Neutron capture therapy equipment

Abstract

To provide neutron capture therapy equipment in which a necessary space can be reduced while radiation leakage is suppressed.SOLUTION: In an underground layer 102, a cable 70 extending from the outside of a shield chamber 60 to the inside of the shield chamber 60 is provided. The cable 70 extends from the shield chamber 60 to an accelerator chamber 9. The cable 70 can be connected to an accelerator body 5A in the inside of the accelerator chamber 9. The shield chamber 60 has a lower radiation dose than that of the accelerator chamber 9. Even when a through hole is formed in a wall part 58 of the shield chamber 60, as compared to a case of forming a through hole in a wall part 53 of the accelerator chamber 9, radiation leakage can be suppressed. Since it is not necessary to form a through hole in the wall part 53 of the accelerator chamber 9, a thickness of the wall part 53 of the accelerator chamber 9 can be suppressed. By suppressing a thickness of the wall part 53 of the accelerator chamber 9, an area of the entire equipment can be reduced, and, if the area remains the same, a space obtained by an amount of reduced thickness of the wall part can be effectively utilized for other purposes.SELECTED DRAWING: Figure 4

Description

Technical Field

[0001] The present invention relates to neutron capture therapy equipment.

Background Art

[0002] As a neutron capture therapy for killing cancer cells by irradiating neutron rays, boron neutron capture therapy (BNCT: Boron Neutron Capture Therapy) using a boron compound is known. As a neutron capture therapy device used in such boron neutron capture therapy, Patent Document 1 describes a neutron capture therapy device including a cyclotron that emits a charged particle beam and a target that generates neutron rays when irradiated with the charged particle beam.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] Here, in a neutron capture therapy facility where the above-described neutron capture therapy device is provided, an accelerator or the like is housed in a shielding room so that radiation does not leak to the outside. The wall portion of such a shielding room is set to have a large thickness so that radiation does not leak to the outside. When extending a cable from the outside to such a shielding room, it is necessary to make a hole in the wall portion of the shielding room and arrange the cable in the hole. However, there is a possibility of radiation leakage from the hole, and when the thickness of the wall portion is increased to suppress the leakage, there is a problem that the facility becomes large.

[0005] Therefore, an object of the present invention is to provide a neutron capture therapy facility that can suppress radiation leakage and achieve space saving.

Means for Solving the Problems

[0006] In one embodiment, the neutron capture therapy facility of the present invention is a neutron capture therapy facility that irradiates a subject with neutron beams, and includes a first floor and a second floor that is below or above the first floor. The first floor includes an accelerator main body that emits particle beams, a target that generates neutron beams by irradiating particle beams, an irradiation unit that irradiates the neutron beams generated by the target to the subject, and a first shielding room that houses at least the accelerator main body. The second floor includes a second shielding room provided below or above the first shielding room. In the second floor, a cable extending from the outside of the second shielding room into the second shielding room is provided, and the cable extends from the second shielding room to the first shielding room.

[0007] In this neutron capture therapy facility, the first shielding room on the first floor houses at least the accelerator main body. Since the accelerator main body is a device that emits radiation, the radiation dose in the first shielding room is high. For example, assume that a cable is extended from the outside of the first shielding room into the first shielding room on the first floor. At this time, it is necessary to form a through hole that penetrates to the outside in the wall portion of the first shielding room with a high radiation dose. In this case, there is a possibility that radiation leaks from the through hole. And if the thickness of the wall portion is increased so that radiation does not leak, the facility becomes larger. On the other hand, in the second floor, a cable extending from the outside of the second shielding room into the second shielding room is provided. And the cable extends from the second shielding room to the first shielding room. Thereby, the cable can be connected to the accelerator main body etc. in the first shielding room. The second shielding room has a lower radiation dose than the first shielding room. Therefore, even if a through hole is formed in the wall portion of the second shielding room, radiation leakage can be suppressed as compared with the case of forming a through hole in the wall portion of the first shielding room. Also, since it is not necessary to form a through hole in the wall portion of the first shielding room, the thickness of the wall portion of the first shielding room can be suppressed. By suppressing the thickness of the first shielding room in this way, the area of the entire facility can be reduced, or if the area is the same, the space corresponding to the reduction in the thickness of the wall portion can be effectively utilized for other purposes. From the above, it is possible to suppress radiation leakage and achieve space saving.

[0008] In the second shielding room, an ion source connected to the accelerator main body in the first shielding room and supplying ions to the accelerator main body may be provided. Since the radiation dose of the ion source is less than that of the accelerator main body, leakage of radiation from the second shielding room to the outside can be suppressed.

[0009] A cooling device may be provided on the second floor. In this case, since equipment can be arranged on each of the two floors, the area can be reduced.

[0010] The cable is arranged in the through-hole in the wall of the second shielding room, and the through-hole may have a crank-like shape. In this case, when radiation passes through the through-hole in the wall, its progress is inhibited by the crank-like shape, making it difficult for the radiation to leak to the outside.

[0011] The ion source may be provided at a position where at least a part of it overlaps with the accelerator main body when viewed from the vertical direction. In this case, the ion source can supply ions to the accelerator main body immediately.

Advantages of the Invention

[0012] According to the present invention, it is possible to provide a neutron capture therapy facility that suppresses radiation leakage and achieves space saving.

Brief Description of the Drawings

[0013]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Embodiments for Carrying Out the Invention

[0014] Hereinafter, a neutron capture therapy apparatus according to an embodiment of the present invention will be described in detail with reference to the drawings. Also, in the description, the terms "upper" and "lower" may be used, which correspond to the upper and lower directions of the drawings.

[0015] First, the overall configuration of the neutron capture therapy facility 1 will be described with reference to FIGS. 1 and 2. The neutron capture therapy facility 1 includes a BNCT system that performs boron neutron capture therapy (BNCT). Neutron capture therapy is a treatment method in which a neutron beam is irradiated onto a site where boron has accumulated in a patient Q (the irradiated object) administered with boron ( 10 B), thereby treating the lesion (e.g., tumor, etc.) of the patient.

[0016] The neutron capture therapy facility 1 includes a treatment room 3 that houses the patient Q placed on the treatment table 2 and irradiates the patient Q with a neutron beam, an accelerator room 9 that houses an accelerator 5 that generates a particle beam P and a transport line 7 that transports the particle beam P emitted from the accelerator 5 to an irradiation unit 11 described later, and an irradiation unit 11 that receives the particle beam P from the transport line 7 and irradiates the patient Q with the generated neutron beam N. The accelerator 5 includes an accelerator main body 5A that accelerates particles (ions) and an ion source 5B that supplies particles (ions) to the accelerator main body 5A. The accelerator main body 5A includes main components of the accelerator 5, such as acceleration electrodes and yokes. The accelerator 5 is, for example, a cyclotron that accelerates charged particles (e.g., protons) and emits a particle beam P (e.g., a proton beam). Note that the accelerator 5 is not limited to a cyclotron and may be other accelerators such as a synchrotron, a synchrocyclotron, a linac, or an electrostatic accelerator. The treatment room 3 and the accelerator room 9 are closed spaces surrounded by a shielding wall W, and the shielding wall W is a concrete wall for shielding radiation. The irradiation unit 11 is arranged so as to be embedded in the shielding wall W that partitions the treatment room 3 and the accelerator room 9. Note that the irradiation unit 11 may be arranged in the accelerator room 9 or the treatment room 3 without being embedded in the shielding wall W. Furthermore, the treatment room 3 and the accelerator room 9 may be combined into one room without being separated by the shielding wall W.

[0017] Furthermore, the neutron capture therapy facility 1 includes a preparation room 10 adjacent to the treatment room 3. The preparation room 10 is isolated from the treatment room 3 by a shielding wall W. A communication room 13 allowing passage between the treatment room 3 and the preparation room 10 is provided through the shielding wall W. And, shielding doors 15 that can be opened and closed are provided at the boundary between the communication room 13 and the treatment room 3 and at the boundary between the communication room 13 and the preparation room 10. The treatment table 2 is movable between the treatment room 3 and the preparation room 10 through the communication room 13. In the preparation room 10, preparatory work prior to treatment is performed. Specifically, the preparation room 10 is a room for carrying out operations necessary for irradiating the patient Q with neutron rays N in the treatment room 3. In the preparation room 10, for example, restraint of the patient Q on the treatment table 2 and simulation of alignment between the collimator 21 and the patient Q are carried out.

[0018] As shown in FIG. 2, the neutron capture therapy facility 1 includes a target T and an irradiation unit 11. The target T is a member that generates neutron rays N by being irradiated with particle rays P. The irradiation unit 11 is a device that irradiates the patient Q with the neutron rays N generated by the target T. The irradiation unit 11 includes a moderator 17 that decelerates (lowers the energy of) the generated neutron rays N and a shield 19 that covers at least a part of the periphery of the moderator 17 to shield radiation. The shield 19 shields secondary radiation such as gamma rays generated by the moderator 17. The neutron rays N emitted from the moderator 17 pass through a collimator 21 (irradiation port) provided on the treatment table 2 and irradiate the patient Q. The collimator 21 can change the irradiation range of the neutron rays N irradiated to the patient Q.

[0019] The target T generates neutron rays N when irradiated with the particle rays P emitted by the accelerator 5. The target T is made of a material such as beryllium (Be) and has a disk shape. Note that instead of the target T made of beryllium, a target made of lithium (Li), tantalum (Ta), or tungsten (W) may be used, and the size of the target can also be appropriately changed.

[0020] In FIG. 2, the patient Q on the treatment table 2 is in a lying position, but the posture of the patient Q is not particularly limited, and the neutron beam N may be irradiated to the seated patient Q.

[0021] Next, with reference to FIGS. 1, 3, and 4, the layout of the neutron capture therapy facility 1 will be described in more detail. In the following description, XY coordinates are set for the neutron capture therapy facility 1 for the description. The X-axis and the Y-axis are set in the horizontal direction. The Y-axis is the direction in which the accelerator 5 emits the particle beam P. The downstream side of the particle beam P is defined as the positive side in the Y-axis direction. The X-axis direction is perpendicular to the Y-axis direction. The side where the preparation room 10 is provided with respect to the treatment room 3 is defined as the positive side in the X-axis direction. FIG. 3 is a cross-sectional view taken along line III-III shown in FIG. 1. FIG. 4 is a cross-sectional view taken along line IV-IV shown in FIG. 3.

[0022] As shown in FIGS. 3 and 4, the building 100 of the neutron capture therapy facility 1 includes a first floor 101 (the first floor) and a basement floor 102 (the second floor) which is below the first floor 101. The first floor 101 is a floor provided above the ground GD. The basement floor 102 is a floor provided below the ground GD. FIG. 1 shows the state of the first floor 101.

[0023] As shown in FIG. 1, the first floor 101 includes the aforementioned accelerator room 9 (the first shielding room), the aforementioned treatment room 3, the aforementioned preparation room 10, and the equipment front room 30. The equipment front room 30 is provided at a position adjacent to the accelerator room 9 on the positive side in the X-axis direction.

[0024] The accelerator room 9 on the first floor 101 houses the accelerator main body 5A, the transport line 7, and the target T. Also, a part of the irradiation unit 11 is housed in the accelerator room 9. The accelerator main body 5A is provided near the negative-side end in the Y-axis direction in the accelerator room 9. The target T and the irradiation unit 11 are provided near the positive-side end in the Y-axis direction of the accelerator room 9. A part of the irradiation unit 11 is provided so as to be embedded in the wall portion 52 between the accelerator room 9 and the treatment room 3. Some components of the irradiation unit 11 are arranged in the accelerator room 9. The equipment front room 30 on the first floor 101 houses the control device for controlling the accelerator 5 and the irradiation unit 11, and the device 55 including a power supply device and the like.

[0025] In the accelerator room 9, devices that generate radiation such as the accelerator main body 5A and the target T are housed. The thickness of each wall portion of the accelerator room 9 is large. Therefore, the thickness of the wall portion 52 between the accelerator room 9 and the treatment room 3 is large, and the thickness of the wall portion 53 between the accelerator room 9 and the equipment front room 30 is large. Also, since the neutron beam N enters the treatment room 3, the thickness of each wall portion is large. The thickness of the wall portion 54 between the treatment room 3 and the preparation room 10 is large. Although not particularly limited, these wall portions with large thicknesses are set to a thickness of about 250 cm. The equipment front room 30 and the preparation room 10 do not have equipment that generates radiation, and radiation does not enter either. Therefore, the thickness of the wall portions other than the wall portions 53 and 54 is small. These wall portions with small thicknesses are set to a thickness of about 30 cm.

[0026] As shown in FIG. 4, the basement floor 102 includes a shielding room 60 (second shielding room) and a pit 61. The shielding room 60 is provided below the accelerator room 9 on the first floor 101. The pit 61 is provided below the equipment anteroom 30. The shielding room 60 extends horizontally and is vertically separated from the accelerator room 9 by a wall portion 56 that constitutes the floor of the accelerator room 9. The pit 61 extends horizontally and is vertically separated from the equipment anteroom 30 by a wall portion 57 that constitutes the floor of the equipment anteroom 30. The pit 61 and the shielding room 60 are separated in the X-axis direction by a wall portion 58. The size of the shielding room 60 in the X-axis direction may be substantially the same as the size of the accelerator room 9. The size of the shielding room 60 in the Y-axis direction may be substantially the same as the size of the accelerator room 9 (see FIG. 3). However, the shielding room 60 only needs to overlap at least a part of the accelerator room 9 when viewed from the vertical direction, and the size and position are not particularly limited.

[0027] In the shielding room 60, an ion source 5B is provided, which is connected to the accelerator main body 5A in the accelerator room 9 and supplies ions to the accelerator main body 5A. The ion source 5B is provided at a position where at least a part of it overlaps the accelerator main body 5A when viewed from the vertical direction. Therefore, the ion source 5B is provided near the end on the negative side in the Y-axis direction of the shielding room 60. In this embodiment, when viewed from the vertical direction, the entire ion source 5B overlaps the accelerator main body 5A. However, when viewed from the vertical direction, a part of the ion source 5B may be arranged so as to protrude from the accelerator main body 5A. The ion source 5B extends upward from the shielding room 60, penetrates the wall portion 56, and is connected to the lower surface side of the accelerator main body 5A. The ion source 5B is arranged between a pair of wall portions 65 (see FIG. 4) that are arranged to face each other and be separated from each other in the X-axis direction. A through hole for extending the ion source 5B in the vertical direction is formed between the upper end portions of the pair of wall portions 65.

[0028] In the shielding chamber 60, a cooling device 62 is provided near the positive-side end in the Y-axis direction. The cooling device 62 is a device for cooling the target T, as well as the accelerator main body 5A, the ion source 5B, and the transport line 7, and is provided at a position corresponding to the lower side of the target T. For example, when the replacement of the target T in the accelerator chamber 9 is automated (fully automated or with some manual work), a large-scale target T recovery mechanism needs to be provided below the target T in the shielding chamber 60. On the other hand, when the replacement of the target T in the accelerator chamber 9 is manual work by an operator or the like, the large-scale recovery mechanism can be omitted. In such a case, the cooling device 62 can be arranged in the area below the target T in the shielding chamber 60.

[0029] Since the shielding chamber 60 is not provided with a device that generates radiation such as the accelerator main body 5A, the degree of activation is lower than that of the accelerator chamber 9. The pit 61 is also not provided with a device that generates radiation such as the accelerator main body 5A, so the degree of activation is lower than that of the accelerator chamber 9.

[0030] Here, the device 55 in the device pre-chamber 30 needs to transmit control signals and supply power to the accelerator main body 5A and the irradiation unit 11 accommodated in the accelerator chamber 9. The neutron capture therapy facility 1 electrically connects the device 55 in the device pre-chamber 30, the accelerator main body 5A, and the irradiation unit 11 using a cable 70 (see FIGS. 1 and 4).

[0031] As shown in FIG. 1, in the device pre-chamber 30 on the first floor 101, the end of the cable 70 is connected to the device 55. The cable 70 extends from the device 55 to the relay part 71 in the device pre-chamber 30. As shown in FIG. 4, the cable 70 extends downward from the relay part 71 in the device pre-chamber 30 on the first floor 101, penetrates the floor wall part 57, and extends to the pit 61 in the basement floor 102.

[0032] In the basement floor 102, the cable 70 extends from outside the pit 61, i.e., outside the shielding room 60, into the shielding room 60. The cable 70 penetrates through the wall portion 58 from the pit 61 in the basement floor 102 and extends into the shielding room 60. The cable 70 extends from the shielding room 60 to the accelerator room 9. The cable 70 extends upward from the shielding room 60 in the basement floor 102, penetrates through the wall portion 56, and extends to the accelerator room 9. In the accelerator room 9 on the first floor 101, the end of the cable 70 is connected to the accelerator main body 5A. Also, the end of the cable 70 is connected to the irradiation unit 11 (see FIG. 1).

[0033] FIG. 5 is an enlarged view of the through-hole 59 in the wall portion 58 that separates the pit 61 and the shielding room 60. The through-hole 59 is a hole for inserting the cable 70. As shown in FIG. 5, the cable 70 is disposed in the through-hole 59 of the wall portion 58 of the shielding room 60. The through-hole 59 penetrates the wall portion 58 in the thickness direction (here, the X-axis direction). The wall portion 58 has a side surface 58a on the shielding room 60 side and a side surface 58b on the pit 61 side. The through-hole 59 has a crank-like shape. The crank-like shape is a shape that draws a substantially S shape and has portions with different heights in the vertical direction. The through-hole 59 has a first portion 59a, a second portion 59b, and a third portion 59c. The first portion 59a is a portion that extends from the shielding room 60 side into the thickness direction inside. The second portion 59b is a portion that extends from the pit 61 side into the thickness direction inside. The third portion 59c is a portion that connects the first portion 59a and the second portion 59b inside the wall portion 58. The first portion 59a is disposed at a higher position than the second portion 59b. Each of the portions 59a, 59b extends along the X-axis direction at its respective height position. The third portion 59c extends so as to incline upward from the second portion 59b and is connected to the first portion 59a.

[0034] Next, the operation and effects of the neutron capture therapy facility 1 according to the present embodiment will be described.

[0035] In this neutron capture therapy facility 1, the accelerator room 9 on the first floor 101 houses at least the accelerator main body 5A. Since the accelerator main body 5A is a device that emits radiation, the radiation dose in the accelerator room 9 is high. For example, in the first floor 101, assume that a cable is extended from the outside of the accelerator room 9 into the accelerator room 9. Specifically, as shown by the two-dot chain line in FIG. 1, the cable 170 extends from the equipment pre-chamber 30 through the wall portion 53 into the accelerator room 9. At this time, it is necessary to form a through-hole that penetrates to the outside in the wall portion 53 of the accelerator room 9 where the radiation dose is high. In this case, there is a possibility that radiation leaks from the through-hole. And if the thickness of the wall portion 53 is increased so that radiation does not leak, the facility becomes larger. On the other hand, in the basement floor 102, a cable 70 is provided that extends from the outside of the shielding room 60 into the shielding room 60. And the cable 70 extends from the shielding room 60 to the accelerator room 9. Thereby, the cable 70 can be connected to the accelerator main body 5A etc. in the accelerator room 9. The shielding room 60 has a lower radiation dose than the accelerator room 9. Therefore, even if a through-hole is formed in the wall portion 58 of the shielding room 60, radiation leakage can be suppressed as compared with the case of forming a through-hole in the wall portion 53 of the accelerator room 9. Also, since it is not necessary to form a through-hole in the wall portion 53 of the accelerator room 9, the thickness of the wall portion 53 of the accelerator room 9 can be suppressed. In this way, by suppressing the thickness of the wall portion 53 of the accelerator room 9, the area of the entire facility can be reduced, or if the area is the same, the space corresponding to the reduction in the thickness of the wall portion can be effectively utilized for other purposes. From the above, radiation leakage can be suppressed and space saving can be achieved.

[0036] The shielding room 60 may be provided with an ion source 5B that is connected to the accelerator main body 5A in the accelerator room 9 and supplies ions to the accelerator main body 5A. Since the radiation dose of the ion source 5B is less than that of the accelerator main body 5A, leakage of radiation from the shielding room 60 to the outside can be suppressed.

[0037] A cooling device 62 may be provided in the basement floor 102. In this case, since equipment can be arranged on each of the two floors, the area can be reduced.

[0038] The cable 70 is disposed in the through-hole 59 of the wall portion 58 of the shielding chamber 60, and the through-hole 59 may have a crank-like shape. In this case, when radiation passes through the through-hole 59 of the wall portion 58, its progress is inhibited by the crank-like shape, making it difficult to leak to the outside.

[0039] The ion source 5B may be provided at a position where at least a part thereof overlaps with the accelerator main body 5A when viewed from the vertical direction. In this case, the ion source 5B can immediately supply ions to the accelerator main body 5A.

[0040] As described above, an embodiment of the present invention has been described. However, the present invention is not limited to the above embodiment, and may be modified without changing the gist described in each claim.

[0041] For example, the layouts shown in FIGS. 1, 3, and 4 are merely examples and may be changed as appropriate. Also, the devices arranged in each shielding chamber may be changed or omitted as appropriate. Accordingly, the arrangement of the cable 70 and the like may also be changed as appropriate within the scope of the gist of the present invention. It is sufficient that at least the accelerator main body 5A is accommodated in the accelerator chamber 9, and a part of the target T and the irradiation unit 11 may not be accommodated in the accelerator chamber 9.

[0042] For example, although the cooling device 62 was arranged in the same room as the ion source 5B, it may be arranged in a different room.

[0043] In the above embodiment, the second shielding chamber was provided below the first shielding chamber in which the accelerator main body 5A can be provided. Instead of this, the second shielding chamber may be provided above the first shielding chamber.

[0044] In the above-described embodiment, the case where the second layer, which is the lower layer, is the basement layer has been exemplified. However, the second layer does not necessarily have to be the basement layer and may be a layer on the ground GD. In this case, the first layer corresponds to the second floor of the building, and the second layer corresponds to the first floor of the building. Furthermore, both the first layer and the second layer may be basement layers. Also, another layer may be provided above the first layer, or another layer may be provided below the second layer.

Explanation of Reference Numerals

[0045] 1... Neutron capture therapy equipment, 5A... Accelerator main body, 5B... Ion source, 9... Accelerator room (first shielding room), 11... Irradiation unit, 58... Wall portion, 59... Through hole, 60... Shielding room (second shielding room), 62... Cooling device, 70... Cable, 101... First floor (first layer), 102... Basement layer (second layer).

Claims

1. A neutron capture therapy facility for irradiating a subject with neutron beams, comprising: a first layer; a second layer that is below or above the first layer, wherein the first layer includes: an accelerator body that emits particle beams; a target that generates the neutron beams by irradiating the particle beams; an irradiation unit that irradiates the neutron beams generated by the target onto the subject; a first shielding room that houses at least the accelerator body; wherein the second layer includes a second shielding room provided below or above the first shielding room, and in the second layer, a cable extending from outside the second shielding room into the second shielding room is provided, and the cable extends from the second shielding room to the first shielding room, the neutron capture therapy facility.

2. The neutron capture therapy facility according to claim 1, wherein an ion source connected to the accelerator body in the first shielding room and supplying ions to the accelerator body is provided in the second shielding room.

3. The neutron capture therapy facility according to claim 1, wherein a cooling device is provided in the second layer.

4. The neutron capture therapy facility according to claim 1, wherein the cable is disposed in a through-hole in a wall portion of the second shielding room, and the through-hole has a crank-like shape.

5. The neutron capture therapy facility according to claim 2, wherein the ion source is provided at a position where at least a part thereof overlaps with the accelerator body when viewed in the vertical direction.

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