Rotary gantry, and particle beam therapy system using the same

Abstract

To provide a rotary gantry that can reduce a margin in a depth direction in a shorter time than before, and a particle beam therapy system using the same.SOLUTION: A rotary gantry comprises: one or more port switching electromagnets 3 provided between an emitting point and an irradiation object; a first irradiation port 11 and a second irradiation port 12 for applying beams to the irradiation object from at least two or more directions branched by the port switching electromagnets 3; and measuring instruments 21a and 21b for measuring the energy of the beams passed through the first irradiation port 11 and the second irradiation port 12.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a rotating gantry having irradiation lines with two or more ports, and a particle beam therapy system using the same. [Background technology]

[0002] Patent Document 1 describes a particle beam therapy system capable of irradiating proton beams and helium beams as charged particle beams, and including a residual range measurement device that measures the energy of the proton beam that has passed through a patient, and a particle beam CT image generation device that determines the stopping power ratio distribution for the proton beam of the patient measured by the residual range measurement device, and calculates the stopping power ratio distribution for the helium beam based on the determined stopping power ratio distribution. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2020-146334 A Summary of the Invention [Problem to be solved by the invention]

[0004] When performing particle beam therapy, a treatment plan is made in advance using fluoroscopic images obtained by X-rays, CT scans, or the like in order to reduce the amount of radiation irradiated onto normal tissue and concentrate the dose on the affected area (see, for example, Patent Document 1).

[0005] However, when the irradiation depth (beam energy) is determined based on images obtained from X-ray fluoroscopy or CT images, the method of energy deposition differs significantly between the X-rays used to generate the images and the ions used in therapy.

[0006] For this reason, in the past, treatment plans were made with a margin in the depth direction, which meant that instead of ensuring that the cancerous area was irradiated, the beam would also irradiate some normal tissue.

[0007] Radiation from multiple directions is an effective way to reduce the amount of radiation given to normal tissue; however, when the lesion is close to tissue that is sensitive to radiation (such as the intestine), treatment can be difficult, and further reduction in the margin in the depth direction has been anticipated.

[0008] The above-mentioned Patent Document 1 describes that a transmission image is obtained by using a particle beam having a relatively similar mass. However, in Patent Document 1, the same irradiation port is used for irradiation for obtaining a transmission image and irradiation for treatment, and the present inventors have found through their study that there is room for obtaining a transmission image and performing treatment in a shorter time.

[0009] The present invention provides a rotating gantry that can reduce a margin in the depth direction in a shorter time than in the past, and a particle beam therapy system using the same. [Means for solving the problem]

[0010] The present invention includes multiple means for solving the above-mentioned problems. One example of the present invention is a rotating gantry that transports a beam extracted from an accelerator from an extraction point toward an irradiation target, and includes one or more beam branching electromagnets provided between the extraction point and the irradiation target, a beam path that irradiates the irradiation target with the beam from at least two directions branched by the beam branching electromagnets, and a beam measuring instrument that measures the energy of the beam that has passed through the beam path. Effect of the Invention

[0011] According to the present invention, it is possible to reduce the margin in the depth direction in a short time compared to the conventional art. Problems, configurations and effects other than those described above will become apparent from the following description of the embodiments. [Brief description of the drawings]

[0012] [Figure 1] FIG. 2 is a diagram showing an example of the configuration of a rotating gantry having two ports according to the first embodiment. [Diagram 2]FIG. 4 is a diagram showing another example of the configuration of the rotating gantry having two ports according to the first embodiment. [Diagram 3] FIG. 11 is a diagram showing an example of the configuration of a rotating gantry having two ports according to a second embodiment. [Figure 4] FIG. 11 is a diagram showing another example of the configuration of the rotating gantry having two ports according to the second embodiment. [Diagram 5] FIG. 11 is a diagram showing an example of the configuration of a rotating gantry having three ports according to a third embodiment. [Figure 6] FIG. 13 is a diagram illustrating an example of the configuration of a particle beam therapy system according to a fourth embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0013] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a rotating gantry according to the present invention and a particle beam therapy system using the rotating gantry will be described with reference to the drawings.

[0014] It should be noted that the following are merely examples, and are not intended to limit the contents of the invention to the specific embodiments described below. The invention itself can be modified into various forms other than the following examples.

[0015] In addition, in the drawings used in this specification, the same or corresponding components are denoted by the same or similar reference numerals, and repeated description of these components may be omitted.

[0016] <Example 1> A rotating gantry according to a first embodiment of the present invention will be described with reference to Fig. 1 and Fig. 2. Fig. 1 is a diagram showing an example of the configuration of a rotating gantry having two ports according to the first embodiment, and Fig. 2 is a diagram showing another example of the configuration of a rotating gantry having two ports.

[0017] The rotating gantry 10 having two ports shown in FIG. 1 is a device that transports the beam emitted from the accelerator 100 from the exit point of the accelerator 100 toward an irradiation target, and has a bending electromagnet 2, a port switching electromagnet 3, a scanning electromagnet 4, beam scatterers 5a and 5b, a first irradiation port 11, a second irradiation port 12, measuring instruments 21a and 21b, etc.

[0018] The rotating gantry 10 rotates around the patient 301 about a rotation axis 1. The rotation angle of the rotating gantry 10 is preferably 360 degrees, but is not limited to this and can be, for example, 180 degrees. Since the rotating gantry 10 rotates around the patient 301 in this way, it is possible to irradiate the affected area from any direction and to avoid the effects of radiation on normal organs that are sensitive to radiation, and therefore it is often used in recent particle beam therapy.

[0019] The beam incident on the rotating gantry 10 has its trajectory changed by the bending electromagnet 2 and is guided to the patient 301. The bending electromagnet 2 in Fig. 1 shows a case in which a combined electromagnet is used that combines the functions of an electromagnet that deflects (bends) the ion beam and a quadrupole electromagnet that suppresses beam divergence, but the bending electromagnet and quadrupole electromagnet may be installed separately.

[0020] The port switching electromagnet 3 is an electromagnet provided between the emission point and the irradiation target, and branches the beam destination based on an instruction to irradiate the irradiation target with the beam from either the first irradiation port 11 or the second irradiation port 12.

[0021] When performing treatment with an ion beam, the port switching electromagnet 3 is not excited, and the ion beam passes through the bending electromagnets 2a, 2b, and 2c and the first irradiation port 11 and is irradiated onto the affected area of ​​the patient 301. At this time, the trajectory of the transported ion beam is controlled by the scanning electromagnet 4 in the rotating gantry 10 in accordance with the shape of the affected area.

[0022] The bending electromagnets 2a, 2b, and 2c are shown divided in order to clearly show the passage path of the ion beam, and the arrangement of the electromagnets is not limited to that shown in FIG.

[0023] Also, as in a rotating gantry 10A shown in FIG. 2, the scanning electromagnet 4 may be disposed within the first irradiation port 11.

[0024] The beam scatterers 5a and 5b are structures for scattering the beam to expand the beam size so as to increase the range in which a target image can be obtained.

[0025] Since it is desirable for these beam scatterers 5a, 5b to be expelled from the ion beam passing area during treatment, they can be inserted / ejected onto the beam axis within the first irradiation port 11 and the second irradiation port 12 depending on the time of fluoroscopic image capture and treatment, and are equipped with a driving mechanism (omitted for convenience of illustration).

[0026] The beam scatterers 5a and 5b are not particularly limited and may be dedicated to the first irradiation port 11 and the second irradiation port 12, or may be shared by both. The thickness and other properties of the beam scatterers can be appropriately changed depending on the target size.

[0027] The first irradiation port 11 is a port used when irradiating a beam from direction A in Figure 1 to an irradiation target located at the isocenter 50, and the second irradiation port 12 is a port used when irradiating a beam from direction B in Figure 1 to an irradiation target located at the isocenter 50.

[0028] The first irradiation port 11 and the second irradiation port 12 make it possible to irradiate the irradiation target with beams from at least two directions branched by the port switching electromagnet 3 .

[0029] The measuring instrument 21 a is a measuring instrument that measures the energy of the beam that has passed through the first irradiation port 11 , and the measuring instrument 21 b is a measuring instrument that measures the energy of the beam that has passed through the second irradiation port 12 .

[0030] In this embodiment, as shown in Figure 1 or Figure 2, there are an equal number of first irradiation ports 11, second irradiation ports 12 and measuring instruments 21a, 21b, and the measuring instruments 21a, 21b are configured to move according to the rotation angle of the rotating gantry 10.

[0031] It is not necessary that the number of the first irradiation ports 11, the second irradiation ports 12, and the measuring instruments 21a, 21b are the same. It is also possible to provide one measuring instrument that is movable according to the port to be used.

[0032] When obtaining a fluoroscopic image using an ion beam, the ion beam is scattered (the beam size is expanded) so as to cover the range for obtaining the fluoroscopic image by inserting the beam scatterer 5a into the beam passing area in the first irradiation port 11, or the beam scatterer 5b into the beam passing area in the second irradiation port 12.

[0033] When the port switching electromagnet 3 is not excited, a fluoroscopic image from direction A via the first irradiation port 11 can be obtained by the measuring instrument 21a, and when the port switching electromagnet 3 is excited, a fluoroscopic image from direction B via the second irradiation port 12 can be obtained by the measuring instrument 21b.

[0034] The penetration depth of the ions (ion energy) used differs between when performing treatment with an ion beam and when taking a fluoroscopic image. The energy of the treatment beam is set so that the beam stops at the affected area inside the patient 301, whereas the energy of the fluoroscopic image beam is set so that it passes through the body of the patient 301 and reaches the measuring instruments 21a and 21b (higher energy than the treatment beam).

[0035] The types of ions to be irradiated may be the same or different. For example, in the case of a proton beam therapy device, proton beams are used for both. In what are generally called heavy particle beam therapy devices, such as helium or carbon beam therapy, helium or carbon ions are used for treatment, and lighter ions, such as protons or helium, are used for fluoroscopic imaging, making it possible to generate a high-energy beam that penetrates the patient 301 without increasing the size of the accelerator. Of course, the same ions may be used for treatment and fluoroscopic imaging in heavy particle beam therapy devices as well.

[0036] Next, the effects of this embodiment will be described.

[0037] The rotating gantry 10, 10A that transports the beam extracted from the accelerator 100 of the above-mentioned embodiment 1 of the present invention from the extraction point to the irradiation target is equipped with one or more port switching electromagnets 3 provided between the extraction point and the irradiation target, a first irradiation port 11 and a second irradiation port 12 that irradiate the beam to the irradiation target from at least two directions branched by the port switching electromagnets 3, and measuring instruments 21a and 21b that measure the energy of the beam that has passed through the first irradiation port 11 and the second irradiation port 12.

[0038] This allows fluoroscopic images to be created from two or more directions using the same or equivalent ions as those used to treat the affected area, and treatment plans can be formulated and corrected based on these images, making it possible to formulate treatment plans with smaller depth margins compared to treatment plans using conventional X-ray fluoroscopic images. This makes it possible to reduce unnecessary radiation doses to normal tissues and to treat areas that were previously difficult to treat with particle beam therapy. It also makes it possible to simplify treatment plans, such as by reducing the number of radiation directions. This also has the secondary effect of shortening treatment times.

[0039] In addition, due to the presence of the port switching electromagnet 3 in the rotating gantries 10, 10A, the irradiation direction can be changed by turning the port switching electromagnet 3 on and off, compared to rotating the irradiation port. This enables high-speed switching of the irradiation port and makes it possible to obtain images during irradiation with higher accuracy (especially in the depth direction) in a very short time, thereby shortening the treatment time and making the technology more suitable for online adaptive treatment.

[0040] In addition, the system is provided with the same number of first irradiation ports 11, second irradiation ports 12 and measuring instruments 21a, 21b, and the measuring instruments 21a, 21b move according to the rotation angle of the rotating gantries 10, 10A, eliminating the need for time to move the measuring instruments and enabling faster switching of the irradiation direction.

[0041] Furthermore, the device is further provided with beam scatterers 5a, 5b which scatter the beam to expand the beam size, and the beam scatterers 5a, 5b can be inserted / ejected onto / from the beam axis in the first irradiation port 11 and the second irradiation port 12 depending on the time of fluoroscopy image capture and treatment, making it easier to switch to the mode when capturing a fluoroscopy image, and achieving even faster switching of the irradiation direction and irradiation mode.

[0042] Furthermore, since the beam scatterers 5a and 5b are disposed downstream of the port switching electromagnet 3, it is possible to avoid an increase in the size of the electromagnet on the downstream side, and therefore it is possible to reduce the size of the rotating cantry.

[0043] <Example 2> A rotating gantry according to a second embodiment of the present invention will be described with reference to Fig. 3 and Fig. 4. Fig. 3 is a diagram showing an example of the configuration of a rotating gantry having two ports according to the second embodiment, and Fig. 4 is a diagram showing another example of the configuration of a rotating gantry having two ports.

[0044] The rotating gantries 10B and 10C having two ports of this embodiment shown in FIG. 3 or FIG. 4 have the same basic principle as the rotating gantries 10 and 10A of the first embodiment, but the first irradiation port 11 and the second irradiation port 12 are configured to be capable of irradiating a therapeutic ion beam from at least two or more directions, and are configured to transport a therapeutic ion beam to the second irradiation port 12 as well when the port switching electromagnet 3 is excited.

[0045] The difference from the first embodiment is that the port switching electromagnet 3 is controlled with an optimum excitation amount for the fluoroscopic image capturing beam and the treatment beam.

[0046] Examples of irradiation of therapeutic beams from two different planes are shown in Figures 3 and 4. Figure 3 shows an example in which scanning magnets 4 and 4b are placed at each irradiation port, while Figure 4 shows an example in which these functions are integrated and the scanning magnet 4 is placed upstream of the port switching magnet 3 where the transport system branches off.

[0047] The other configurations and operations are substantially the same as those of the rotating gantry of the first embodiment described above, and the details are omitted here.

[0048] The rotating gantry according to the second embodiment of the present invention also provides substantially the same effects as those of the rotating gantry according to the first embodiment described above.

[0049] Furthermore, the first irradiation port 11 and the second irradiation port 12 can irradiate the therapeutic ion beam from at least two directions, and thus, in addition to fluoroscopic imaging using ion beams from two directions, it is possible to irradiate the therapeutic ion beam in two different planes (non-coplanar irradiation). That is, in the case of a conventional one-port rotating gantry, it was necessary to change the orientation of the patient 301 in order to irradiate the therapeutic ion beam in two different planes, but in this embodiment, it is not necessary to move the patient 301, and it is possible to eliminate as much as possible factors of error such as changes in the shape of the affected area and changes in the path to the affected area due to changes in the posture of the patient 301. That is, it is possible to realize more accurate radiation irradiation and to finish the irradiation in a shorter time.

[0050] <Example 3> A rotating gantry according to a third embodiment of the present invention will be described with reference to Fig. 5. Fig. 5 is a diagram showing an example of the configuration of a rotating gantry having three ports according to the third embodiment.

[0051] The rotating gantry 10D of this embodiment shown in FIG. 5 is equipped with a first irradiation port 11 and a second irradiation port 12 that irradiate the irradiation target with beams from at least two directions branched by the port switching electromagnets 3 and 3A, as well as a third irradiation port 13 that irradiates a fluoroscopic image capturing beam and / or a treatment beam from direction C.

[0052] In this configuration, in addition to the measuring instruments 21a and 21b, a measuring instrument 21c that measures the energy of the beam that has passed through the third irradiation port 13 and a beam scatterer 5c that scatters the beam to expand the beam size are further provided.

[0053] In this embodiment, when a fluoroscopic imaging beam and / or a treatment beam is irradiated from the C direction, the port switching electromagnet 3A is excited to pass through the third irradiation port 13. When a fluoroscopic imaging beam and / or a treatment beam is irradiated from the A direction, the port switching electromagnet 3A is not excited, and the port switching electromagnet 3 is not excited or is excited with an optimal excitation amount to pass through the first irradiation port 11. When a fluoroscopic imaging beam and / or a treatment beam is irradiated from the B direction, the port switching electromagnet 3A is not excited, and the port switching electromagnet 3 is excited with an optimal excitation amount to pass through the second irradiation port 12.

[0054] Other configurations and operations are substantially the same as those of the rotating gantries 10 and 10A of the first embodiment or the rotating gantries 10B and 10C of the second embodiment, and detailed description thereof will be omitted.

[0055] The rotating gantry according to the third embodiment of the present invention also provides substantially the same effects as those of the rotating gantry according to the first embodiment described above.

[0056] In addition, when there are three or more irradiation ports, it is sufficient to provide only one port switching electromagnet, but it is preferable to branch in only two directions, and it is preferable to provide one port switching electromagnet less the number of irradiation ports.

[0057] <Example 4> A particle beam therapy system according to a fourth embodiment of the present invention will be described with reference to Fig. 6. Fig. 6 is a diagram showing an example of the configuration of the particle beam therapy system according to the fourth embodiment.

[0058] This embodiment is a particle beam therapy system 500 including an accelerator 100 that generates a beam and any one of the rotating gantry 10, 10A, 10B, 10C, and 10D having two ports described in any one of the above-mentioned embodiments 1 to 3.

[0059] This particle beam therapy system 500 is composed of an accelerator 100, a beam transport and irradiation system 200 equipped with any one of the rotating gantries 10, 10A, 10B, 10C, and 10D, and a control device 400 that controls the operations of these systems. In the particle beam therapy system 500, the type of ions in the beam irradiated from at least two or more directions can be changed, and preferably the energy of the ions irradiated from at least two or more directions can be changed.

[0060] The control device 400 has an irradiation control system 401 that controls the operation of each device in the transport system (other than the first irradiation port 11, the second irradiation port 12, and the third irradiation port 13) of the accelerator 100 and the beam transport and irradiation system 200, and an accelerator and beam transport control system 402 that controls the operation of each device in the irradiation system (the first irradiation port 11, the second irradiation port 12, and the third irradiation port 13) of the beam transport and irradiation system 200.

[0061] According to the treatment plan (including fluoroscopic imaging), the ions to be accelerated are switched as necessary using an ion source switching signal 411, and the operating conditions of the accelerator 100 and the beam transport / irradiation system 200 are changed using an accelerator equipment control signal 412 and a transport system electromagnet control signal 413.

[0062] Moreover, by switching the port for capturing a treatment or fluoroscopic image using a port switching electromagnet control signal 414, it is possible to change the irradiation direction of the beam.

[0063] If necessary, during fluoroscopic imaging, beam scatterers 5a, 5b, and 5c are inserted by a beam scatterer insertion signal 415 to expand the beam size according to the size of the target to be imaged. During treatment, the beam scatterers 5a, 5b, and 5c are removed from the beam passing region by a beam scatterer ejection signal 416.

[0064] The configuration and operation of the rotating gantry are substantially the same as those of any of the rotating gantries of the first to third embodiments described above, and detailed description thereof will be omitted.

[0065] In the particle beam therapy system according to the fourth embodiment of the present invention, substantially the same effects as those of the particle beam therapy system according to the first embodiment described above can be obtained.

[0066] In addition, since the type of ions in the beam irradiated from at least two or more directions can be changed, and the energy of the ions irradiated from at least two or more directions can be changed, it is possible to irradiate the same particles for both CT and treatment, thereby enabling more flexible treatment.

[0067] <Other> The present invention is not limited to the above-mentioned embodiment, but includes various modified examples. The above-mentioned embodiment has been described in detail to explain the present invention in an easily understandable manner, and the present invention is not necessarily limited to the embodiment having all of the described configurations.

[0068] It is also possible to replace a part of the configuration of one embodiment with the configuration of another embodiment, or to add the configuration of another embodiment to the configuration of one embodiment. It is also possible to add, delete, or replace part of the configuration of each embodiment with the configuration of another embodiment.

[0069] For example, the embodiment of the present invention may be in the following form.

[0070] (1) A rotating gantry that transports a beam extracted from an accelerator from an extraction point to an irradiation target, comprising one or more beam branching electromagnets provided between the extraction point and the irradiation target, a beam path that irradiates the irradiation target with the beam from at least two directions branched by the beam branching electromagnets, and a beam measuring instrument that measures the energy of the beam that has passed through the beam path.

[0071] (2) In the rotating gantry described in (1), the number of the beam paths and the number of the beam measuring instruments are the same, and the beam measuring instruments move according to the rotation angle of the rotating gantry.

[0072] (3) The rotating gantry according to (1) or (2) further comprises a scatterer that scatters the beam to expand the beam size, and the scatterer can be inserted / ejected onto the beam axis within the beam path depending on the time of fluoroscopic image capture or treatment.

[0073] (4) In the rotating gantry described in (3), the scatterer is disposed downstream of the beam-branching electromagnet.

[0074] (5) In the rotating gantry described in any one of (1) to (4), the beam path is capable of irradiating a therapeutic ion beam from at least two or more directions. [Explanation of symbols]

[0075] 1...Rotation axis 2a,2b,2c...Bending electromagnet 3,3A…Port switching magnet (electromagnet for beam branching) 4,4b…Scanning electromagnet 5a,5b,5c...Beam scatterer 10, 10A, 10B, 10C, 10D...Rotating gantry 11...First irradiation port (beam path) 12...Second irradiation port (beam path) 13...Third irradiation port (beam path) 21a, 21b, 21c...Measuring instruments (beam measuring instruments) 50…Isocenter 100...Accelerator 200…Beam transport and irradiation system 301...patient 400...Control device 401...Irradiation control system 402...Accelerator / Beam Transport Control System 411...Ion switching signal 412...Accelerator equipment control signal 413...Transportation system electromagnetic control signal 414...Port switching electromagnet control signal 415…Beam scatterer insertion signal 416…Beam scatterer ejection signal 500…Particle beam therapy system

Claims

1. A rotating gantry that transports a beam emitted from an accelerator from an emission point toward an irradiation target, one or more beam branching electromagnets provided between the emission point and the irradiation target; a beam path for irradiating the irradiation target with beams from at least two directions branched by the beam branching electromagnet; a beam measuring device for measuring the energy of the beam that has passed through the beam path. Rotating gantry.

2. 2. The rotating gantry of claim 1, The beam path and the beam measuring instrument are provided in equal numbers, The beam measuring device moves according to the rotation angle of the rotating gantry. Rotating gantry.

3. 2. The rotating gantry of claim 1, Further comprising a scatterer for scattering the beam to expand the beam size, The scatterer can be inserted / removed onto the beam axis in the beam path depending on the time of fluoroscopic image capture and treatment. Rotating gantry.

4. 4. The rotating gantry according to claim 3, The scatterer is disposed downstream of the beam-splitting electromagnet. Rotating gantry.

5. 2. The rotating gantry of claim 1, The beam path is capable of irradiating a therapeutic ion beam from at least two directions. Rotating gantry.

6. the accelerator for generating the beam; A rotating gantry according to any one of claims 1 to 5, The type of ions in the beam irradiated from at least two or more directions can be changed. Particle beam therapy system.

7. 7. The particle beam therapy system according to claim 6, The energy of the ions irradiated from at least two or more directions can be changed. Particle beam therapy system.

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