole electromagnet 8b focus and converge the particle beam B in accordance with the current supplied from the control unit 7. The X-axis quadrupole electromagnet 8a focuses the particle beam B in the X-axis direction, and the Y-axis quadrupole electromagnet 8b focuses the particle beam B in the Y-axis direction. By changing the current supplied to the quadrupole electromagnets 8 to change the focusing amount (focusing amount), the y quadrupole electromagnet 8 can change the beam size of the particle beam B. The quadrupole electromagnets 8 are arranged on the base axis AX between the accelerator 3 and the scanning electromagnet 50 in this order. The beam size refers to the size of the particle beam B in the XY plane. The beam shape refers to the shape of the particle beam B in the XY plane.

[0025] The profile monitor 11 detects the beam shape and position of the particle beam B for alignment during initial setup. The profile monitor 11 is disposed on the base axis AX between the quadrupole electromagnet 8 and the scanning electromagnet 50. The dose monitor 12 detects the dose of the particle beam B. The dose monitor 12 is disposed on the base axis AX downstream of the scanning electromagnet 50. The position monitors 13a and 13b detect and monitor the beam shape and position of the particle beam B. The position monitors 13a and 13b are disposed on the base axis AX downstream of the particle beam B from the dose monitor 12. Each of the monitors 11, 12, 13a, and 13b outputs the detected results to the control unit 7.

[0026] The degrader 30 reduces the intensity of the passing particle beam B to finely adjust the intensity of the particle beam B. In this embodiment, the degrader 30 is provided at the tip 9 a of the irradiation nozzle 9. The tip 9 a of the irradiation nozzle 9 is the end portion on the downstream side of the particle beam B.

[0027] The collimator 40 is a member that is provided at least downstream of the scanning electromagnet 50 in the particle beam B, and blocks a part of the particle beam B and allows a part of the particle beam B to pass through. In this example, the collimator 40 is provided downstream of the position monitors 13 a and 13 b. The collimator 40 is connected to a collimator driver 51 that moves the collimator 40.

[0028] The control unit 7 is configured with, for example, a CPU, a ROM, a RAM, etc. The control unit 7 controls the accelerator 3, the scanning electromagnet 50, the quadrupole electromagnet 8, and the collimator driving unit 51 based on the detection results output from the monitors 11, 12, 13a, and 13b.

[0029] The control unit 7 of the particle beam therapy system 1 is also connected to a treatment planning device 90 that creates a treatment plan for particle beam therapy and a storage unit 95 that stores various data. The treatment planning device 90 measures the tumor 14 of the patient 15 using a CT or the like before treatment and plans a dose distribution (dose distribution of the particle beam to be irradiated) at each position on the tumor 14. Specifically, the treatment planning device 90 creates a scan pattern for the tumor 14. The treatment planning device 90 transmits the created scan pattern to the control unit 7. The scan pattern created by the treatment planning device 90 plans the scanning path and scanning speed of the particle beam B.

[0030] When irradiating with particle beams using the scanning method, the tumor 14 is virtually divided into multiple layers in the Z-axis direction, and particle beams are scanned and irradiated in one layer along a scanning path defined in the treatment plan. After irradiation of the particle beams in the one layer is completed, particle beams B are irradiated in the next adjacent layer.

[0031] When the particle beam B is irradiated by the scanning method using the particle beam therapy system 1 shown in FIG. 2, the quadrupole electromagnet 8 is activated (ON) so that the passing particle beam B is converged.

[0032] Next, particle beam B is emitted from accelerator 3. The emitted particle beam B is scanned according to the scan pattern defined in the treatment plan under the control of scanning electromagnet 50. As a result, particle beam B is irradiated while scanning within the irradiation range of one layer set in the Z-axis direction relative to tumor 14. After irradiation of one layer is completed, particle beam B is irradiated onto the next layer.

[0033] 3(a) and 3(b) will be used to explain particle beam irradiation images of the scanning electromagnet 50 in response to the control of the control unit 7. Fig. 3(a) shows an irradiated object virtually sliced ​​into multiple layers in the depth direction, and Fig. 3(b) shows a particle beam scanning image in one layer as viewed from the depth direction.

[0034] As shown in FIG. 3A, the object to be irradiated is virtually sliced ​​into a plurality of layers in the irradiation depth direction. In this example, the layers are arranged in order from the deepest layer (the longest range of the particle beam B), as follows: １ , Layer L ２ , ...Layer L ｎ－１ , Layer L ｎ , Layer L ｎ＋１ , ...Layer L Ｎ－１ , Layer L Ｎ As shown in FIG. 3B, the particle beam B is virtually sliced ​​into layers L and N while tracing a beam trajectory along a scanning path TL. In the case of continuous irradiation (line scanning or raster scanning), the particle beam B is virtually sliced ​​into layers L and N. ｎ In the case of spot scanning, the light is continuously irradiated along the scanning path TL of the layer L ｎ The particle beam B is irradiated onto a plurality of irradiation spots. The particle beam B is irradiated along a scanning path TL1 extending in the X-axis direction, shifted slightly in the Y-axis direction along a scanning path TL2, and then irradiated along the adjacent scanning path TL1. In this way, the particle beam B emitted from the irradiation unit 2 controlled by the control unit 7 moves on the scanning path TL.

[0035] Next, the MRI apparatus 60 and the rotating gantry 17 will be described with reference to FIGS. 4 and 5. FIG. 4 is a schematic cross-sectional view showing the structure around the MRI apparatus 60 and the rotating gantry 17. FIG. 5 is a schematic front view showing the structure around the MRI apparatus 60 and the rotating gantry 17. As shown in FIG. 4, the MRI apparatus 60 is mounted on the rotating gantry 17 together with the irradiation unit 2. The MRI apparatus 60 can be rotated around the treatment table 6 by the rotating gantry 17, with the central axis CL as the center of rotation. The MRI apparatus 60 includes multiple coils 61 (a pair in FIG. 1) that are sources of magnetic fields. The MRI apparatus 60 is a passive shield type apparatus that returns magnetic flux generated by the coils 61 using an iron yoke 62. The MRI apparatus 60 includes gradient magnetic field coils and a high-frequency transmission / reception system (not shown) for generating magnetic resonance and collecting the resulting signals. The MRI apparatus 60 also includes a processing unit 63 (see FIG. 2) that controls the energization of the gradient magnetic field coil, generates an MRI image from the detected values ​​of the high frequency transmission / reception system, and outputs the image to the control unit 7 .

[0036] The pair of coils 61 have an annular shape centered on a central axis CL. The pair of coils 61 are spaced apart from each other in the direction of extension of the central axis CL, sandwiching the irradiation unit 2. As a result, the magnetic field generated by the MRI device 60 is parallel to the direction of extension of the central axis CL, i.e., perpendicular to the base axis AX of the particle beam B. At this time, the central axis CL of the coils 61 extends in a direction perpendicular to the base axis AX of the particle beam B irradiated from the irradiation unit 2. As a result, the patient 15 is placed on the treatment table 6 so that the tumor 14 (see FIG. 2) is within the uniform magnetic field generated by the coils 61 of the MRI device 60. In addition, an MRI image of the area around the tumor 14 is taken.

[0037] The yoke 62 of the MRI apparatus 60 includes a shield member 66 and a return yoke portion 67. The shield member 66 is a cylindrical member centered on the central axis CL. An opening 68 is formed in the shield member 66 at a position radially opposite the irradiation unit 2. The opening 68 allows the particle beam B irradiated from the irradiation unit 2 to pass through and guide it into the shield member 66. The return yoke portion 67 is a member that extends in a direction perpendicular to the central axis CL inside the shield member 66 at the rear side of the rotating gantry 17 and is connected to the inner circumferential surface of the shield member 66. The return yoke portion 67 and the shield member 66 form a path for magnetic flux, i.e., a magnetic circuit. The shield member 66 is configured as a structural member of the rotating gantry 17. The shield member 66 is configured as a cylindrical rotating shaft member of the rotating gantry 17. The shield member 66 rotates about the central axis CL. The shield member 66 is configured in a circular shape so as to completely surround the treatment table 6 and the MRI device 60 when viewed from the Y-axis direction (see FIG. 5).

[0038] The particle beam therapy system 1 according to this embodiment includes a treatment unit 70 , a treatment table 6 , a moving mechanism 75 , and a position adjustment unit 80 .

[0039] The treatment unit 70 is a mechanism for treating the patient 15. The treatment unit 70 is composed of the above-mentioned irradiation unit 2, rotating gantry 17, and MRI device 60. The treatment unit 70 has a treatment position 71, which is a position where treatment of the patient 15 is performed. The treatment position 71 is set in the space on the inner periphery side of the rotating gantry 17 and the MRI device 60. An isocenter CP1 (first reference point) of the irradiation unit 2 is set at the treatment position 71 of the treatment unit 70. The isocenter CP1 is the central point in the irradiation of the particle beam by the irradiation unit 2. The isocenter CP1 is set at the intersection of the central axis CL of the rotating gantry 17 and the base axis AX of the irradiation unit 2. Therefore, regardless of the rotation angle of the rotating gantry 17, the base axis AX passes through the isocenter CP1.

[0040] The treatment table 6 is a member on which the patient 15 is placed. When the treatment unit 70 treats the patient 15, the treatment table 6 is placed at a treatment position 71 with the patient 15 placed on its upper surface (see FIG. 1 ). That is, during treatment, the treatment table 6 is placed within the narrow internal space of the MRI device 60. The treatment table 6 is a plate-shaped member having a width that allows it to be placed within the narrow internal space of the MRI device 60 and having its longitudinal direction in the Y-axis direction. The inner diameter of the MRI device 60 is not particularly limited, but is approximately φ600 mm to φ700 mm, which makes it difficult to provide adjustment space for moving the treatment table 6 up and down and left and right, and to place an X-ray imager, camera, etc.

[0041] The moving mechanism 75 is a mechanism for moving the treatment couch 6. The moving mechanism 75 moves the treatment couch 6 between a treatment position 71 inside the MRI apparatus 60 and an adjustment position 81 outside the MRI apparatus 60. In FIG. 4 , the treatment couch 6 positioned at the treatment position 71 is shown by a virtual line, and the treatment couch 6 positioned at the adjustment position 81 is shown by a solid line. The adjustment position 81 is a position where the position adjustment unit 80 adjusts the position of the patient 15 before treatment. The adjustment position 81 is set to a position in front of the entrance opening of the MRI apparatus 60. The moving mechanism 75 moves the treatment couch 6 back and forth in the Y-axis direction between the treatment position 71 and the adjustment position 81. The moving mechanism 75 may move the treatment couch 6 back and forth at a predetermined reference distance. The height of the treatment couch 6 at the treatment position 71 and the height of the treatment couch 6 at the adjustment position 81 may be the same. The configuration of the moving mechanism 75 is not particularly limited, but may include a mechanism for transferring the treatment table 6 between a support provided at the adjustment position 81 and a support provided within the MRI device 60 (not shown).

[0042] The position adjustment unit 80 adjusts the position of the patient 15 on the treatment couch 6. The position adjustment unit 80 adjusts the position of the patient 15 at the adjustment position 81 before the treatment couch 6 moves to the treatment position 71. The position adjustment unit 80 adjusts the position of the patient 15 relative to an arbitrary reference position. In this embodiment, the position adjustment unit 80 includes a camera 82 that optically acquires images and an X-ray imager 83 that captures images using X-rays. However, the position adjustment unit 80 may include either the camera 82 or the X-ray imager 83. The position adjustment unit 80 detects the position of the patient 15 on the treatment couch 6 using the camera 82 and the X-ray imager 83, and enables adjustment of the position of the patient 15 based on the detection results. The position adjustment unit 80 also includes an output unit 96. The output unit 96 is a device that outputs various information, and may be, for example, a monitor. The output unit 96 outputs the detection results of the camera 82 and the X-ray imager 83. The operator may adjust the position of the patient 15 based on the detection result output to the output unit 96 .

[0043] In the position adjustment by the position adjustment unit 80, a pre-isocenter CP2 (second reference point) is set as a reference position at a position different from the isocenter CP1. The pre-isocenter CP2 is a reference point that is arbitrarily set relative to the space of the adjustment position 81. The position of the pre-isocenter CP2 is not particularly limited and may be set at any fixed position. Note that the reference position used as a reference in the position adjustment by the position adjustment unit 80 is not limited to the pre-isocenter CP2 and is not particularly limited as long as it is a position that can be used as a reference for position adjustment. For example, a mark provided on the treatment table 6 or any part such as an edge or corner of the treatment table 6 may be used as the reference position.

[0044] In the example shown in FIG. 4 , the pre-isocenter CP2 is set at an arbitrary position in the Y-axis direction above the treatment couch 6. The pre-isocenter CP2 may be set on the reference axis SL1, which is the center of imaging by the camera 82. The pre-isocenter CP2 may also be set on the reference axis SL2 of X-ray irradiation by the X-ray imager 83. For example, when the pre-isocenter CP2 is set in advance, the pre-isocenter CP2 is identified using a mark (such as a marker) provided on the equipment, and the position of the camera 82 is adjusted so that the pre-isocenter CP2 is captured at the center of the image captured by the camera 82. Once the camera 82 has been aligned with the pre-isocenter CP2, the camera 82 is kept stationary. Alternatively, when the camera 82 is moved, the pre-isocenter CP2 is moved around the pre-isocenter CP2 as the center of rotation so that the pre-isocenter CP2 is located at the center of the image.

[0045] A reference image prepared in advance may be used when performing position adjustment using the position adjustment unit 80. By outputting the reference image from the output unit 96, the operator can adjust the position of the patient 15 by comparing the reference image output to the output unit 96 with the actual position of the patient 15. The reference image indicates at least the position of the pre-isocenter CP2. The reference image also indicates the target positional relationship between the pre-isocenter CP2 and the patient 15. Such a reference image is prepared in advance prior to position adjustment. To create the reference image, an image including the pre-isocenter CP2 is acquired in advance using an image acquisition device for the reference image. Note that the camera 82 may be used as the image acquisition device for the reference image. The reference image is reconstructed by the treatment planning device 90 in accordance with the positional relationship between the image acquisition device and the pre-isocenter CP2. As a result, the treatment planning device 90 already has the reference image. The reference image is output to the output unit 96 when the position adjustment is performed by the position adjustment unit 80.

[0046] After the position adjustment by the position adjustment unit 80 is completed, the treatment couch 6 moves to the treatment position 71. After the position adjustment is completed, the treatment couch 6 moves to the treatment position 71 within the MRI device 60. After the treatment couch 6 moves to the treatment position 71, the patient 15 is positioned relative to the isocenter CP1 of the irradiation unit 2. This positioning may be performed based on the measurement results of the MRI device 60. The treatment planning device 90 prepares in advance information on how to position the tumor 14 of the patient 15 relative to the isocenter CP1. Therefore, if there is a discrepancy between the position of the tumor 14 obtained by the measurement results of the MRI device 60 and the position in the treatment plan, this information may be output to, for example, the output unit 96. This allows the operator to fine-tune the position of the patient 15 within the MRI device 60 to position the patient 15. Note that the position adjustment by the position adjustment unit 80 may be performed with accuracy within the range that can be achieved by positioning at the treatment position 71. For example, the position adjustment may be performed by the position adjustment unit 80 so that the amount of correction at the treatment position 71 is 10 mm or less.

[0047] Next, the operation and effects of the radiotherapy apparatus 100 according to this embodiment will be described.

[0048] The radiation therapy device 100 includes a treatment unit 70 having a treatment position 71 where treatment of the patient 15 is performed, and a treatment couch 6 on which the patient 15 is placed. Therefore, treatment can be performed in the treatment unit 70 by moving the treatment couch 6 to the treatment position 71 with the patient 15 placed on it. In response to this, the position adjustment unit 80 adjusts the position of the patient 15 relative to a reference position before the treatment couch 6 moves to the treatment position 71. Furthermore, the treatment couch 6 moves to the treatment position 71 after completing the position adjustment. This allows the position adjustment unit 80 to adjust the position of the patient 15 before the patient 15 is placed at the treatment position 71. This prevents the patient 15 from shifting position at the treatment position 71, eliminates the need to recalculate the treatment plan at the treatment position 71, and enables rapid treatment. As a result, the throughput of radiation therapy can be improved.

[0049] The treatment unit 70 includes an irradiation unit 2 that irradiates the patient 15 with particle beams B, a rotating gantry 17 that supports the irradiation unit 2 so that it can rotate around the patient 15, and an MRI device 60 that is attached to the rotating gantry 17 and acquires images of the patient 15 using a magnetic field. After position adjustment is complete, the treatment table 6 may be moved to a treatment position 71 within the MRI device 60. The inside of the MRI device 60 is small, and the range of on-site position adjustment of the patient 15 is limited. Therefore, the effect of performing position adjustment in advance using the position adjustment unit 80 becomes more pronounced.

[0050] After the treatment table 6 has moved to the treatment position, the patient 15 may be positioned relative to the isocenter CP1 of the irradiation unit 2. The position adjustment unit 80 roughly adjusts the position of the patient 15, and then the patient 15 is positioned relative to the isocenter CP1 at the treatment position 71, thereby improving the accuracy of the treatment.

[0051] Positioning may be performed based on the measurement results of the MRI device 60. This allows the patient 15 to be positioned at the treatment position without providing any additional measuring device or the like.

[0052] An isocenter CP1 serving as a reference for treatment is set at the treatment position 71, and a pre-isocenter CP2 serving as a reference position may be set at a position different from the isocenter CP1 during position adjustment. Setting the pre-isocenter CP2 to facilitate position adjustment makes it possible to easily perform position adjustment using the position adjustment unit 80.

[0053] The radiation therapy device 100 further includes a treatment planning device 90 that creates a treatment plan for the radiation therapy device 100. The treatment planning device 90 has a reference image indicating at least the position of the pre-isocenter CP2, and the reference image may be used in the position adjustment by the position adjustment unit 80. This allows the position adjustment by the position adjustment unit 80 to be easily performed based on the reference image that takes the treatment plan into consideration.

[0054] The present disclosure is not limited to the above-described embodiments.

[0055] In the above-described embodiment, a rotating gantry that rotates 360° has been exemplified, but a rotating gantry that rotates at a particularly limited rotation angle smaller than 360° may also be used. For example, a rotating gantry with a rotation angle of 180° or 270° may be used. In other words, the rotating gantry may be any gantry that can rotatably support the irradiation unit around the irradiated object, and there is no particular limitation on the range of rotation around the irradiated object.

[0056] Although a cyclotron is shown as an example of an accelerator in FIG. 1, the configuration of the present disclosure may also be adopted for various accelerators, such as a synchrocyclotron or a linear accelerator (linac).

[0057] Furthermore, the adjustment position 81 where the position adjustment is performed is not limited to the position shown in FIG. 4, and may be changed as appropriate depending on the configuration of the facility or treatment department.

[0058] 1...particle beam therapy device, 2...irradiation unit, 6...treatment table (mounting unit), 14...tumor (irradiated object), 15...patient (irradiated object), 17...rotating gantry, 60...MRI device (magnetic resonance imaging unit), 70...treatment unit, 71...treatment position, 80...position adjustment unit, 100...radiation therapy device, CP1...isocenter (first reference point), CP2...pre-isocenter (second reference point).

Claims

1. A radiation therapy apparatus for treating an irradiated object by radiation, comprising: a treatment unit having a treatment position which is a position for treating the irradiated object; a placement unit for placing the irradiated object; and a position adjustment unit for adjusting the position of the irradiated object at the placement unit, wherein the position adjustment unit performs position adjustment for adjusting the position of the irradiated object with respect to a reference position before the placement unit moves to the treatment position, and the placement unit moves to the treatment position after the position adjustment is completed.

2. The treatment unit includes: an irradiation unit for irradiating the irradiated object with a particle beam; a rotating gantry for rotatably supporting the irradiation unit around the irradiated object; and a magnetic resonance imaging unit provided on the rotating gantry for acquiring an image of the irradiated object by a magnetic field. The radiation therapy apparatus according to claim 1, wherein the placement unit moves to the treatment position within the magnetic resonance imaging unit after the position adjustment is completed.

3. The radiation therapy apparatus according to claim 2, wherein positioning of the irradiated object with respect to the isocenter of the irradiation unit is performed after the placement unit moves to the treatment position.

4. The radiation therapy apparatus according to claim 3, wherein the positioning is performed based on the measurement result of the magnetic resonance imaging unit.

5. A first reference point serving as a reference for treatment is set at the treatment position, and a second reference point serving as the reference position is set at a position different from the first reference point in the position adjustment. The radiation therapy apparatus according to claim 1.

6. The radiation therapy apparatus further includes a treatment planning apparatus for performing a treatment plan in the radiation therapy apparatus. The treatment planning apparatus has a reference image showing at least the position of the second reference point, and the reference image is used in the position adjustment by the position adjustment unit. The radiation therapy apparatus according to claim 5.

Images