Particle beam irradiation system

Abstract

To make it possible to efficiently provide a particle beam irradiation system on a limited site of an urban area, etc. and contribute to a reduction in construction costs.SOLUTION: A particle beam irradiation system 1 comprises: a first building 21; a second building 22 different from the first building 21; an accelerator 4 provided in the first building 21, and for accelerating a charged particle beam B; beam transport lines 5 and 6 for guiding the charged particle beam B accelerated by the accelerator 4; and an irradiation device 51 provided in the second building 22, and for irradiating an irradiation object P with the charged particle beam B guided by the beam transport lines 5 and 6.SELECTED DRAWING: Figure 5

Description

[Technical field]

[0001] FIELD OF THE DISCLOSURE An embodiment of the present invention relates to a particle beam irradiation system. [Background technology]

[0002] Conventionally, there is a particle beam therapy facility equipped with an irradiation device such as a rotating gantry for radiation therapy. In order to install this particle beam therapy facility on a limited site such as an urban area, a technology is known in which a floor in a single building is divided into an upper floor and a lower floor, in which a particle accelerator is installed and an irradiation device is installed. However, if a large device such as an accelerator or a rotating gantry is installed on the upper floor away from the ground, which is the foundation, the building needs to be constructed firmly. Furthermore, the shape of the beam transport line connecting the upper and lower floors is complicated with many bends, and many bending electromagnets need to be installed. This increases the construction cost. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent No. 5437527 [Patent Document 2] JP 2019-180654 A [Patent Document 3] JP 2020-779 A [Patent Document 4] JP 2021-153759 A Summary of the Invention [Problem to be solved by the invention]

[0004] The problem to be solved by the present invention is to efficiently install a particle beam irradiation system in a limited area such as an urban area, and to contribute to reducing construction costs. [Means for solving the problem]

[0005] A particle beam irradiation system according to an embodiment of the present invention comprises a first building, a second building different from the first building, an accelerator provided in the first building for accelerating a charged particle beam, a beam transport line for guiding the charged particle beam accelerated by the accelerator, and an irradiation device provided in the second building for irradiating an irradiation target with the charged particle beam guided by the beam transport line. Effect of the Invention

[0006] According to the embodiment of the present invention, a particle beam irradiation system can be efficiently installed in a limited area such as an urban area, and can contribute to reducing construction costs. [Brief description of the drawings]

[0007] [Figure 1] FIG. 1 is a plan view showing a particle beam irradiation system according to a first embodiment. [Diagram 2] FIG. 1 is a side view showing a particle beam irradiation system according to a first embodiment. [Diagram 3] FIG. 13 is a side view showing a half gantry as an irradiation device of a modified example. [Figure 4] FIG. 11 is a side view showing a particle beam irradiation system according to a second embodiment. [Diagram 5] FIG. 11 is a side view showing a particle beam irradiation system according to a third embodiment. [Figure 6] FIG. 13 is a side view showing a slit-type irradiation device as an irradiation device of a third embodiment. [Figure 7] FIG. 13 is a front view showing a slit-type irradiation device as an irradiation device of a third embodiment. [Figure 8] FIG. 11 is a side view showing a beam transport line according to the third embodiment. [Figure 9] FIG. 1 is a side view showing a conventional beam transport line. [Figure 10] FIG. 13 is a side view showing a particle beam irradiation system according to a fourth embodiment. [Figure 11] FIG. 13 is a side view showing a particle beam irradiation system according to a fifth embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0008] (First embodiment) Hereinafter, embodiments of a particle beam irradiation system will be described in detail with reference to the drawings. First, a first embodiment will be described with reference to FIGS.

[0009] Reference numeral 1 in Fig. 1 denotes a particle beam irradiation system according to a first embodiment. This particle beam irradiation system 1 is a so-called particle beam cancer treatment device that performs treatment by irradiating a lesion tissue (cancer) of a patient P as an irradiation target with a charged particle beam such as carbon ions as therapeutic radiation.

[0010] Radiation therapy technology using the particle beam irradiation system 1 is also known as heavy particle beam cancer therapy technology. This technology uses carbon ions to pinpoint cancer lesions (affected areas), damaging the cancer lesions while minimizing damage to normal cells. Charged particle beams are defined as radiation heavier than electrons, and include proton beams and heavy particle beams. Of these, heavy particle beams are defined as those heavier than helium atoms.

[0011] In this embodiment, the charged particle beam uses carbon, but other configurations are also possible, such as a charged particle beam using helium, oxygen, or neon.

[0012] Cancer treatment using heavy ion beams has a higher ability to kill cancer lesions than conventional cancer treatment using X-rays, gamma rays, or proton beams, and has the characteristic that the radiation dose is weak on the surface of the patient P's body and peaks at the cancer lesion. Therefore, the number of irradiations and side effects can be reduced, and the treatment period can be shortened.

[0013] For example, when a charged particle beam passes through the body of the patient P, it loses kinetic energy and decreases in speed, and encounters resistance that is approximately inversely proportional to the square of the speed, and suddenly stops when it has decreased to a certain speed. The stopping point of the charged particle beam is called the Bragg peak, and high energy is released. The particle beam irradiation system 1 can annihilate only the diseased tissue while suppressing damage to normal tissue by aligning this Bragg peak with the position of the diseased tissue (affected area) of the patient P.

[0014] The particle beam irradiation system 1 includes an ion generator 2, a linear accelerator 3, a circular accelerator 4, a main transport line 5, a sub-transport line 6, and a rotating gantry 7. The main transport line 5 and the sub-transport line 6 form a beam transport line.

[0015] The ion generator 2 has an ion source of carbon ions, which are charged particles, and generates a charged particle beam by the carbon ions. The linear accelerator 3 is linear in plan view and accelerates the ions generated by the ion generator 2 to form a charged particle beam. The linear accelerator 3 then introduces this charged particle beam into the circular accelerator 4.

[0016] The circular accelerator 4 has a ring shape in a plan view, and further accelerates the charged particle beam. Here, the charged particle beam is accelerated to about 70% of the speed of light while orbiting the circular accelerator 4 about one million times. The charged particle beam accelerated by the circular accelerator 4 is then transported to the rotating gantry 7 by the main transport line 5 and the sub transport line 6. Inside this rotating gantry 7, a patient P to be irradiated with the charged particle beam is placed. Inside the rotating gantry 7, an isocenter C is set, which is the position where the charged particle beam is irradiated most intensively, and the affected area of ​​the patient P is placed at this isocenter C.

[0017] The ion generator 2, the linear accelerator 3, the circular accelerator 4, the main transport line 5, and the sub transport line 6 are provided with a vacuum duct 8 (beam pipe) that is evacuated and extends integrally with them. The charged particle beam travels inside this vacuum duct 8. This vacuum duct 8 forms a transport path that guides the charged particle beam from the ion generator 2 to the rotating gantry 7. In other words, the vacuum duct 8 is a sealed continuous space with a sufficient degree of vacuum to allow the charged particle beam to pass through.

[0018] The circular accelerator 4 includes a radio frequency accelerating cavity 9, a bending electromagnet 10, and a focusing electromagnet 11. The radio frequency accelerating cavity 9 accelerates the carbon ions by controlling the frequencies of a magnetic field and an accelerating electric field.

[0019] The main transportation line 5 includes a bending electromagnet 12 and a focusing electromagnet 13. The main transportation line 5 extends from the circular accelerator 4. A plurality of sub-transport lines 6 are connected to a linear portion of the main transportation line 5.

[0020] Each of the sub-transport lines 6 includes a bending electromagnet 14 and a focusing electromagnet 15. In this embodiment, two sub-transport lines 6 are connected to one main transportation line 5. Each of the sub-transport lines 6 extends to a rotating gantry 7.

[0021] In other words, the beam transport line consisting of the main transport line 5 and a plurality of sub-transport lines 6 guides the charged particle beam accelerated by the circular accelerator 4 to the rotating gantry 7 .

[0022] Although detailed illustration is omitted, the rotating gantry 7 is a cylindrical device. The rotating gantry 7 is arranged so that the axis of the cylinder faces the horizontal direction. The rotating gantry 7 can rotate around the horizontal axis over its entire circumference. The rotating gantry 7 serves as the irradiation device of the first embodiment.

[0023] End rings (not shown) are fixed to the front and rear edges of the rotating gantry 7. Rotational drive units (not shown) that rotatably support the end rings and include a drive motor are provided below these end rings. These rotational drive units are supported by the frame. The driving force of the rotational drive units is applied to the rotating gantry 7 via the end rings, causing the rotating gantry 7 to rotate around a horizontal axis.

[0024] The rotating gantry 7 also includes a bending electromagnet 16, a focusing electromagnet 17, and an irradiation nozzle 18. The irradiation nozzle 18, the bending electromagnet 16, and the focusing electromagnet 17 are supported by the rotating gantry 7 and are rotatable together with the rotating gantry 7.

[0025] The rotating gantry 7 is provided with a vacuum duct 8 continuing from the sub-transport line 6. The vacuum duct 8 is first led from an end of the rotating gantry 7 to the inside along its horizontal axis. The vacuum duct 8 then extends once outward beyond the outer circumferential surface of the rotating gantry 7, and then extends again inward of the rotating gantry 7. An irradiation nozzle 18 at which the tip of the vacuum duct 8 is located extends to a position close to the patient P.

[0026] In addition, a predetermined rotation mechanism (not shown) is provided in the vacuum duct 8 at a portion along the horizontal axis of the rotating gantry 7. The portion of the vacuum duct 8 outside this rotation mechanism is stationary, and the portion inside this rotation mechanism rotates together with the rotation of the rotating gantry 7.

[0027] The irradiation nozzle 18 is provided at the tip of the vacuum duct 8, and irradiates the charged particle beam guided by the bending electromagnet 16 and the focusing electromagnet 17 toward the patient P. The irradiation nozzle 18 is fixed to the inner peripheral surface of the rotating gantry 7. The charged particle beam is irradiated from the irradiation nozzle 18 in a direction perpendicular to the horizontal axis.

[0028] The patient P is placed at the position of the horizontal axis, and by rotating the rotating gantry 7, the irradiation nozzle 18 can be rotated around the stationary patient P. For example, the irradiation nozzle 18 can be rotated 180 degrees in one direction and then the other in the circumferential direction of the rotating gantry 7 around the patient P (horizontal axis), for a total of 360 degrees. Then, the charged particle beam can be irradiated from any direction around the patient P. In other words, the rotating gantry 7 is a device that can change the irradiation direction of the charged particle beam guided by the sub-transport line 6 to the patient P. Therefore, the charged particle beam can be accurately irradiated to the affected area from the optimal direction while reducing the burden on the patient P.

[0029] The irradiation nozzle 18 moves around the entire circumference of the isocenter C, where the patient P to be irradiated is located, at a position equidistant from the isocenter C, and is capable of changing the irradiation direction of the charged particle beam with respect to the isocenter C.

[0030] Although detailed illustration is omitted, the irradiation nozzle 18 includes devices such as a scanning electromagnet, a beam monitor, and an energy modulator. The scanning electromagnet adjusts the amount and direction of current flow to finely adjust the traveling direction of the charged particle beam emitted from the irradiation nozzle 18, and scans the charged particle beam in a relatively narrow range. The beam monitor monitors the charged particle beam and measures the dose, irradiation position, and flatness of the beam. The energy modulator adjusts the energy of the charged particle beam to adjust the depth at which the charged particle beam reaches the body of the patient P. The energy modulator is, for example, a range modulator, a scatterer, a ridge filter, a collimator, a bolus, an applicator, or a combination of these.

[0031] The aforementioned bending electromagnets 10, 12, 14, 16 and focusing electromagnets 11, 13, 15, 17 are electromagnets that generate a magnetic field that forms a transport path of the charged particle beam, and are arranged to surround the outer periphery of the vacuum duct 8. Here, the bending electromagnets 10, 12, 14, 16 change the traveling direction of the charged particle beam along the vacuum duct 8. Also, the focusing electromagnets 11, 13, 15, 17 control the convergence and divergence of the charged particle beam. The focusing electromagnets 11, 13, 15, 17 are composed of quadrupole electromagnets or sextupole electromagnets, etc.

[0032] The bending electromagnets 10, 12, 14, and 16 and the converging electromagnets 11, 13, 15, and 17 in this embodiment may be composed of superconducting magnets.

[0033] As shown in Fig. 1 and Fig. 2, the particle beam irradiation system 1 of the first embodiment includes a first building 21, a second building 22 different from the first building 21, and a connection unit 23 connecting the first and second buildings 21 and 22. The first building 21 and the second building 22 are multi-storey buildings. For example, each of the first building 21 and the second building 22 includes a first floor above ground with a floor surface F constructed at a position higher than the ground G, and a first basement floor with a floor surface F constructed at a position lower than the ground G. The floor surfaces F of the first basement floors of the first building 21 and the second building 22 are constructed to be at the same position.

[0034] An accelerator room 24 is formed on the first basement floor of the first building 21 in which devices such as the linear accelerator 3 and the circular accelerator 4 are installed. In addition, an irradiation room 25 is formed on the first basement floor of the second building 22 in which devices such as the rotating gantry 7 are installed.

[0035] 1 and 2 are simplified for ease of understanding, but the actual rotating gantry 7 is a large device. Therefore, compared with the accelerator room 24 in which the circular accelerator 4 and the like are installed, the irradiation room 25 in which the rotating gantry 7 is installed may have a lower floor F and a higher ceiling.

[0036] Furthermore, in the first building 21, there are also areas other than the accelerator room 24, such as an accelerator control room 26 in which staff who control the linear accelerator 3 and the circular accelerator 4 are located. In the second building 22, there are also areas other than the irradiation room 25, such as an irradiation control room 27 in which staff who control the rotating gantry 7 are located.

[0037] The first building 21 and the second building 22 are connected via a connection part 23 constructed underground. The main transportation line 5 extends from the accelerator room 24 to the irradiation room 25 via the connection part 23. Although not particularly shown, a passage for people to travel between the first building 21 and the second building 22 may be provided between the first building 21 and the second building 22 in addition to the connection part 23.

[0038] The inside of the first building 21 and the second building 22 is divided into a radiation controlled area where the accelerator room 24 and the irradiation room 25 are located, and the rest of the normal area. The radiation controlled area is an area that is set up to clearly demarcate areas with a certain level of radiation or more and to prevent people from entering the area unnecessarily in order to prevent people from being exposed to radiation unnecessarily. The construction of this radiation controlled area is determined by law. The connection part 23 is also part of the radiation controlled area.

[0039] The linear accelerator 3, circular accelerator 4, main transport line 5, sub transport line 6, and rotating gantry 7 are devices that emit radiation during operation, and are therefore located in a radiation controlled area. The radiation controlled area is separated by shielding walls that block radiation. On the other hand, the normal area is separated by normal walls that are not designed to block radiation.

[0040] In general, the thickness T of the shielding wall is 1 to 2 m or more. However, if a metal plate such as lead or iron is provided inside the shielding wall, the thickness T of the shielding wall may be less than 1 m. The shielding wall here includes the ceiling and floor of the radiation controlled area.

[0041] At the time of designing the particle beam irradiation system 1, the designer will provide a linear portion of the beam transport line at a position connecting the first building 21 and the second building 22. For example, as shown in FIG. 1, in the main transport line 5, the portion connecting the first building 21 and the second building 22 is linear. In other words, a portion of the main transport line 5 disposed at the connection portion 23 is linear. In this way, the radiation shielding wall provided around the main transport line 5 can be made thin, and construction costs can be reduced.

[0042] 2, the connection part 23 is provided underground. That is, the part of the main transportation line 5 that connects the first building 21 and the second building 22 is provided underground. In this way, radiation will not leak from the main transportation line 5 to the outside.

[0043] In the first embodiment, the first building 21 is constructed on one of two building sites 31, 32 adjacent to each other across a road site 30, and the second building 22 is constructed on the other. In this way, the particle beam irradiation system 1 can be constructed while maintaining the road on which people and vehicles pass. For example, the particle beam irradiation system 1 can be constructed in a place where land acquisition is limited, such as an urban area. The road site 30 referred to here includes sites used for sidewalks, roadways, railways (railroad tracks), and waterways (rivers, canals). Roads include outdoor roads, tunnels, and underground passages.

[0044] Next, a modified example will be described with reference to Fig. 3. In the above-described embodiment, the rotating gantry 7 is exemplified as the irradiation device, but in this modified example, a half-rotating type so-called half gantry 40 is exemplified as the irradiation device. Note that the right side of the paper in Fig. 3 will be described as the front side (front side) of the half gantry 40.

[0045] The half gantry 40 is equipped with an irradiation nozzle 18 capable of changing the irradiation direction of the charged particle beam B with respect to an isocenter C. This irradiation nozzle 18 moves in the circumferential direction at a position equidistant from the isocenter C, with the isocenter C as the center, where a patient P as an irradiation target is located. The range of this movement is 240 degrees or less. In other words, the half gantry 40 refers to an irradiation device whose rotation range is two-thirds or less of the entire circumference (240 degrees or less). This half gantry 40 is smaller than a full-circumference rotating gantry.

[0046] The irradiation nozzle 18 of the half gantry 40 of this modification is set to move in a circumferential direction over a range of 180 degrees with the isocenter C as the center. For example, when the position of the irradiation nozzle 18 when irradiating the charged particle beam B in the horizontal direction is set to 0 degrees, the irradiation nozzle 18 can move over a range of +90 degrees to -90 degrees. The irradiation nozzle 18 can rotate 90 degrees in one direction and then the other direction in the circumferential direction to an arbitrary angle of 180 degrees in total. For example, the irradiation nozzle 18 moves along a C-shaped rail 42 that is C-shaped in a side view and is provided on the housing 41 of the half gantry 40.

[0047] The irradiation direction of the charged particle beam B with respect to the isocenter C can be changed within the range of movement of the irradiation nozzle 18. For example, when the irradiation nozzle 18 is at a position of +90 degrees, the charged particle beam B is irradiated from directly above the patient P. Also, when the irradiation nozzle 18 is at a position of -90 degrees, the charged particle beam B is irradiated from directly below the patient P.

[0048] The patient P is placed on a movable stage 43. This movable stage 43 is supported by a moving arm 44 and moves with the patient P placed thereon, to position the affected area of ​​the patient P at the isocenter C. By moving this movable stage 43, the patient P can be moved to the irradiation position of the charged particle beam B and aligned. Therefore, the charged particle beam B can be irradiated to the diseased tissue of the patient P with optimal accuracy.

[0049] The movable stage 43 allows the patient P to enter through an open portion of the half gantry 40 and be positioned at the isocenter C. For example, the movable stage 43 carrying the patient P can be entered from the front direction of the half gantry 40 (the direction of arrow D in FIG. 3). In this way, the patient P can be entered from an appropriate direction and be positioned at the isocenter C.

[0050] In the first embodiment, a first building 21 in which devices such as the linear accelerator 3 and the circular accelerator 4 are installed, and a second building 22 in which devices such as the rotating gantry 7 and the half gantry 40 are installed are constructed separately. In this way, the particle beam irradiation system 1 can be efficiently installed in a limited area such as an urban area, and this contributes to reducing construction costs.

[0051] Second embodiment Next, a second embodiment will be described with reference to Fig. 4. Note that the same components as those shown in the above-described embodiment are denoted by the same reference numerals and will not be described again.

[0052] In the second embodiment, a fixed irradiation device 50 is exemplified as an irradiation device. The fixed irradiation device 50 has a fixed angle at which a charged particle beam is emitted toward an isocenter C where a patient P as an irradiation target is placed. For example, the fixed irradiation device 50 that emits a charged particle beam toward the patient P from a vertical direction, which is an angle other than the horizontal direction, is provided in the irradiation chamber 25.

[0053] In the second embodiment, a first building 21, a second building 22, and a connection section 23 are constructed on one building site 33. The first building 21 has one floor above ground. The second building 22 has one floor above ground and one floor underground. Furthermore, the connection section 23 is constructed on the ground.

[0054] The accelerator room 24, in which devices such as the circular accelerator 4 are installed, is formed on the first above-ground floor of the first building 21. On the other hand, the irradiation room 25, in which the fixed irradiation device 50 is installed, is formed on the first basement floor of the second building 22. In other words, the accelerator room 24 and the irradiation room 25 are on different floors, and the height of the floor F of the accelerator room 24 and the floor F of the irradiation room 25 are different. Note that there are cases in which the accelerator room 24 is provided on the first basement floor and the irradiation room 25 is provided on the second basement floor.

[0055] The main transportation line 5 extends from the accelerator room 24 in the first building 21 through a connection part 23 to a prescribed room 28 on the first floor above ground in the second building 22. The sub-transportation line 6 is bent downward from this room 28 and extends to an irradiation room 25 on the first basement floor of the second building 22. The trajectory of the charged particle beam is bent downward by the bending electromagnets 14 of the sub-transportation line 6.

[0056] In the second embodiment, when a charged particle beam is injected from the sub-transport line 6 in a vertical or oblique direction into the fixed irradiation device 50, the number of bending electromagnets 14 can be reduced. For example, when the accelerator room 24 and the irradiation room 25 are on the same floor, the trajectory of the charged particle beam flying in the horizontal direction from the circular accelerator 4 must be once directed upward, then directed horizontally, and then directed downward. In other words, at least three bending electromagnets 14 are required. However, in the second embodiment, one bending electromagnet 14 for directing the trajectory of the charged particle beam flying in the horizontal direction from the circular accelerator 4 downward is sufficient.

[0057] Third embodiment Next, a third embodiment will be described with reference to Figures 5 to 8. Note that the same components as those shown in the above-described embodiments are denoted by the same reference numerals and will not be described again.

[0058] As shown in Fig. 5, in the third embodiment, a slit-type irradiation device 51 is exemplified as the irradiation device. The first building 21 and the second building 22 are constructed on one side and the other side of two adjacent building sites 31, 32 with a road site 30 in between. The first building 21 has one basement floor. The second building 22 has one floor above ground and one basement floor. Furthermore, the connection part 23 is constructed underground.

[0059] The accelerator room 24 in which devices such as the circular accelerator 4 are installed is formed on the first basement floor of the first building 21. The irradiation room 25 in which the slit-type irradiation device 51 is installed is formed on the first basement floor of the second building 22.

[0060] Here, the first basement floor of the first building 21 and the first basement floor of the second building 22 are different in construction depth even though they are the same floor, and the height of the floor F of the accelerator room 24 and the floor F of the irradiation room 25 are different. For example, the floor F of the accelerator room 24 is provided at a higher position than the floor F of the irradiation room 25. In other words, the slit-type irradiation device 51 is installed at a lower position than the circular accelerator 4.

[0061] The slit-type irradiation device 51 will be described with reference to Fig. 6 and Fig. 7. The right side of Fig. 6 is the front side (forward side) of the slit-type irradiation device 51. If the direction in which the vacuum duct 8 of the sub-transport line 6 extends and the direction in which the charged particle beam B comes is defined as the X direction, the vertical direction of the paper perpendicular to this is defined as the Y direction, and the direction perpendicular to these is defined as the Z direction.

[0062] First, a deflection electromagnet 52 is provided at the end of the vacuum duct 8 of the sub-transportation line 6. An expansion duct 53 is provided which spreads out in a triangular shape (fan shape) in side view from the deflection electromagnet 52. The expansion duct 53 spreads out in the Y direction from the end of the vacuum duct 8 of the sub-transportation line 6. A main body 54 is connected to the tip of this expansion duct 53. The main body 54 has a vertically long rectangular shape in side view. The inside of the expansion duct 53 and the main body 54 forms an enclosed space having a vacuum degree continuous with the vacuum duct 8 of the sub-transportation line 6.

[0063] Inside the main body 54, a number of bending electromagnets 55 (FIG. 7) are provided to deflect the charged particle beam B incident from a wide angle range and focus it on the isocenter C. These bending electromagnets 55 generate an effective magnetic field region R (FIG. 6).

[0064] For example, a pair of bending electromagnets 55 are provided in the Z direction inside the main body 54. The two sets of bending electromagnets 55 are arranged side by side in the Y direction. One set of bending electromagnets 55 generates one effective magnetic field region R. In the example of Fig. 6, two sets of bending electromagnets 55, one above the other, can generate two effective magnetic field regions R.

[0065] The effective magnetic field region R is generated to have a crescent shape in a side view. The trajectory of the charged particle beam B can be controlled by controlling the strength of the effective magnetic field region R. The charged particle beam B can be irradiated at any angle centered on the isocenter C. For example, if the inclination of the reference trajectory when the trajectory of the charged particle beam B is not deflected is set to 0 degrees, the irradiation angle of the charged particle beam B can be changed in the range from +85 degrees to -85 degrees centered on the isocenter C.

[0066] The reference trajectory refers to a trajectory in which the charged particle beam B flies straight from the vacuum duct 8 toward the isocenter C.

[0067] In the example of FIG. 6, the two effective magnetic field regions R, upper and lower, have the same shape and the same strength. In other words, the effective magnetic field regions R are generated symmetrically, but other configurations are also possible. For example, the effective magnetic field region R may be asymmetrical. In other words, the two effective magnetic field regions R, upper and lower, may have different shapes and strengths. Furthermore, a configuration in which one effective magnetic field region R is generated on either the upper or lower side may be possible. Note that the center of the range of the angle of the charged particle beam B that changes in the circumferential direction around the isocenter C may be shifted from the reference trajectory of the charged particle beam B.

[0068] The front side of the main body 54 has a recess 56 that is recessed in a semicircular shape in a side view. The patient P is placed in this recess 56. The patient P can be placed at the isocenter C by having the movable stage 43 enter through the recess 56 on the front side of the main body 54. For example, the movable stage 43 carrying the patient P can be entered from the front direction of the slit-type irradiation device 51 (the direction of arrow D in FIG. 6). In this way, the patient P can be placed at the isocenter C by entering from an appropriate direction.

[0069] A slit 57 is formed on the front side of the main body 54, extending in the circumferential direction centered on an isocenter C where a patient P as an irradiation target is placed. For example, a vertically long slit 57 (FIG. 7) is formed. The slit-type irradiation device 51 emits the charged particle beam B from this slit 57 toward the isocenter C at an arbitrary angle. The slit 57 is closed with an extremely heat-resistant and extremely cold-resistant polyimide film, and a vacuum is maintained inside the main body 54 in a state where the charged particle beam B can pass through.

[0070] The slit-type irradiation device 51 includes an irradiation nozzle 18 capable of changing the irradiation direction of the charged particle beam B with respect to an isocenter C. The irradiation nozzle 18 moves in the circumferential direction at a position equidistant from the isocenter C, with the isocenter C being the center, where a patient P as an irradiation target is located. The range of this movement is 180 degrees or less, for example, 170 degrees or less.

[0071] For example, when the inclination of the reference orbit of the charged particle beam B is 0 degrees, the irradiation nozzle 18 can move in the range of +85 degrees to -85 degrees. It can rotate 85 degrees in one direction and 85 degrees in the other direction in the circumferential direction, and can rotate an arbitrary angle of 170 degrees in total. For example, the irradiation nozzle 18 moves along a C-shaped rail 58 that is C-shaped in a side view and is provided in a recess 56 of a main body 54 of the slit-type irradiation device 51.

[0072] The irradiation nozzle 18 moves so as to follow the shape (boundary shape) of the exit side of the effective magnetic field region R in a side view. The charged particle beam B traveling from the exit side of the effective magnetic field region R toward the isocenter C passes through the irradiation nozzle 18, and the traveling direction of the charged particle beam B is finely adjusted by the irradiation nozzle 18.

[0073] 6 to 7, the X direction of the slit-type irradiation device 51 is shown aligned with the horizontal direction to facilitate understanding. However, when the slit-type irradiation device 51 is actually installed, the entire slit-type irradiation device 51 is inclined as shown in Fig. 8. For example, the main body 54 is installed on the floor surface F with the longitudinal direction (Y direction) of the main body 54 inclined.

[0074] In the third embodiment, the upper part of the main body 54 is tilted toward the patient P. The irradiation range of the charged particle beam B is a range of 170 degrees centered on the isocenter C, but since the slit-type irradiation device 51 is tilted, the charged particle beam B can be irradiated from directly above the patient P.

[0075] That is, the slit-type irradiation device 51 is installed in a tilted state so that the reference trajectory when the trajectory of the charged particle beam B is not deflected by the slit-type irradiation device 51 is tilted from the horizontal direction (horizontal axis). In this way, the range of angles at which the charged particle beam B is irradiated to the patient P who is the irradiation target becomes practical.

[0076] Furthermore, by arranging the slit-type irradiation device 51 with its longitudinal direction inclined with respect to the floor surface F of the irradiation room 25, the ceiling height required for arranging the slit-type irradiation device 51 can be kept low.

[0077] In the third embodiment, the inclination angle of the reference trajectory (X-axis) of the charged particle beam B with respect to the horizontal axis is 25 degrees. Note that this angle may be in the range of 20 degrees to 90 degrees.

[0078] When such a slit-type irradiation device 51 is tilted, the floor surface F of the irradiation chamber 25 is provided at a position lower than the floor surface F of the accelerator chamber 24, as shown in Fig. 5. In this way, when the charged particle beam B is injected from the sub-transportation line 6 in an oblique direction (or vertical direction) into the slit-type irradiation device 51, the number of bending electromagnets 14 of the sub-transportation line 6 can be reduced.

[0079] Fig. 9 shows a main transport line 5 and a sub-transport line 6 as beam transport lines in a conventional example (comparative example). In this conventional example, it is assumed that the floor surface F of the accelerator room 24 and the floor surface F of the irradiation room 25 are at the same height, and the slit-type irradiation device 51 is installed in an inclined state. In this case, the vacuum duct 8 extending from the main transport line 5 must first extend horizontally, then bend diagonally upward at the sub-transport line 6, and then extend horizontally and bend diagonally downward. Therefore, in the example of Fig. 9, three bending electromagnets 14 are required in the sub-transport line 6.

[0080] 8, the vacuum duct 8 extending from the main transportation line 5 first extends horizontally, and then bends obliquely downward in the vicinity of the slit-type irradiation device 51 in the sub-transportation line 6. In other words, one bending electromagnet 14 in the sub-transportation line 6 is sufficient.

[0081] In the third embodiment, the upper part of the main body 54 of the slit-type irradiation device 51 is tilted toward the patient P, but the upper part of the main body 54 may be tilted away from the patient P. In addition, the slit-type irradiation device 51 may be used without being tilted.

[0082] (Fourth embodiment) Next, a fourth embodiment will be described with reference to Fig. 10. Note that the same components as those shown in the above-mentioned embodiments are denoted by the same reference numerals and the duplicated description will be omitted.

[0083] In the fourth embodiment, a slit-type irradiation device 51 is exemplified as an irradiation device. The slit-type irradiation device 51 is installed in a tilted state. In the fourth embodiment, the upper part of the main body 54 is tilted away from the patient P, which is the opposite to the third embodiment (FIG. 8).

[0084] In the fourth embodiment, the first building 21 and the second building 22 are constructed on one and the other of two adjacent building sites 31, 32, with a road site 30 in between. The first building 21 has one basement floor. The second building 22 has one aboveground floor. Furthermore, the connection part 23 is constructed underground. An underground trench 29 continuing from the connection part 23 is formed in the basement of the second building 22.

[0085] The accelerator room 24, in which devices such as the circular accelerator 4 are installed, is formed on the first basement floor of the first building 21. The irradiation room 25, in which a slit-type irradiation device 51 is installed, is formed on the first aboveground floor of the second building 22. In other words, the accelerator room 24 and the irradiation room 25 are on different floors, and the height of the floor F of the accelerator room 24 and the floor F of the irradiation room 25 are different.

[0086] For example, the floor surface F of the accelerator room 24 is provided at a lower position than the floor surface F of the irradiation room 25. In other words, the slit-type irradiation device 51 is installed at a higher position than the circular accelerator 4.

[0087] The main transportation line 5 extends from the accelerator room 24 in the first building 21 through a connection 23 to an underground trench 29 in the second building 22. The sub-transportation line 6 is bent diagonally upward from this underground trench 29 and extends to an irradiation chamber 25 on the first floor of the second building 22. The trajectory of the charged particle beam is bent diagonally upward by the bending electromagnets 14 of the sub-transportation line 6.

[0088] When such a slit-type irradiation device 51 is tilted, the floor surface F of the irradiation chamber 25 is provided at a position higher than the floor surface F of the accelerator chamber 24. In this way, when a charged particle beam is injected from the sub-transportation line 6 obliquely (or vertically) into the slit-type irradiation device 51, the number of bending electromagnets 14 of the sub-transportation line 6 can be reduced.

[0089] In the fourth embodiment, the upper part of the main body 54 of the slit-type irradiation device 51 is tilted away from the patient P, but the upper part of the main body 54 may be tilted toward the patient P. In addition, the slit-type irradiation device 51 may be used without being tilted.

[0090] Fifth embodiment Next, a fifth embodiment will be described with reference to Fig. 11. Note that the same components as those shown in the above-mentioned embodiments are given the same reference numerals and the duplicated description will be omitted.

[0091] In the fifth embodiment, a slit-type irradiation device 51 is exemplified as the irradiation device. Furthermore, one building 35 is constructed on one building site 34. The building 35 has one floor above ground and one floor underground.

[0092] The accelerator room 24, in which devices such as the circular accelerator 4 are installed, is formed on the first above-ground floor of a building 35. On the other hand, the irradiation room 25, in which a slit-type irradiation device 51 is installed, is formed on the first basement floor of the building 35. In other words, the accelerator room 24 and the irradiation room 25 are on different floors, and the height of the floor F of the accelerator room 24 and the floor F of the irradiation room 25 are different.

[0093] The main transport line 5 extends from the accelerator room 24 on the ground in a building 35 to the irradiation room 25 underground. The charged particle beam is guided to the irradiation room 25 while its trajectory is bent by the bending electromagnets 12 of the main transport line 5.

[0094] The main transport line 5 extends to the vicinity of the slit-type irradiation device 51 and extends horizontally at a position higher than the slit-type irradiation device 51. The sub-transport line 6 extends obliquely downward from the main transport line 5 and is connected to the slit-type irradiation device 51. The trajectory of the charged particle beam is bent downward by the bending electromagnet 14 of the sub-transport line 6.

[0095] When such a slit-type irradiation device 51 is tilted, the slit-type irradiation device 51 is provided at a position lower than the main transportation line 5. In this way, when a charged particle beam is injected from the sub-transportation line 6 in an oblique direction (or vertical direction) into the slit-type irradiation device 51, the number of deflection electromagnets 14 of the sub-transportation line 6 can be reduced.

[0096] The present invention has been described above based on the first to fifth embodiments, but the configuration applied in any of the embodiments may be applied to other embodiments, and the configurations applied in each embodiment may be combined.

[0097] In the above embodiment, the subject of irradiation with the charged particle beam is a human patient P, but other aspects may be used. For example, animals such as dogs and cats may be the subject of irradiation. The particle beam irradiation system 1 may be used when administering radiation therapy to these animals.

[0098] According to at least one of the embodiments described above, by providing the first building 21 and the second building 22, the particle beam irradiation system 1 can be efficiently installed in a limited area such as an urban area, and can contribute to reducing construction costs.

[0099] Although some embodiments of the present invention have been described, these embodiments are presented as examples and are not intended to limit the scope of the invention. These embodiments can be implemented in various other forms, and various omissions, substitutions, modifications, and combinations can be made without departing from the spirit of the invention. These embodiments or modifications thereof are within the scope of the invention and its equivalents as described in the claims, as well as within the scope and spirit of the invention. [Explanation of symbols]

[0100] Reference Signs List 1...particle beam irradiation system, 2...ion generator, 3...linear accelerator, 4...circular accelerator, 5...main transport line, 6...sub-transport line, 7...rotating gantry, 8...vacuum duct, 9...high frequency acceleration cavity, 10...bending electromagnet, 11...converging electromagnet, 12...bending electromagnet, 13...converging electromagnet, 14...bending electromagnet, 15...converging electromagnet, 16...bending electromagnet, 17...converging electromagnet, 18...irradiation nozzle, 21...first building, 22...second building, 23...connection, 24...accelerator room, 25...irradiation room, 26...accelerator control room, 27...irradiation nozzle Shooting control room, 28...room, 29...underground trench, 30...road area, 31, 32, 33, 34...building area, 35...building, 40...half gantry, 41...casing, 42...C-shaped rail, 43...mobile platform, 44...mobile arm, 50...fixed type irradiation device, 51...slit-type irradiation device, 52...deflection electromagnet, 53...expansion duct, 54...main body, 55...deflection electromagnet, 56...recess, 57...slit, 58...C-shaped rail, B...charged particle beam, C...isocenter, F...floor, G...ground, P...patient, R...effective magnetic field area.

Claims

1. The first building, a second building different from the first building; an accelerator provided in the first building and configured to accelerate a charged particle beam; a beam transport line for guiding the charged particle beam accelerated by the accelerator; an irradiation device provided in the second building and configured to irradiate an irradiation target with the charged particle beam guided by the beam transport line; Equipped with Particle beam irradiation system.

2. The first building is constructed on one of two building sites adjacent to each other across a road site, and the second building is constructed on the other site. The particle beam irradiation system according to claim 1 .

3. In the beam transport line, a portion connecting the first building and the second building is linear. The particle beam irradiation system according to claim 1 or 2.

4. a portion of the beam transport line connecting the first building and the second building is provided underground; The particle beam irradiation system according to claim 1 or 2.

5. the height of the floor of the accelerator room in which the accelerator is installed is different from the height of the floor of the irradiation room in which the irradiation device is installed; The particle beam irradiation system according to claim 1 or 2.

6. The accelerator room in which the accelerator is installed is on a different floor than the irradiation room in which the irradiation device is installed. The particle beam irradiation system according to claim 1 or 2.

7. The irradiation device is a fixed-type irradiation device in which an angle at which the charged particle beam is emitted toward an isocenter where the irradiation target is located is fixed and the charged particle beam is emitted at an angle other than a horizontal direction. The particle beam irradiation system according to claim 1 or 2.

8. the irradiation device includes an irradiation nozzle that moves around an isocenter where the irradiation target is located at a position equidistant from the isocenter and can change an irradiation direction of the charged particle beam with respect to the isocenter; The particle beam irradiation system according to claim 1 or 2.

9. the irradiation device includes an irradiation nozzle that moves in a circumferential direction around an isocenter on which the irradiation target is located at a position equidistant from the isocenter, the range of the movement being 240 degrees or less, and that can change the irradiation direction of the charged particle beam with respect to the isocenter; The particle beam irradiation system according to claim 1 or 2.

10. The irradiation device is a slit-type irradiation device in which a slit extending in a circumferential direction around an isocenter where the irradiation target is located is formed, and the charged particle beam is emitted from the slit toward the isocenter at an arbitrary angle. The particle beam irradiation system according to claim 1 or 2.

11. The irradiation device is installed in a tilted state so that a reference trajectory when the trajectory of the charged particle beam is not deflected by the irradiation device is tilted from a horizontal direction. The particle beam irradiation system according to claim 10.

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