Neutron capture therapy system

Abstract

The present application provides a neutron capture therapy system, which can avoid or reduce leakage of neutrons and other radiation at a place where a shielding wall or a floor is penetrated by a component or an element. The neutron capture therapy system of the present application includes an accelerator, a beam transport unit, and a neutron beam generating unit. The accelerator accelerates charged particles to generate a charged particle beam. The beam transport unit transports the charged particle beam generated by the accelerator to the neutron beam generating unit. The neutron beam generating unit generates a therapeutic neutron beam. The neutron capture therapy system further includes a shielding wall that accommodates the accelerator, the beam transport unit, and the neutron beam generating unit. A shielding body is provided at a position where the shielding wall is penetrated by the beam transport unit or the neutron beam generating unit on a side of the shielding wall upstream of a beam transport direction. The shielding body is movable and has a first position and a second position. In the first position, an accommodation hole through which the beam transport unit penetrates is formed. In the second position, the accommodation hole is open.

Description

TECHNICAL FIELD

[0001] The present application relates to a radiation irradiation system, in particular to a neutron capture therapy system. BACKGROUND

[0002] With the development of atomic science, radiotherapy such as cobalt-60, linear accelerator, electron beam, etc. has become one of the main means of cancer treatment. However, traditional photon or electron therapy is limited by the physical conditions of the radiation itself, which not only kills tumor cells but also causes damage to a large number of normal tissues along the beam path; in addition, due to the different sensitivity of tumor cells to radiation, the treatment effect of traditional radiotherapy for malignant tumors with high radiation resistance (such as glioblastoma multiforme and melanoma) is often poor.

[0003] In order to reduce the radiation damage to normal tissues around the tumor, the concept of targeted therapy in chemotherapy is applied to radiotherapy; and for tumor cells with high radiation resistance, radiation sources with high relative biological effectiveness (RBE) are actively developed, such as proton therapy, heavy particle therapy, neutron capture therapy, etc. Among them, neutron capture therapy combines the above two concepts, such as boron neutron capture therapy, which provides a better choice for cancer treatment than traditional radiotherapy by specific accumulation of boron-containing drugs in tumor cells and precise neutron beam regulation.

[0004] Various types of radiation are generated during radiotherapy, such as low-energy to high-energy neutrons and photons generated during boron neutron capture therapy, which can cause varying degrees of damage to normal human tissues. Therefore, in the field of radiotherapy, how to achieve effective treatment while reducing radiation pollution to the external environment, medical staff or normal tissues of patients is an extremely important issue.

[0005] Therefore, it is necessary to propose a new technical solution to solve the above problems. SUMMARY

[0006] To solve the above problems, the present application provides a neutron capture therapy system, comprising an accelerator, a beam transmission part, and a neutron beam generating part, the accelerator accelerates charged particles to generate a charged particle beam, the beam transmission part transmits the charged particle beam generated by the accelerator to the neutron beam generating part, and the neutron beam generating part generates a therapeutic neutron beam, the neutron capture therapy system further comprises a shielding wall accommodating the accelerator, the beam transmission part, and the neutron beam generating part, a shielding body is arranged at a position where the shielding wall is penetrated by the beam transmission part or the neutron beam generating part in a direction upstream of the beam transmission direction, the shielding body is movable and has a first position and a second position, in the first position, an accommodation hole through which the beam transmission part passes is formed, and in the second position, the accommodation hole is open. The arrangement of the shielding body can avoid or reduce the leakage of neutrons and other radiation at the position where the shielding wall is penetrated by the components or elements, and the shielding body is movable and has a position where the accommodation hole is open, which can facilitate movement and provide operation space without interfering with the non-movable components of the beam transmission part.

[0007] Preferably, the neutron capture therapy system further comprises a charged particle beam generating chamber and an irradiation chamber, the charged particle beam generating chamber accommodates the accelerator and at least part of the beam transmission part, and the patient receives neutron beam irradiation treatment in the irradiation chamber, the shielding wall comprises a partition wall of the irradiation chamber and the charged particle beam generating chamber, at least part of the neutron beam generating part is embedded in the partition wall, in the first position, the end of the neutron beam generating part towards the accelerator is covered, the backscattered neutrons are shielded, the high neutron dose area is limited, the accelerator components are protected, the irradiation damage of the components is reduced, the element activation of the accelerator components is reduced, and at the same time, when one irradiation chamber is operating, the other irradiation chamber is protected to ensure that the radiation dose of the non-operating irradiation chamber is at a safe level; in the second position, at least part of the end of the neutron beam generating part towards the accelerator is exposed, an operation space is provided, and the neutron beam generating part, such as the target material or the beam shaping body, the cooling pipe described below, can be replaced when the accelerator is turned off, and space can be left for the removed part of the beam transmission part, or the beam transmission part passing through the partition wall and the shielding body can be installed, debugged, and repaired.

[0008] Further, the beam transmission part comprises a first transmission part connected to the accelerator, a beam direction switcher switching the traveling direction of the charged particle beam, and a second transmission part transmitting the charged particle beam to the neutron beam generating part, the second transmission part passes through the first shielding body to reach the neutron beam generating part, and the accommodation hole accommodates the second transmission part.

[0009] Further, the partition wall is provided with a containing groove near one side of the irradiation chamber, which contains the neutron beam generating part and a support module for supporting the neutron beam generating part. The support structure is modularized, so that the neutron beam generating part can be adjusted locally to meet the accuracy requirement and improve the beam quality. A groove is provided near one side of the charged particle beam generating chamber for the beam transmission part to pass through. The containing groove and the groove pass through the partition wall in the neutron line transmission direction. In a plane perpendicular to the neutron line transmission direction, the cross-sectional profile of the neutron beam generating part and its support module is located between the cross-sectional profiles of the containing groove and the groove, so as to avoid the appearance of a through slit in the beam transmission direction, further reduce radiation, and facilitate the adjustment of the support module.

[0010] As another preferred embodiment, the shielding body comprises a first shielding part and a second shielding part, which are respectively moved to the first position along a first direction and a second direction close to the neutron beam generating part. The first shielding part and the second shielding part respectively have a first groove and a second groove, which jointly form the containing hole in the first position.

[0011] Further, the first shielding part and the second shielding part slide along a guide rail, which is fixed on one side of the shielding wall upstream of the beam transmission direction and extends parallel to the ground.

[0012] Further, the material of the first shielding part and the second shielding part comprises a neutron shielding material, which is PE containing boron or heavy spar concrete or lead.

[0013] As another preferred embodiment, the neutron capture therapy system further comprises a treatment table. The neutron beam generating part comprises a target material, a beam shaping body and a collimator. The target material is arranged between the beam transmission part and the beam shaping body. The charged particle beam generated by the accelerator is irradiated to the target material through the beam transmission part and interacts with the target material to generate neutrons. The generated neutrons pass through the beam shaping body and the collimator in turn to form a therapeutic neutron beam and irradiate a patient on the treatment table.

[0014] Further, the beam shaping body comprises a reflector, a moderator, a thermal neutron absorber, a radiation shield, and a beam exit, the moderator moderates the neutrons generated from the target to the epithermal neutron energy region, the reflector surrounds the moderator and guides the deviated neutrons back to the moderator to increase the intensity of the epithermal neutron beam, the thermal neutron absorber is used to absorb thermal neutrons to avoid excessive dose to the normal tissue in the shallow layer during treatment, the radiation shield is used to shield the leaked neutrons and photons to reduce the dose to the normal tissue in the non-irradiated region, the collimator is arranged behind the beam exit to converge the neutron beam, and a radiation shielding device is arranged between the patient and the beam exit to shield the radiation of the beam from the beam exit to the normal tissue of the patient.

[0015] Further, the beam transmission part has a transmission tube for accelerating or transmitting the charged particle beam, the transmission tube extends into the beam shaping body along the direction of the charged particle beam, and sequentially passes through the reflector and the moderator, the target is arranged in the moderator and located at the end of the transmission tube, a cooling tube is arranged between the transmission tube and the reflector and the moderator, the cooling tube is used to connect with an external cooling source and cool the target, and the accommodating hole accommodates the cooling tube.

[0016] The neutron capture therapy system of the present application can avoid or reduce the leakage of neutrons and other radiation at the place where the shielding wall is penetrated by the components or elements, the shielding body is movable and has a position where the accommodating hole is opened, which can facilitate the movement to provide operation space without interfering with the non-movable components of the beam transmission part. BRIEF DESCRIPTION OF DRAWINGS

[0017] Figure 1 It is a structural schematic diagram of the neutron capture therapy system in the embodiment of the present application;

[0018] Figure 2 It is a structural schematic diagram of the target of the neutron capture therapy system in the embodiment of the present application;

[0019] Figure 3 It is a layout schematic diagram of the neutron capture therapy system in the embodiment of the present application in the XY plane;

[0020] Figure 4 It is Figure 3 It is a schematic diagram in the A-A section;

[0021] Figure 5 It is an installation schematic diagram of the beam shaping body support module of the neutron capture therapy system in the embodiment of the present application;

[0022] Figure 6 It is a structural schematic diagram of the shielding body arranged at the position where the neutron beam generating part penetrates the shielding wall of the neutron capture therapy system in the embodiment of the present application;

[0023] Figure 7 for Figure 6 A schematic diagram of another state of the shielding body. Detailed Implementation

[0024] The embodiments of the present invention will be further described in detail below with reference to the accompanying drawings, so that those skilled in the art can implement them based on the description. An XYZ coordinate system is established, with the direction of the charged particle beam P emitted by the accelerator (described later) as the X-axis, the direction orthogonal to the direction of the charged particle beam P emitted by the accelerator as the Y-axis, and the direction perpendicular to the ground as the Z-axis (see reference). Figure 3 and Figure 4 ), and use X, Y, Z in the description of the positional relationship of each constituent element.

[0025] See Figure 1 In this embodiment, the neutron capture therapy system is preferably a boron neutron capture therapy system 100, which is a device for cancer treatment using boron neutron capture therapy. Boron neutron capture therapy treats cancer by irradiating a patient 200 injected with boron (B-10) with a neutron beam N. After the patient 200 takes or injects a boron-containing (B-10) drug, the boron-containing drug selectively accumulates in tumor cells M. Then, utilizing the high capture cross-section of the boron-containing (B-10) drug for thermal neutrons, the neutron capture therapy system... 10 B(n,α) 7 Li neutron capture and nuclear fission reaction produce 4 He and 7 Li has two heavily charged particles. The average energy of these two charged particles is approximately 2.33 MeV, exhibiting high linear energy transfer (LET) and a short range. The linear energy transfer and range of the alpha particle are 150 keV / μm and 8 μm, respectively. 7 Li heavy particles have a range of 175 keV / μm and 5 μm. The total range of the two particles is about the size of a cell. Therefore, the radiation damage to organisms can be limited to the cellular level, which can achieve the purpose of killing tumor cells locally without causing too much damage to normal tissues.

[0026] The boron neutron capture therapy system 100 includes an accelerator 10, a beam transmission unit 20, a neutron beam generation unit 30, and a treatment table 40. The accelerator 10 accelerates charged particles (such as protons, deuterons, etc.) to produce a charged particle beam P, such as a proton beam; the beam transmission unit 20 transmits the charged particle beam P produced by the accelerator 10 to the neutron beam generation unit 30; the neutron beam generation unit 30 produces a therapeutic neutron beam N and irradiates the patient 200 on the treatment table 40.

[0027] The neutron beam generating portion 30 includes a target material T, a beam shaping body 31, a collimator 32, and the charged particle beam P generated by the accelerator 10 is irradiated to the target material T via the beam transport portion 20 and interacts with the target material T to generate neutrons, the generated neutrons pass through the beam shaping body 31 and the collimator 32 in sequence to form a therapeutic neutron beam N and irradiate the patient 200 on the treatment table 40. The target material T is preferably a metal target material. Suitable nuclear reactions are selected according to the required neutron yield and energy, the available accelerated charged particle energy and current size, and the physicochemical properties of the metal target material. The commonly discussed nuclear reactions are 7 Li(p,n) 7 Be and 9 Be(p,n) 9 B, both of which are endothermic reactions. The energy thresholds of the two nuclear reactions are 1.881 MeV and 2.055 MeV, respectively. Since the ideal neutron source for boron neutron capture therapy is superthermal neutrons in the keV energy range, theoretically, if protons with energy slightly higher than the threshold energy are used to bombard a lithium metal target, relatively low-energy neutrons can be generated, which do not need too much moderation and can be used in clinical practice. However, the interaction cross section of lithium metal (Li) and beryllium metal (Be) with protons at the threshold energy is not high. In order to generate a large enough neutron flux, protons with higher energy are usually selected to induce nuclear reactions. The ideal target material should have high neutron yield, neutron energy distribution close to the superthermal neutron energy range (to be described in detail below), little strong penetrating radiation, safety, convenience, easy operation, and high temperature resistance, but in reality, it is difficult to find a nuclear reaction that meets all the requirements. As is well known to those skilled in the art, the target material T can also be made of metal materials other than Li and Be, such as Ta or W and their alloys.

[0028] The beam shaping body 31 can adjust the beam quality of the neutron beam N generated by the interaction of the charged particle beam P with the target material T, and the collimator 32 is used to converge the neutron beam N to have high targeting during treatment. The beam shaping body 31 further includes a reflector 311, a moderator 312, a thermal neutron absorber 313, a radiation shielding body 314, and a beam exit 315. Since the energy spectrum of the neutrons generated by the interaction of the charged particle beam P with the target material T is very wide, in addition to the superthermal neutrons that meet the treatment needs, it is necessary to reduce the content of other types of neutrons and photons as much as possible to avoid harm to the operators or patients. Therefore, the neutrons coming out of the target material T need to pass through the moderator 312 to adjust the fast neutron energy (> 40 keV) to the superthermal neutron energy range (0.5 eV-40 keV) and reduce the thermal neutrons (<0.5 eV) as much as possible. The moderator 312 is made of a material with a large fast neutron interaction cross section and a small superthermal neutron interaction cross section. In this embodiment, the moderator 312 is made of D2O, AlF3, Fluental TMThe reflector 311 surrounds the moderator 312 and reflects neutrons diffused to the surroundings through the moderator 312 back to the neutron beam N to improve the utilization of neutrons, and is made of a material having a strong neutron reflecting capability, in this embodiment, the reflector 311 is made of at least one of Pb or Ni. The moderator 312 has a thermal neutron absorber 313 at the rear thereof, which is made of a material having a large cross section for interaction with thermal neutrons, in this embodiment, the thermal neutron absorber 313 is made of Li-6, and is used to absorb thermal neutrons passing through the moderator 312 to reduce the content of thermal neutrons in the neutron beam N, so as to avoid causing excessive dose to the shallow normal tissue during treatment. It can be understood that the thermal neutron absorber can also be integrated with the moderator, and the material of the moderator contains Li-6. The radiation shielding body 314 is used to shield the neutrons and photons leaking from the part other than the beam outlet 315, and the material of the radiation shielding body 314 includes at least one of a photon shielding material and a neutron shielding material, in this embodiment, the material of the radiation shielding body 314 includes the photon shielding material Pb and the neutron shielding material PE. It can be understood that the beam shaping body 31 can also have other configurations as long as the required super-thermal neutron beam for treatment can be obtained, and a radiation detection assembly (not shown in the figure) can also be arranged in the beam shaping body 31 to detect various radiation lines during neutron generation. The collimator 32 is arranged at the rear of the beam outlet 315, and the super-thermal neutron beam from the collimator 32 irradiates the patient 200, and is slowed down to thermal neutrons after passing through the shallow normal tissue to reach the tumor cells M. It can be understood that the collimator 32 can also be cancelled or replaced by other structures, and the neutron beam directly irradiates the patient 200 from the beam outlet 315. In this embodiment, the radiation shielding device 50 is further arranged between the patient 200 and the beam outlet 315 to shield the radiation of the beam from the beam outlet 315 to the normal tissue of the patient, and it can be understood that the radiation shielding device 50 can also not be arranged.

[0029] The target T is arranged between the beam transmission part 20 and the beam shaping body 31, the beam transmission part 20 has a transmission tube C for accelerating or transmitting the charged particle beam P, in this embodiment, the transmission tube C extends into the beam shaping body 31 along the direction of the charged particle beam P, and sequentially passes through the reflector 311 and the moderator 312, and the target T is arranged in the moderator 312 and located at the end of the transmission tube C to obtain better neutron beam quality. It can be understood that the target can have other arrangement modes, and can also be movable relative to the accelerator or the beam shaping body to facilitate target replacement or uniform action of the charged particle beam on the target. In combination with the above description of the accelerator 10, the beam shaping body 31 and the collimator 32, the super-thermal neutron beam can be obtained by the accelerator 10, the beam shaping body 31 and the collimator 32. Figure 2The target T includes a heat dissipation layer 301, a base layer 302 and an action layer 303. The action layer 303 is used to generate a neutron beam by the charged particle beam P. The base layer 302 supports the action layer 303. In this embodiment, the material of the action layer 303 is Li or its alloy. The charged particle beam P is a proton beam. The target T further includes an oxidation-resistant layer 304 on one side of the action layer 303 to prevent oxidation of the action layer. The charged particle beam P passes through the oxidation-resistant layer 304, the action layer 303 and the base layer 302 in sequence along the incident direction. The material of the oxidation-resistant layer 304 is not easily corroded by the action layer and can reduce the loss of the incident proton beam and the heat caused by the proton beam. For example, the material of the oxidation-resistant layer 304 includes at least one of Al, Ti and their alloys or stainless steel. The heat dissipation layer 301 is made of a material with good thermal conductivity (for example, at least one of Cu, Fe and Al) or at least partially made of the same material as the base layer or is integrated. The heat dissipation layer can have various configurations, such as a flat plate. In this embodiment, the details are not described. The heat dissipation layer 301 is provided with a cooling inlet IN (not shown in the figure), a cooling outlet OUT (not shown in the figure), and a cooling channel 3011 connecting the cooling inlet IN and the cooling outlet OUT. The cooling medium enters from the cooling inlet IN, passes through the cooling channel 3011 and comes out from the cooling outlet OUT. In this embodiment, the first and second cooling pipes 3012 and 3013 are arranged between the reflector 311 and the retarder 312. One end of the first and second cooling pipes 3012 and 3013 is connected to the cooling inlet IN and the cooling outlet OUT of the target T respectively, and the other end is connected to an external cooling source. It can be understood that the first and second cooling pipes can also be arranged in other ways in the beam shaping body, and can also be cancelled when the target is placed outside the beam shaping body. Figure 3 and Figure 4, the boron neutron capture therapy system 100 is configured in the space of two floors L1 and L2, the boron neutron capture therapy system 100 further comprises irradiation rooms 101 (101A, 101B, 101C) and a charged particle beam generation room 102, the patient 200 on the treatment table 40 is treated by neutron beam N irradiation in the irradiation room 101 (101A, 101B, 101C), and the charged particle beam generation room 102 accommodates the accelerator 10 and at least part of the beam transmission part 20. The neutron beam generation part 30 can be one or more to generate one or more therapeutic neutron beams N, and the beam transmission part 20 selectively transmits the charged particle beam P to one or several neutron beam generation parts 30 or simultaneously transmits the charged particle beam P to multiple neutron beam generation parts 30, and each neutron beam generation part 30 corresponds to an irradiation room 101. In this embodiment, there are three neutron beam generation parts and irradiation rooms respectively, which are neutron beam generation parts 30A, 30B, 30C and irradiation rooms 101A, 101B, 101C. The beam transmission part 20 comprises: a first transmission part 21 connected with the accelerator 10; first and second beam direction switches 22, 23 for switching the traveling direction of the charged particle beam P; a second transmission part 24 connected with the first and second beam direction switches 22, 23; third, fourth and fifth transmission parts 25A, 25B, 25C for respectively transmitting the charged particle beam P from the first beam direction switch 22 or the second beam direction switch 23 to the neutron beam generation parts 30A, 30B, 30C, and the generated neutron beams N are respectively irradiated into the patients in the irradiation rooms 101A, 101B, 101C. The third transmission part 25A is connected with the first beam direction switch 22 and the neutron beam generation part 30A, the fourth transmission part 25B is connected with the second beam direction switch 23 and the neutron beam generation part 30B, and the fifth transmission part 25C is connected with the second beam direction switch 23 and the neutron beam generation part 30C. That is, the first transmission part 21 branches into the second transmission part 24 and the third transmission part 25A in the first beam direction switch 22, and the second transmission part 24 branches into the fourth transmission part 25B and the fifth transmission part 25C in the second beam direction switch 23. The first and second transmission parts 21, 24 transmit along the X-axis direction, the third transmission part 25A transmits along the Z-axis direction, and the fourth and fifth transmission parts 25B, 25C transmit in the XY plane and form a "Y" shape with the transmission directions of the first and second transmission parts 21, 24. The neutron beam generation parts 30A, 30B, 30C and the corresponding irradiation rooms 101A, 101B, 101C are respectively arranged along the transmission directions of the third, fourth and fifth transmission parts 25A, 25B, 25C, and the directions of the generated neutron beams N are the same as the transmission directions of the third, fourth and fifth transmission parts 25A, 25B, 25C, so that the directions of the neutron beams generated by the neutron beam generation parts 30B, 30C are in the same plane, and the direction of the neutron beam generated by the neutron beam generation part 30A is perpendicular to the plane.With such an arrangement, space can be effectively utilized while treating multiple patients without excessively lengthening the beam transport line, with less loss. It will be appreciated that the direction of the neutron beam N generated by the neutron beam generating portion 30A (30B, 30C) can also be different from the transport direction of the third (fourth, fifth) transport portion 25A (25B, 25C); the transport directions of the first and second transport portions 21, 24 can also be different, and the second transport portion 24 can also be omitted, with only one beam direction switcher branching the beam into two or more transport portions; the "Y" shape formed by the transport directions of the fourth and fifth transport portions 25B, 25C and the transport direction of the first transport portion 21 can also be a variation of the "Y", for example, the transport direction of the fourth transport portion 25B or the fifth transport portion 25C can be the same as the transport direction of the first transport portion 21, or the transport directions of the fourth and fifth transport portions 25B, 25C and the transport direction of the first transport portion 21 can also be other shapes, such as a "T" shape or an arrowhead shape, as long as the transport directions of the fourth and fifth transport portions 25B, 25C form an included angle greater than 0 degrees in the XY plane; the transport directions of the fourth and fifth transport portions 25B, 25C are not limited to the XY plane, and the transport direction of the third transport portion 25A can also not be along the Z axis, as long as two of the transport directions of the fourth transport portion 25B, the fifth transport portion 25C, and the first transport portion 21 are in the same plane (first plane), the transport direction of the first transport portion 21 and the transport direction of the third transport portion 25A are also in the same plane (second plane), and the first plane and the second plane are different; the third transport portion 25A, the neutron beam generating portion 30A, and the irradiation chamber 101A can also be omitted, so that there is only beam transport in the XY plane.

[0030] The first and second beam direction switches 22, 23 include a deflection electromagnet that deflects the direction of the charged particle beam P and a switch electromagnet that controls the direction of travel of the charged particle beam P, and the boron neutron capture therapy system 100 can also include a beam collector (not shown) for output confirmation of the charged particle beam P before treatment, etc., and the first or second beam direction switch 22, 23 can cause the charged particle beam P to deviate from the normal orbit and be directed to the beam collector.

[0031] The first transfer unit 21, the second transfer unit 24, and the third, fourth, and fifth transfer units 25A, 25B, and 25C are each configured by a transfer tube C and can be formed by connecting a plurality of sub-transfer units, the transfer directions of which can be the same or different. The transfer directions of the first, second, third, fourth, and fifth transfer units 21, 24, 25A, 25B, and 25C can be the transfer direction of any of the sub-transfer units. The first and second planes described above are planes formed between the sub-transfer units directly connected to the beam direction switch. Each of the first, second, third, fourth, and fifth transfer units 21, 24, 25A, 25B, and 25C can include a beam adjustment unit (not shown) for the charged particle beam P. The beam adjustment unit includes a horizontal deflector for adjusting the axis of the charged particle beam P, a horizontal-vertical deflector, a quadrupole electromagnet for suppressing the divergence of the charged particle beam P, and a four-way cutter for shaping the charged particle beam P. The third, fourth, and fifth transfer units 25A, 25B, and 25C can include a current monitor (not shown) and a charged particle beam scanning unit (not shown) as needed. The current monitor measures the current value (i.e., the charge, the irradiation dose rate) of the charged particle beam P irradiated on the target T in real time. The charged particle beam scanning unit scans the charged particle beam P and controls the irradiation of the charged particle beam P with respect to the target T, such as controlling the irradiation position of the charged particle beam P with respect to the target T.

[0032] The charged particle beam generating chamber 102 can include an accelerator chamber 1021 and a beam transport chamber 1022, the accelerator chamber 1021 is two layers, the accelerator 10 extends from L2 to L1. The beam transport chamber 1022 is located at L2, the first transport part 21 extends from the accelerator chamber 1021 to the beam transport chamber 1022. The irradiation chambers 101B, 101C are located at L2, and the irradiation chamber 101A is located at L1. In this embodiment, L1 is below L2, that is, the floor of L2 is the ceiling of L1, and it can be understood that the opposite configuration can also be used. The material of the floor (ceiling) S can be concrete or boron-containing heavy spar concrete with a thickness of 0.5m or more. The irradiation chambers 101A, 101B, 101C and the beam transport chamber 1022 have a shielding space surrounded by a shielding wall W1, which can be a boron-containing heavy spar concrete wall with a thickness of 1m or more and a density of 3g / c.c., including a first partition shielding wall W2 separating the beam transport chamber 1022 from the irradiation chambers 101B, 101C, a second partition shielding wall W3 separating the accelerator chamber 1021 and the beam transport chamber 1022 at L1, a third partition shielding wall W4 separating the accelerator chamber 1021 and the irradiation chamber 101A at L2. The accelerator chamber 1021 is surrounded by a concrete wall W with a thickness of 1m or more and the second partition shielding wall W3 and the third partition shielding wall W4. At least part of the neutron beam generating part 30B, 30C is embedded in the first partition shielding wall W2, and the fourth and fifth transport parts 25B, 25C extend from the beam transport chamber 1022 to the neutron beam generating part 30B, 30C; the neutron beam generating part 30A is located in the irradiation chamber 101A, and the third transport part 25A extends from the beam transport chamber 1022 through the floor S to the irradiation chamber 101A. The irradiation chambers 101A, 101B, 101C have shielding doors D1, D2, D3 for the treatment table 40 and the doctor to enter and exit, respectively, and the accelerator chamber 1021 has shielding doors D4, D5 at L1 and L2, respectively, for the accelerator 1021 chamber to maintain the accelerator 10, the beam transport chamber 1022 has a shielding door D6 for the beam transport part 20 to maintain the beam transport chamber 1022 from the accelerator chamber 1021, and the shielding door D6 is arranged on the second partition shielding wall W3. The inner shielding wall W5 is also provided in the irradiation chambers 101A, 101B, 101C to form a labyrinth-type passage from the shielding doors D1, D2, D3 to the beam exit, to prevent direct irradiation of radiation when the shielding doors D1, D2, D3 are accidentally opened, and the inner shielding wall W5 can be arranged at different positions according to the different layouts of the irradiation chambers, and a shielding door D7 inside the irradiation chamber can be arranged between the inner shielding wall W5 and the shielding wall W1 or the third partition shielding wall W4 to form a secondary protection when the neutron beam irradiation treatment is performed.The inner shielding wall W5 can be a boron-containing barite concrete wall having a thickness of 0.5 m or more and a density of 3 g / c.c. The shielding doors D1, D2, D3, D4, D5, D6, and D7 can be composed of two separate primary shielding doors D and secondary shielding doors D', or only the primary shielding doors D or the secondary shielding doors D', which can be determined according to the actual situation. The primary shielding doors D can be boron-containing PE or barite concrete or lead having a thickness of 0.5 m or more and a density of 6 g / c.c. of the same material, and the secondary shielding doors D' can be boron-containing PE or barite concrete or lead having a thickness of 0.2 m or more and a density of 6 g / c.c. of the same material. In this embodiment, the shielding doors D1, D4, D5, and D6 are composed of the primary shielding doors D and the secondary shielding doors D', the shielding doors D1, D2, and D3 only include the primary shielding doors D, and the shielding door D7 only includes the secondary shielding doors D'. The shielding walls and the shielding doors form a shielding space to inhibit the invasion of the radioactive rays from the outside of the irradiation chambers 101A, 101B, and 101C and the beam transmission chamber 1022 into the inside and the phenomenon of the radioactive rays radiated from the inside to the outside. In this embodiment, the second partition shielding wall W3 separating the accelerator chamber 1021 and the beam transmission chamber 1022 is arranged between the accelerator 10 and the first beam direction switch 22, i.e., the first transmission part 21 passes through the second partition shielding wall W3. It can be understood that the second partition shielding wall W3 and the shielding door D6 can be cancelled or arranged at other positions, such as between the first and second beam direction switches 22 and 23 or between the second beam direction switch 23 and the neutron beam generating parts 30B and 30C; or an additional partition shielding wall and shielding door are arranged between the second partition shielding wall W3 and the first partition shielding wall W2. That is, a shielding wall is arranged between the neutron beam generating part and the accelerator, so that the operator is free from the irradiation of the neutrons and other radioactive rays leaked from the neutron beam generating part during the maintenance and repair of the accelerator, and the reaction of the activation of the accelerator by the neutrons is reduced.

[0033] In combination Figure 5The beam shaping body 31 is supported by a support module 60 arranged in the partition wall 103 (the first partition wall W2). The partition wall 103 is provided with a receiving groove 1031 for at least partially receiving the support module 60 on the side close to the irradiation chamber 101, and a groove 1032 for allowing a transmission tube of the accelerator to pass through on the side close to the charged particle beam generating chamber 102, so that the receiving groove 1031 and the groove 1032 are continuous through the partition wall in the neutron beam N transmission direction. In the present embodiment, the wall surface of the partition wall 103 is a plane, and the neutron beam N transmission direction is perpendicular to the wall surface of the partition wall 103. The support structure is modularized, so that the beam shaping body can be adjusted locally, the accuracy requirement is met, the beam quality is improved, and the assembly tolerance of the target is met. In a plane perpendicular to the neutron beam N transmission direction, the cross-sectional profile of the support module 60 is located between the cross-sectional profiles of the receiving groove 1031 and the groove 1032, so that a through gap is avoided in the beam transmission direction, further reducing radiation, and facilitating adjustment of the support module 60. In the present embodiment, the support module 60 is a cuboid as a whole, and the receiving groove 1031 and the groove 1032 are both "L" shaped in the cross section perpendicular to the neutron beam N transmission direction. The side walls of the receiving groove 1031 and the groove 1032 are parallel to the neutron beam N transmission direction. The partition wall 103 is also provided with a shielding plate 1033 on the side close to the irradiation chamber 102. The shielding plate 1033 can enhance the shielding effect of the partition wall, suppress the secondary radiation generated by the partition wall, and thus avoid radiation to the normal tissue of the patient. In a plane perpendicular to the neutron beam N transmission direction, the shielding plate 1033 can match the cross-sectional profile of the support module 60, so as to shield the neutrons leaked from between the support module and the partition wall. The shielding plate is a PE plate. It can be understood that the side of the partition wall 103 close to the charged particle beam generating chamber 102 and the side of the support module 60 close to the irradiation chamber 101 can also be provided with a shielding plate. The shielding plate can be made of lead or other neutron or photon shielding materials, and can also not be provided with a shielding plate.

[0034] The outgoing direction of the neutrons generated by the interaction of the charged particle beam P with the target material T is almost uniformly distributed in space. At the same time, a large number of recoil neutrons are generated during the "shaping" of the neutrons by the beam shaper 31. This part of the recoil neutrons needs to be considered in the design of the radiation shielding. The shielding wall or floor cannot be closed at the places where the components or elements pass through, which is easy to cause leakage of neutrons and other radiation lines. In the present embodiment, the neutron beam generation part 30B, 30C passes through the first partition shielding wall W2, the first transmission part 21 passes through the second partition shielding wall W3, and the third transmission part 25A passes through the floor S. The side of the first partition shielding wall W2, the second partition shielding wall W3, and the floor S upstream of the beam transmission direction can be provided with the first shielding body 70, the second shielding body 80, and the third shielding body 90, respectively, which pass through the parts of the neutron beam generation part 30B, 30C, the first transmission part 21, and the third transmission part 25A. The first shielding body 70 covers the end of the neutron beam generation part 30B, 30C towards the accelerator, preventing the neutrons overflowing or reflecting from the beam shaper of the neutron beam generation part 30B, 30C from entering the accelerator chamber 1021 and the beam transmission chamber 1022. The fourth and fifth transmission parts 25B, 25C pass through the first shielding body 70 to reach the target material T of the neutron beam generation part 30B, 30C. The second shielding body 80 prevents the neutrons overflowing or reflecting from the beam transmission part 20 from entering the accelerator chamber 1021. The first transmission part 21 passes through the second shielding body 80 and the second partition shielding wall W3 to reach the first beam direction switch 22. The third shielding body 90 prevents the neutrons overflowing or reflecting from the irradiation chamber 101A from entering the beam transmission chamber 1022. The third transmission part 25A passes through the third shielding body 90 and the floor S to reach the neutron beam generation part 30A. The materials of the first shielding body 70, the second shielding body 80, and the third shielding body 90 can be PE containing boron or barite concrete or lead, and can also include other neutron shielding materials.

[0035] The first, second and third shielding bodies 70, 80, 90 are described in detail below by taking the first shielding body 70 as an example. In this embodiment, the first shielding body 70 is movable and has a first position and a second position. In the first position, the first shielding body 70 forms an accommodation hole 71 through which the fourth and fifth beam transport sections 25B, 25C pass and covers the end of the neutron beam generating sections 30B, 30C facing the accelerator 10, shielding the backstreaming neutrons, limiting the high neutron dose area, protecting the accelerator components, reducing the irradiation damage of the components, reducing the element activation of the accelerator components, and at the same time, protecting the other irradiation chamber when one irradiation chamber is in operation, ensuring that the radiation dose of the non-operating irradiation chamber is at a safe level; in the second position, the accommodation hole 71 is opened to expose the end of the neutron beam generating sections 30B, 30C facing the accelerator 10, forming an operation space without removing the transport pipes C passing through the accommodation hole 71, and the neutron beam generating sections 30B, 30C, such as the target material T, the beam shaping body 31, the radiation detection assembly arranged in the beam shaping body 31, or the first and second cooling pipes 3012, 3013, can be replaced when the accelerator 10 is turned off. The space can also be left for the removed part of the transport pipe, or the first and second cooling pipes 3012, 3013 or other functional components can be installed, debugged, and repaired. The accommodation hole can accommodate the transport pipes C, magnets, etc. of the fourth and fifth beam transport sections 25B, 25C, and can also accommodate the first and second cooling pipes 3012, 3013 or other functional components, which can facilitate movement and provide an operation space without interfering with the non-movable components of the beam transport section. The first shielding body 70 and the first partitioning shielding wall W2 can be in close contact to enhance the shielding effect, or can have a gap, and the shielding effect can be achieved by adjusting the size of the first shielding body 70.

[0036] As shown in Figure 6 and Figure 7 , the first shielding body 70 includes a first shielding section 72 and a second shielding section 73, the first shielding section 72 and the second shielding section 73 respectively move to the first position along the first and second directions L1, L2 close to the neutron beam generating sections 30B, 30C, the first shielding section 72 and the second shielding section 73 respectively have first and second grooves 721, 731, the first and second grooves 721, 731 jointly form the accommodation hole 71 through which the fourth and fifth beam transport sections 25B, 25C pass and cover the end of the neutron beam generating sections 30B, 30C facing the accelerator 10 in the first position; the first shielding section 72 and the second shielding section 73 respectively move to the second position along the third and fourth directions L3, L4 away from the neutron beam generating sections 30B, 30C, and in the second position, the accommodation hole 71 is opened to expose the end of the neutron beam generating sections 30B, 30C facing the accelerator 10, forming an operation space without removing the transport pipes C passing through the accommodation hole 71. It can be understood that the first shielding body 70 can also include a third shielding section or be composed of more than three shielding sections.

[0037] In the embodiment, the first shielding part 72 and the second shielding part 73 slide along the guide rail 74, the guide rail 74 and the rollers 75 fixed on the first and second shielding parts 72, 73 constitute a sliding assembly of the first shielding body 70, the first and second shielding parts 72, 73 are configured as a double sliding door, the guide rail 74 is fixed on the side of the first partition shielding wall W2 facing the charged particle beam generating chamber 102 and extends in a direction parallel to the ground (XY plane), and it can be understood that the first and second shielding parts 72, 73 and the sliding assembly can have other settings and can also be moved by other means, such as rotation, etc.

[0038] The first and second beam direction switchers 22, 23 are respectively surrounded by shielding covers 26 to prevent neutrons and other radiation from leaking from the beam direction switchers, and the shielding covers 26 can be made of PE containing boron or barite concrete or lead. It can be understood that the first and second beam direction switchers 22, 23 can also be entirely surrounded by one shielding cover 26; other parts of the beam transmission part, such as the vacuum tube, can also be surrounded by a shielding cover to prevent neutrons and other radiation from leaking from the beam transmission part.

[0039] The boron neutron capture therapy system 100 can also include a preparation room, a control room and other spaces for assisting treatment, and each irradiation room can be configured with a preparation room for preparing the patient to be fixed to the treatment table, injecting boron medicine, simulating treatment planning and other preparations before irradiation treatment. A connecting passage is provided between the preparation room and the irradiation room, and after the preparation work is completed, the patient is directly pushed into the irradiation room or automatically enters the irradiation room by the control mechanism through the track. The preparation room and the connecting passage are also closed by shielding walls, and the preparation room also has a shielding door. The control room is used to control the accelerator, the beam transmission part, the treatment table and the like, and controls and manages the entire irradiation process. The management personnel in the control room can also monitor multiple irradiation rooms at the same time.

[0040] It can be understood that the shielding walls (including the concrete walls W) in the embodiment, the shielding doors, the shielding bodies and the shielding covers can have other thicknesses or densities or be replaced by other materials.

[0041] Although the above describes the specific embodiments of the present application in order to facilitate the understanding of the present application by those skilled in the art, it should be clear that the present application is not limited to the scope of the specific embodiments, and for those skilled in the art, it is obvious that various changes are within the spirit and scope of the present application defined and determined by the appended claims, and these changes are within the scope of the present application claimed.

Claims

1. A neutron capture therapy system, comprising an accelerator, a beam transmission unit, and a neutron beam generation unit, wherein the accelerator accelerates charged particles to generate a charged particle beam, the beam transmission unit transmits the charged particle beam generated by the accelerator to the neutron beam generation unit, and the neutron beam generation unit generates a therapeutic neutron beam, characterized in that... The neutron capture therapy system further includes a charged particle beam generation chamber, an irradiation chamber, and a shielding wall accommodating the accelerator, beam transmission unit, and neutron beam generation unit. The charged particle beam generation chamber houses the accelerator and at least a portion of the beam transmission unit. The patient undergoes neutron beam irradiation treatment in the irradiation chamber. The shielding wall includes a partition wall between the irradiation chamber and the charged particle beam generation chamber. At least a portion of the neutron beam generation unit is embedded in the partition wall. A shielding wall is installed on the upstream side of the partition wall facing the beam transmission direction, at a location through which the beam transmission unit or the neutron beam generation unit passes. The shield is movable and has a first position and a second position. In the first position, a receiving hole is formed through which the beam transmission part passes. In the second position, the receiving hole is open. The partition wall near the irradiation chamber is provided with a receiving groove that at least partially accommodates the neutron beam generating part and a support module for supporting the neutron beam generating part. The neutron beam generating part includes a target material and a beam shaper. The support module is disposed in the partition wall. The support structure is modular, and the beam shaper is supported by the support module so that the position of the beam shaper is adjustable.

2. The neutron capture therapy system as described in claim 1, characterized in that, In the first position, the shield covers the end of the neutron beam generating section facing the accelerator, and in the second position, at least partially exposes the end of the neutron beam generating section facing the accelerator.

3. The neutron capture therapy system as described in claim 2, characterized in that, The beam transmission section includes a first transmission section connected to the accelerator, a beam direction switcher for switching the direction of travel of the charged particle beam, and a second transmission section for transmitting the charged particle beam to the neutron beam generating section. The second transmission section passes through the shield to reach the neutron beam generating section, and the receiving hole accommodates the second transmission section.

4. The neutron capture therapy system as described in claim 2, characterized in that, The partition wall is provided with a groove on the side near the charged particle beam generation chamber for the beam transmission section to pass through. The receiving groove and the slot penetrate the partition wall in the neutron beam transmission direction. On a plane perpendicular to the neutron beam transmission direction, the cross-sectional profile of the neutron beam generation section and its support module is located between the cross-sectional profiles of the receiving groove and the slot.

5. The neutron capture therapy system as described in claim 1, characterized in that, The shielding body includes a first shielding part and a second shielding part. The first shielding part and the second shielding part move to the first position along a first direction and a second direction close to the neutron beam generating part, respectively. The first shielding part and the second shielding part have a first groove and a second groove, respectively. The first groove and the second groove together form the receiving hole at the first position.

6. The neutron capture therapy system as described in claim 5, characterized in that, The first shielding part and the second shielding part slide along the guide rail, which is fixed on the upstream side of the shielding wall facing the beam transmission direction and extends parallel to the ground.

7. The neutron capture therapy system as described in claim 5, characterized in that, The materials of the first shielding part and the second shielding part include neutron shielding materials, and the materials of the first shielding part and the second shielding part are boron-containing PE, barite concrete or lead.

8. The neutron capture therapy system as described in claim 1, characterized in that, The neutron capture therapy system further includes a treatment table, and the neutron beam generation unit further includes a collimator. The target material is disposed between the beam transmission unit and the beam shaping body. The charged particle beam generated by the accelerator irradiates the target material through the beam transmission unit and interacts with the target material to generate neutrons. The generated neutrons pass sequentially through the beam shaping body and the collimator to form a therapeutic neutron beam and irradiate the patient on the treatment table.

9. The neutron capture therapy system as described in claim 8, characterized in that, The beam shaping device includes a reflector, a decelerator, a thermal neutron absorber, a radiation shield, and a beam exit. The decelerator slows down neutrons generated from the target material to the ultrathermal neutron energy region. The reflector surrounds the decelerator and guides deviated neutrons back to the decelerator to increase the intensity of the ultrathermal neutron beam. The thermal neutron absorber absorbs thermal neutrons to avoid excessive doses to superficial normal tissues during treatment. The radiation shield shields leaked neutrons and photons to reduce the dose to normal tissues in non-irradiated areas. The collimator is located behind the beam exit to converge the neutron beam. A radiation shielding device is provided between the patient and the beam exit to shield the patient's normal tissues from radiation from the beam exit.

10. The neutron capture therapy system as described in claim 9, characterized in that, The beam transmission section has a transmission tube for accelerating or transmitting a charged particle beam. The transmission tube extends into the beam shaper along the direction of the charged particle beam and passes through the reflector and the decelerator in sequence. The target material is disposed in the decelerator and located at the end of the transmission tube. A cooling tube is disposed between the transmission tube and the reflector and the decelerator. The cooling tube is used to connect to an external cooling source and cool the target material. The receiving hole accommodates the cooling tube.

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