WO2022228304A1 - Neutron capture therapy system - Google Patents

Abstract

A neutron capture therapy system (100), which can prevent or reduce the leakage of neutrons and other radiation rays caused by places in shielding walls (W1, W2, W3, W4) or floors where components or elements pass through, and the arrangement of a neutron shielding structure can reduce the generation of secondary radiation after a mounting mechanism (70A) or a driving mechanism (70B) is irradiated by neutrons. The neutron capture therapy system (100) comprises an accelerator (10), a beam transmission unit (20), a neutron beam generating unit (30), and shielding walls (W1, W2, W3, W4) which accommodate the accelerator (10), the beam transmission unit (20) and the neutron beam generating unit (30). Shielding bodies (70, 80, 90) are disposed at portions of the shielding walls (W1, W2, W3, W4) where the beam transmission unit (20) or the neutron beam generating unit (30) on the side upstream towards the beam transmission direction passes through. The neutron capture therapy system (100) further comprises a mounting mechanism (70A) or driving mechanism (70B) of the shielding bodies (70, 80, 90), the mounting mechanism (70A) is used for movably mounting the shielding bodies (70, 80, 90) on the side of the shielding walls (W1, W2, W3, W4) upstream towards the beam transmission direction, the driving mechanism (70B) is used for driving the shielding bodies (70, 80, 90) to move, and the mounting mechanism (70A) or the driving mechanism (70B) is provided with the neutron shielding structure.

Description

Neutron Capture Therapy System technical field

The invention relates to a radiation irradiation system, in particular to a neutron capture treatment system.

Background technique

With the development of atomic science, radiation therapy such as cobalt sixty, 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 radiation itself. While killing tumor cells, it will also cause damage to a large number of normal tissues along the beam path. In addition, due to the different sensitivity of tumor cells to radiation, traditional radiation therapy For more radioresistant malignant tumors (eg: glioblastoma multiforme (glioblastoma multiforme), melanoma (melanoma)) treatment results are often poor.

In order to reduce the radiation damage to the normal tissues around the tumor, the concept of targeted therapy in chemotherapy has been applied to radiation therapy; and for tumor cells with high radiation resistance, it is also actively developed with a high relative biological effect (relative biological effect). biological effectiveness, RBE) radiation sources, such as proton therapy, heavy particle therapy, neutron capture therapy, etc. Among them, neutron capture therapy is a combination of the above two concepts, such as boron neutron capture therapy, through the specific accumulation of boron-containing drugs in tumor cells, with precise neutron beam regulation, to provide better than traditional radiation. Cancer treatment options.

Various types of radiation are produced during radiotherapy, such as boron neutron capture therapy, which produces low-energy to high-energy neutrons and photons. These radiations may cause different degrees of damage to normal human tissues. Therefore, in the field of radiation therapy, how to reduce radiation pollution to the external environment, medical personnel or normal tissues of patients while achieving effective treatment is an extremely important topic. Radiation therapy equipment is usually installed in a space surrounded by shielding materials. The shielding wall formed by the shielding material cannot be closed shielding where the components or components pass through, which is easy to cause radiation leakage. Set up a shielding structure to strengthen the shielding effect; the auxiliary parts between the strengthening shielding structure and the shielding wall are usually steel structures. After the steel is irradiated by neutrons, radioactive isotopes with long half-lives, such as cobalt 60, will form secondary radiation, which is harmful to the environment and the environment. Radiation safety has a negative impact.

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

SUMMARY OF THE INVENTION

In order to solve the above problems, one aspect of the present invention provides a neutron capture therapy system, comprising an accelerator, a beam transmission part, and a neutron beam generation part, wherein the accelerator accelerates charged particles to generate a charged particle beam, and the beam The transmission part transmits the charged particle beam generated by the accelerator to the neutron beam generation part, and the neutron beam generation part generates a neutron beam for treatment; A shield wall in the space of the beam transmission unit and the neutron beam generation unit is provided at a portion where the beam transmission unit or the neutron beam generation unit passes through the side of the shield wall facing upstream in the beam transmission direction. The shielding body, the neutron capture therapy system further comprises a mounting mechanism or a driving mechanism of the shielding body, the mounting mechanism is used for movably mounting the shielding body on the upstream side of the shielding wall towards the beam transmission direction On one side, the drive mechanism is used to drive the shield body to move, and the drive mechanism may be manually driven or electrically driven. The shielding body can avoid or reduce the leakage of neutrons and other radiation lines caused by the shielding wall passing through the components or elements. The installation mechanism of the shielding body is provided with a first neutron shielding structure or the driving mechanism is provided with a second neutron shielding structure. The neutron shielding structure reduces the secondary radiation generated after the installation mechanism or the driving mechanism is irradiated by neutrons.

As a preferred option, the installation mechanism includes a first connecting piece that supports the shielding body, and the first neutron shielding structure shields the exposed portion of the first connecting piece.

Further, the installation mechanism includes a guide rail and a roller, the guide rail is fixed on the side of the shielding wall facing the upstream of the beam transmission direction, the roller is fixed on the shield body, and the shield body can pass the roller along the direction. The guide rail slides.

Further, the installation mechanism includes a frame, the shielding body is a plate fixed to the frame, a connecting plate is fixed on the top of the frame, and the roller is fixed to the connecting plate through a first connecting piece. Further, the first connecting piece passes through the connecting plate, the roller is mounted on one end of the first connecting piece, and the first neutron shielding structure covers the part of the other end of the first connecting piece protruding from the connecting plate or covers the first connecting piece at the end of the connecting piece. The part between the roller and the connecting plate or the covering part of the first connecting piece and the connecting plate overlapping and the exposed part or the whole covering the first connecting piece and the connecting plate.

As a preferred option, the driving mechanism includes a fixing bracket and a second connecting piece for carrying the driving mechanism, the fixing bracket is fixedly mounted to the shielding wall through the second connecting piece, and the second neutron shielding structure A baffle shielding the second connecting piece is included. Further, the baffle is fixed on the fixed bracket, and the second connecting piece is shielded on the side facing the upstream of the beam transmission direction, which can be L-shaped or

shape or circumferentially closed.

As a preferred example, the driving mechanism includes an air cylinder, the air cylinder includes a cylinder block, and the second neutron shielding structure includes a collar covering the periphery of the cylinder body.

Further, the cylinder body is fixed to the shielding wall, such as by a fixing bracket; the cylinder further includes a piston, one end of the piston protrudes into the cylinder body, and the other end of the piston is connected to the shielding body , such as fixed connection with the shield through the connecting rod.

Further, the driving mechanism further includes a transmission member connected to the piston, the shielding body includes a first shielding portion and a second shielding portion, the first shielding portion and the second shielding portion are connected between the cylinder and the cylinder. Driven by the transmission member, it moves in the opposite direction.

Further, the transmission member includes a sprocket and chains located on both sides of the sprocket, the chains can move around the sprocket; the chains on both sides of the sprocket are respectively connected to the first shielding portion and the chain. The second shielding part, such as the chains on both sides of the sprocket, are fixedly connected to the first and second frames fixing the first shielding part and the second shielding part respectively, the piston of the cylinder is connected to the first or second frame, and the The first shielding part and the second shielding part move in opposite directions under the driving of the piston and the chain.

As a preferred material, the material of the first and second neutron shielding structures is a boron-containing resin or a boron-containing glass fiber composite material.

Preferably, the materials of the first shielding part and the second shielding part are neutron shielding materials, such as boron-containing PE; the materials of the first and second frames are neutron-irradiated product Materials with radioactivity or products with low activity after being irradiated by neutrons or with short half-lives of radioisotopes produced after being irradiated by neutrons, such as aluminum alloys.

As a preferred material, the first and second connecting members and the cylinder body are made of steel.

The neutron capture therapy system of the present invention can avoid or reduce the leakage of neutrons and other radiation rays caused by the shielding wall where the components or elements pass through. The installation mechanism or driving mechanism of the shielding body includes a neutron shielding structure to avoid Secondary radiation is generated after the mounting mechanism or the driving mechanism is irradiated by neutrons.

Description of drawings

1 is a schematic structural diagram of a neutron capture therapy system in an embodiment of the present invention;

FIG. 2 is a schematic diagram of a target structure of a neutron capture therapy system in an embodiment of the present invention;

3 is a schematic diagram of the layout of the neutron capture therapy system in the XY plane according to the embodiment of the present invention;

Fig. 4 is the schematic diagram of Fig. 3 in A-A section;

5 is a schematic diagram of the installation of the beam shaping body support module of the neutron capture therapy system according to the embodiment of the present invention;

6 is a schematic structural diagram of a shielding body disposed at a position where the neutron beam generating part of the neutron capture therapy system passes through the shielding wall in an embodiment of the present invention;

FIG. 7 is a schematic diagram of another state of the shielding body of FIG. 6;

8 is a schematic structural diagram of a shielding body disposed at a position where the neutron beam generating part of the neutron capture therapy system passes through the shielding wall in another embodiment of the present invention;

FIG. 9 is a partially enlarged schematic view of the mounting mechanism and the driving mechanism of the shield body of FIG. 8 in another state;

Fig. 10 is a partial enlarged schematic view of the installation mechanism of the shield body of Fig. 8;

11a-g are schematic diagrams of the neutron shielding structure of the mounting mechanism and the driving mechanism of the shielding body of FIG. 8 .

Detailed ways

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 the embodiments with reference to the description. XYZ is set with the direction of the charged particle beam P emitted from the accelerator described later as the X axis, the direction perpendicular to the direction of the charged particle beam P emitted from the accelerator as the Y axis, and the direction perpendicular to the ground as the Z axis. A coordinate system (refer to FIGS. 3 and 4 ), and X, Y, and Z are used in the description of the positional relationship of each component.

Referring to FIG. 1 , the neutron capture therapy system in this embodiment is preferably a boron neutron capture therapy system 100 , which is a device for cancer treatment using boron neutron capture therapy. The boron neutron capture therapy performs cancer treatment by irradiating a neutron beam N to a patient 200 injected with boron (B-10), and after the patient 200 takes or injects a drug containing boron (B-10), the drug containing boron selectively aggregates In tumor cells M, ⁴ He and ⁷ Li were generated by ¹⁰ B(n,α) ⁷ Li neutron capture and nuclear fission reaction using boron (B-10)-containing drugs with high capture cross-section for thermal neutrons Two heavily charged particles. The average energy of the two charged particles is about ^2.33MeV , which is characterized by high linear energy transfer (LET) and short range. It is 175keV/μm, 5μm, the total range of the two particles is about the size of a cell, so the radiation damage to the organism can be limited to the cell level, and it can achieve local killing without causing too much damage to normal tissues. The purpose of dead tumor cells.

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 generate a charged particle beam P such as a proton beam; the beam transmission part 20 transmits the charged particle beam P generated by the accelerator 10 to the neutron beam generation part 30; The neutron beam generator 30 generates a neutron beam N for treatment and irradiates the patient 200 on the treatment table 40 .

The neutron beam generating unit 30 includes a target T, a beam shaping body 31 and a collimator 32 . The charged particle beam P generated by the accelerator 10 is irradiated to the target T through the beam transmission unit 20 and interacts with the target T to generate neutrons. , the generated neutrons sequentially pass through the beam shaping body 31 and the collimator 32 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. According to the required neutron yield and energy, the available accelerated charged particle energy and current, and the physical and chemical properties of the metal target, the appropriate nuclear reaction is selected. The nuclear reactions that are often discussed 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 1.881MeV and 2.055MeV, respectively. Since the ideal neutron source for boron neutron capture therapy is epithermal neutrons with keV energy level, theoretically, if proton bombardment with energy only slightly higher than the threshold is used Lithium metal targets can generate relatively low-energy neutrons and can be used clinically without too much retardation. However, the proton interaction cross-sections between lithium metal (Li) and beryllium metal (Be) targets and threshold energy Not high, in order to generate a sufficiently large neutron flux, usually higher energy protons are used to initiate nuclear reactions. The ideal target material should have the characteristics of high neutron yield, neutron energy distribution close to epithermal neutron energy region (described in detail below), no generation of too much strong penetrating radiation, safe, cheap, easy to operate, and high temperature resistance. But in practice it is not possible to find a nuclear reaction that meets all requirements. As known to those skilled in the art, the target T can also be made of metal materials other than Li and Be, for example, Ta or W and alloys thereof. The accelerator 10 may be a linear accelerator, a cyclotron, a synchrotron, or a synchrocyclotron.

The beam shaper 31 can adjust the beam quality of the neutron beam N generated by the action of the charged particle beam P and the target T, and the collimator 32 is used for converging the neutron beam N, so that the neutron beam N is in the process of treatment. Has high targeting. The beam shaping body 31 further includes a reflector 311, a retarder 312, a thermal neutron absorber 313, a radiation shielding body 314 and a beam outlet 315. The neutrons generated by the action of the charged particle beam P and the target T have a very high energy spectrum. In addition to epithermal neutrons to meet the needs of treatment, it is necessary to reduce the content of other types of neutrons and photons as much as possible to avoid harm to operators or patients, so the neutrons from the target T need to pass through the retarder 312 Adjust the fast neutron energy (>40keV) to the epithermal neutron energy region (0.5eV-40keV) and reduce thermal neutrons (<0.5eV) as much as possible, the retarder 312 has a large cross section by interacting with fast neutrons , made of materials with small epithermal neutron action cross section, in this embodiment, the retarder 312 is made of D ₂ O, AlF ₃ , Fluental ^TM , CaF ₂ , Li ₂ CO ₃ , MgF ₂ and Al ₂ O ₃ At least one is made; the reflector 311 surrounds the retarder 312, and reflects the neutrons diffused to the surrounding through the retarder 312 back to the neutron beam N to improve the utilization rate of neutrons. Made of strong material, in this embodiment, the reflector 311 is made of at least one of Pb or Ni; there is a thermal neutron absorber 313 at the rear of the retarder 312, which is made of a thermal neutron with a large cross section. In this embodiment, the thermal neutron absorber 313 is made of Li-6, and the thermal neutron absorber 313 is used to absorb thermal neutrons passing through the retarder 312 to reduce thermal neutrons in the neutron beam N It is understood that the thermal neutron absorber can also be integrated with the retarder, and the material of the retarder contains Li-6; the radiation shield 314 is used for In order to shield the neutrons and photons leaking from outside the beam exit 315, the material of the radiation shielding body 314 includes at least one of photon shielding material and neutron shielding material. In this embodiment, the material of the radiation shielding body 314 includes The photon shielding material lead (Pb) and the neutron shielding material polyethylene (PE). It can be understood that the beam shaper 31 can also have other structures, as long as the epithermal neutron beam required for the treatment can be obtained, and a radiation detection component (not shown in the figure) can also be arranged in the beam shaper 31 to generate neutrons All kinds of radiation in the process are detected. The collimator 32 is arranged at the rear of the beam exit 315, and the epithermal neutron beam from the collimator 32 is irradiated to the patient 200, and after passing through the superficial normal tissue, it is slowed down as thermal neutrons and reaches the tumor cell M, which is understandable. , the collimator 32 can also be eliminated or replaced by other structures, and the neutron beam exits from the beam exit 315 to directly irradiate the patient 200 . In this embodiment, a radiation shielding device 50 is also provided between the patient 200 and the beam exit 315 to shield the radiation from the beam exiting the beam exit 315 to the normal tissue of the patient. It is understood that the radiation shielding device 50 may not be provided. .

The target T is arranged between the beam transmission part 20 and the beam shaping body 31 , and the beam transmission part 20 has a transmission tube C for accelerating or transporting the charged particle beam P. In this embodiment, the transmission tube C moves along the charged particles The beam P extends into the beam shaping body 31, and passes through the reflector 311 and the retarder 312 in turn. The target T is set in the retarder 312 and at the end of the transmission tube C to obtain better neutron radiation. bundle quality. It can be understood that the target material can be set in other ways, and can also be movable relative to the accelerator or the beam shaping body, so as to facilitate target replacement or make the charged particle beam interact with the target material uniformly. 2 , the target T includes a heat dissipation layer 301 , a base layer 302 and an action layer 303 , the action layer 303 interacts with the charged particle beam P to generate a neutron beam, and the base layer 302 supports the action layer 303 . In this embodiment, the material of the active layer 303 is Li or its alloy, the charged particle beam P is a proton beam, and the target T further includes an anti-oxidation layer 304 located on one side of the active layer 303 for preventing the active layer from being oxidized, and the charged particle beam P sequentially passes through the anti-oxidation layer 304 , the active layer 303 and the base layer 302 along the incident direction. The material of the anti-oxidation layer 304 is not easily corroded by the active layer and can reduce the loss of the incident proton beam and the heating caused by the proton beam, such as including at least one of Al, Ti and its alloys or stainless steel. The heat dissipation layer 301 is made of a material with good thermal conductivity (for example, including at least one of Cu, Fe, and Al), or at least partially adopts the same material as the base layer or is integrated. The heat dissipation layer may have various structures, such as a flat plate shape, which will not be described in detail in this embodiment. The cooling layer 301 is provided with a cooling inlet IN (not shown), a cooling outlet OUT (not shown), and a cooling channel 3011 connecting the cooling inlet IN and the cooling outlet OUT. Exit OUT out. In this embodiment, first and second cooling pipes 3012 and 3013 are arranged between the transmission pipe C, the reflector 311 and the retarding body 312 . One ends of the first and second cooling pipes 3012 and 3013 are respectively connected to the cooling inlet of the target T IN and cooling outlet OUT are connected, 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 the beam shaping body in other ways, and can also be eliminated when the target material is placed outside the beam shaping body. 3 and 4 , the boron neutron capture therapy system 100 is integrally configured in the spaces of the two floors L1 and L2. The boron neutron capture therapy system 100 further includes an irradiation chamber 101 (101A, 101B, 101C) and a charged particle beam generator. Room 102, the patient 200 on the treatment table 40 is treated with neutron beam N irradiation in the irradiation room 101 (101A, 101B, 101C), which houses the accelerator 10 and at least part of the beam delivery section 20. There may be one or more neutron beam generating units 30 to generate one or more therapeutic neutron beams N, and the beam transmitting unit 20 may selectively transmit the charged particle beam P to one or more neutron beam generating units 30 Alternatively, the charged particle beams P are simultaneously transmitted to a plurality of neutron beam generating units 30 , and each neutron beam generating unit 30 corresponds to one irradiation chamber 101 . In this embodiment, there are three neutron beam generators and three irradiation chambers, which are neutron beam generators 30A, 30B, and 30C and irradiation chambers 101A, 101B, and 101C, respectively. The beam transmission part 20 includes: a first transmission part 21, which is connected to the accelerator 10; first and second beam direction switches 22 and 23, which switch the traveling direction of the charged particle beam P; and a second transmission part 24, which is connected to the first , the second beam direction switcher 22, 23; the third, fourth, fifth transmission parts 25A, 25B, 25C, respectively, the charged particle beam P is switched from the first beam direction switcher 22 or the second beam direction The generator 23 is transmitted to the neutron beam generators 30A, 30B, and 30C, and the generated neutron beams N are irradiated to the patients in the irradiation chambers 101A, 101B, and 101C, respectively. The third transmission unit 25A is connected to the first beam direction switch 22 and the neutron beam generation unit 30A, the fourth transmission unit 25B is connected to the second beam direction switch 23 and the neutron beam generation unit 30B, and the fifth transmission unit 25C is connected to The second beam direction switch 23 and the neutron beam generator 30C. That is, the first transmission part 21 is branched 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 is branched into the second transmission part 24 in the second beam direction switch 23. The fourth transfer section 25B and the fifth transfer section 25C. The first and second transmission parts 21 and 24 are transmitted in the X-axis direction, the third transmission part 25A is transmitted in the Z-axis direction, and the transmission directions of the fourth and fifth transmission parts 25B and 25C are in the XY plane and are consistent with the first and second transmission parts. The transmission directions of the two transmission parts 21 and 24 are in a "Y" shape, and the neutron beam generating parts 30A, 30B and 30C and the corresponding irradiation chambers 101A, 101B and 101C are along the third, fourth and fifth transmission parts 25A and 25B respectively. The transmission directions of the neutron beams 25C and 25C are set, and the N directions of the generated neutron beams are respectively the same as the transmission directions of the third, fourth, and fifth transmission parts 25A, 25B, and 25C, so that the neutron beams generated by the neutron beam generation parts 30B and 30C The directions are in the same plane, and the direction of the neutron beam generated by the neutron beam generator 30A is perpendicular to the plane. By adopting such an arrangement, the space can be effectively utilized, and multiple patients can be treated at the same time, and the transmission line of the beam is not extended too much, and the loss is small. It can be understood that the N direction of the neutron beam generated by the neutron beam generating part 30A (30B, 30C) and the transmission direction of the third (fourth, fifth) transmission part 25A (25B, 25C) can also be different; The transmission directions of the two transmission parts 21 and 24 can also be different, and the second transmission part 24 can also be eliminated, and only has one beam direction switcher to branch the beam into two or more transmission parts; the fourth and fifth transmission parts The “Y” shape formed by the transmission directions of the transmission parts 25B and 25C and the transmission direction of the first transmission part 21 may also be a deformation of the “Y”, for example, the transmission direction of the fourth transmission part 25B or the fifth transmission part 25C is the same as the transmission direction of the first transmission part 21 . The transmission direction of one transmission part 21 is the same, the transmission direction of the fourth and fifth transmission parts 25B, 25C and the transmission direction of the first transmission part 21 can also be in other shapes, such as "T" shape or arrow shape, as long as the fourth, The transmission directions of the fifth transmission parts 25B and 25C may form an included angle greater than 0 degrees on the XY plane; the transmission directions of the fourth and fifth transmission parts 25B and 25C are not limited to the XY plane, and the transmission direction of the third transmission part 25A is not limited to the XY plane. It may not be along the Z axis, as long as two of the transmission direction of the fourth transmission part 25B, the transmission direction of the fifth transmission part 25C, and the transmission direction of the first transmission part 21 are in the same plane (first plane), the first The transmission direction of the transmission part 21 and the transmission direction of the third transmission part 25A are also in the same plane (second plane), and the first plane and the second plane are different; the third transmission part 25A, the neutron beam generation part 30A and the irradiation The chamber 101A can also be eliminated so that there is only beam transmission in the XY plane.

The first and second beam direction switches 22 and 23 include a deflection electromagnet for deflecting the charged particle beam P in the direction and a switching electromagnet for controlling the traveling direction of the charged particle beam P. The boron neutron capture therapy system 100 may also include a beam A collector (not shown) is used to confirm the output of the charged particle beam P before treatment, etc., and the first or second beam direction switches 22 and 23 can make the charged particle beam P deviated from the regular orbit and lead to the beam collector .

The first transmission part 21 , the second transmission part 24 and the third, fourth and fifth transmission parts 25A, 25B and 25C are all constructed by the transmission tube C, which can be formed by connecting a plurality of sub-transmission parts respectively. The direction can be the same or different, such as the deflection of the beam transmission direction by the deflection electromagnet, the transmission of the first, second, third, fourth and fifth transmission parts 21, 24, 25A, 25B, 25C The direction can be the transmission direction of any of the sub-transmission parts, and the first plane and the second plane formed above are the planes formed between the sub-transmission parts directly connected to the beam direction switch; they can also respectively include used for charged particles A beam adjustment unit (not shown) for the beam P, the beam adjustment unit includes a horizontal steering gear and a horizontal vertical steering gear for adjusting the axis of the charged particle beam P, and four steering gears for suppressing the divergence of the charged particle beam P. A polar electromagnet, and a four-way cutter for shaping the charged particle beam P, etc. The third, fourth, and fifth transmission sections 25A, 25B, and 25C may include a current monitor (not shown) and a charged particle beam scanning section (not shown) as needed. The current monitor measures the current value (ie, electric charge, irradiation dose rate) of the charged particle beam P irradiated to 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.

The charged particle beam generation chamber 102 may include an accelerator chamber 1021 and a beam delivery chamber 1022, the accelerator chamber 1021 is two floors, and the accelerator 10 extends from L2 to L1. The beam transfer chamber 1022 is located at L2, and the first transfer part 21 extends from the accelerator chamber 1021 to the beam transfer chamber 1022. The irradiation chambers 101B and 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. It can be understood that the opposite configuration is also possible. The material of the floor (ceiling) S may be concrete with a thickness of 0.5 m or more or boron-containing barite concrete. The irradiation chambers 101A, 101B, 101C and the beam transmission chamber 1022 have a shielding space surrounded by a shielding wall W1, and the shielding wall W1 can be a boron-containing barite concrete wall with a thickness of 1 m or more and a density of 3 g/c.c. The beam delivery chamber 1022 is separated from the first partition shield wall W2 of the irradiation chambers 101B, 101C and the second partition wall W3 of the accelerator chamber 1021 and the beam delivery chamber 1022 is separated at L1, and the accelerator chamber 1021 and the irradiation chamber 101A are separated at L2 The third separation shielding wall W4. The accelerator chamber 1021 is surrounded by a concrete wall W having a thickness of 1 m or more, a second partition shield wall W3, and a third partition shield wall W4. At least a part of the neutron beam generating parts 30B and 30C is embedded in the first partition shielding wall W2, and the fourth and fifth transmission parts 25B and 25C extend from the beam transmission chamber 1022 to the neutron beam generating parts 30B and 30C; The beam generation section 30A is located in the irradiation chamber 101A, and the third transfer section 25A extends from the beam transfer chamber 1022 through the floor S to the irradiation chamber 101A. The irradiation chambers 101A, 101B, and 101C respectively have screen doors D1, D2, and D3 for the treatment table 40 and physicians to enter and exit, and the accelerator room 1021 has screen doors D4 and D5 for entering and leaving the accelerator 1021 room at L1 and L2, respectively, for maintenance of the accelerator 10. The beam transfer chamber 1022 has a shield door D6 for maintaining the beam transfer unit 20 from the accelerator chamber 1021 into and out of the beam transfer chamber 1022, and the shield door D6 is provided on the second partition shield wall W3. The interiors of the irradiation chambers 101A, 101B, and 101C also have an inner shielding wall W5 to form a labyrinth channel from the shielding doors D1, D2, D3 to the beam exit, preventing direct radiation from the shielding doors D1, D2, and D3 when they are accidentally opened. For irradiation, the inner shielding wall W5 can be set at different positions according to different layouts of the irradiation chamber, and a shielding door D7 inside the irradiation chamber can also be set between the inner shielding wall W5 and the shielding wall W1 or the third partition shielding wall W4, which is formed in the Secondary protection during neutron beam irradiation therapy. The inner shielding wall W5 can be a boron-containing barite concrete wall with a thickness of 0.5m or more and a density of 3g/c.c. D and the secondary screen door D' or only the main screen door D or the sub screen door D', which can be determined according to the actual situation. The main screen door D can be made of the same material with a thickness of 0.5m or more and a density of 6g/c.c. Boron-containing PE or barite concrete or lead, the secondary screen door D' can be boron-containing PE or barite concrete or lead with a thickness of 0.2m or more and a density of 6g/c.c. of the same material. In this embodiment, the screen doors D1, D4, D5, and D6 are composed of a main screen door D and a sub screen door D'. The screen doors D1, D2, and D3 only include the main screen door D, and the screen door D7 only includes the sub screen door D. '. The shielding wall and the shielding door form a shielding space, and suppress radiation from entering the room from the outside of the irradiation chambers 101A, 101B, 101C and the beam transfer room 1022 and radiation from the room to the outside. In this embodiment, the second partition shielding wall W3 separating the accelerator chamber 1021 and the beam transmission chamber 1022 is provided between the accelerator 10 and the first beam direction switcher 22 , that is, the first transmission part 21 passes through the second partition The shielding wall W3, it can be understood that the second separating shielding wall W3 and the shielding door D6 can be canceled, and can also be arranged in other positions, such as between the first and second beam direction switchers 22, 23 or the second beam direction switcher 23 and the neutron beam generating parts 30B, 30C; or between the second dividing shielding wall W3 and the first dividing shielding wall W2, additional dividing shielding walls and shielding doors are provided. That is to say, a shielding wall is provided between the neutron beam generation part and the accelerator, so that the operator can be prevented from being irradiated by neutrons and other radiation leaked from the neutron beam generation part during the repair and maintenance of the accelerator, and at the same time, the accelerator is reduced by neutrons. activated reaction.

5 , the beam shaping body 31 is supported by the support module 60 disposed in the partition wall 103 (the first partition shield wall W2 ), and the side of the partition wall 103 close to the irradiation chamber 101 is provided with at least a part of the support module 60 . Slot 1031. A slot 1032 for the transmission tube of the accelerator to pass through is provided on the side close to the charged particle beam generation chamber 102, so that the accommodating slot 1031 and the slot 1032 pass through the partition wall in the transmission direction of the neutron beam N. In this embodiment, The wall surface of the partition wall 103 is a plane, and the transmission direction of the neutron beam N is perpendicular to the wall surface of the partition wall 103 . The support structure is modular, so that the beam shaping body can be locally adjusted to meet the accuracy requirements, improve the beam quality and meet the assembly tolerance of the target. On a plane perpendicular to the transmission direction of the neutron beam N, the cross-sectional profile of the support module 60 is located between the cross-sectional profiles of the accommodating grooves 1031 and 1032, thereby avoiding the occurrence of through-slits in the beam transmission direction and further reducing radiation, At the same time, it is convenient to adjust the support module 60 . In this embodiment, the support module 60 is a cuboid as a whole, the cross-sections of the accommodating grooves 1031 and 1032 perpendicular to the transmission direction of the neutron beam N are both "徂"-shaped, and the side walls of the accommodating grooves 1031 and 1032 are parallel to the neutron beam N. Beam N propagation direction. The side of the partition wall 103 close to the irradiation chamber 102 is also provided with a shielding plate 1033, which can enhance the shielding effect of the partition wall and suppress secondary radiation generated by the partition wall, thereby avoiding radiation to the normal tissue of the patient. On a plane perpendicular to the transmission direction of the neutron beam N, the shielding plate 1033 may match the cross-sectional profile of the support module 60, thereby shielding neutrons leaking from between the support module and the partition wall. The shielding plate is a PE plate. It can be understood that shielding plates can also be provided on the side of the partition wall 103 close to the charged particle beam generation chamber 102 and the side of the support module 60 close to the irradiation chamber 101. The shielding plates can be made of lead and other neutrons or photons. It is made of shielding material, and a shielding plate may not be provided.

The outgoing directions of the neutrons generated by the interaction between the charged particle beam P and the target T are almost distributed in space. At the same time, during the "shaping" process of the neutrons by the beam shaping body 31, a large number of recoil neutrons will be generated. Recoil neutrons are an important consideration in radiation shielding design. Closed shielding cannot be achieved where the shielding wall or floor is passed through by components or elements, which may easily cause leakage of neutrons and other radiation rays. For example, in this embodiment, the neutron beam generating parts 30B and 30C pass through the first partition The shielding wall W2, the first transmission part 21 pass through the second dividing shielding wall W3, the third transmission part 25A passes through the floor S, and the first dividing shielding wall W2, the second dividing shielding wall W3, and the floor S face the beam transmission direction The first shielding body 70 , the second shielding body 80 and the third shielding body 90 may be provided on the upstream side where the neutron beam generating parts 30B and 30C, the first transmission part 21 , and the third transmission part 25A pass through, respectively. The first shielding body 70 covers the ends of the neutron beam generating parts 30B and 30C facing the accelerator to prevent neutrons overflowing or reflecting from the beam shaping bodies of the neutron beam generating parts 30B and 30C from entering the accelerator chamber 1021 and the beam transmission chamber 1022 , the fourth and fifth transmission parts 25B and 25C pass through the first shielding body 70 to reach the targets T of the neutron beam generating parts 30B and 30C. The second shield body 80 prevents neutrons overflowing or reflected from the beam transmission part 20 from entering the accelerator chamber 1021 , and the first transmission part 21 passes through the second shield body 80 and the second partition shield wall W3 to reach the first beam direction switcher twenty two. The third shield 90 prevents neutrons overflowing or reflected from the irradiation chamber 101A from entering the beam transmission chamber 1022, and the third transmission portion 25A passes through the third shield 90 and the floor S to reach the neutron beam generating portion 30A. The material of the first shielding body 70 , the second shielding body 80 and the third shielding body 90 may be boron-containing PE or barite concrete or lead, and may also include other neutron shielding materials.

The first, second and third shielding bodies 70 , 80 and 90 will be described in detail below by taking the first shielding body 70 as an example. In one embodiment, the first shielding body 70 is movable, and is movably installed on the side of the first partition shielding wall W2 toward the upstream of the beam transmission direction (the side close to the charged particle beam generation chamber 102) by the installation mechanism 70A. ), and has a first position and a second position. At the first position, the receiving holes 71 through which the fourth and fifth transmission parts 25B and 25C pass are formed, and cover the ends of the neutron beam generating parts 30B and 30C facing the accelerator 10, so as to shield the recoil neutrons and limit the dose of high neutrons zone, protect the accelerator components, reduce the radiation damage of the components, reduce the element activation of the accelerator components, and at the same time, when one irradiation chamber is operating, protect the other irradiation chamber to ensure that the radiation dose of the non-operating irradiation chamber is at a safe level; in the second position, the accommodating hole 71 is open to expose the ends of the neutron beam generating parts 30B and 30C facing the accelerator 10, and the operation space is formed without removing the transfer tube C passing through the accommodating hole 71, and the neutron beam can be replaced when the accelerator 10 is closed The generating parts 30B and 30C, such as the target material T, the beam shaping body 31, the radiation detection components provided in the beam shaping body 31 or the first and second cooling pipes 3012 and 3013, can also be used to remove part of the transmission pipes during replacement. Make space, or perform installation, debugging, and maintenance on the beam transmission part 20 passing through the first partition shield wall W2 and the first shield body 70 . The accommodating holes can accommodate the transmission tubes C, magnets, etc. of the fourth and fifth transmission parts 25B and 25C, as well as the first and second cooling tubes 3012, 3013 or other functional components, which can be easily moved to provide operating space without disturbing the Immovable component of the beam delivery section. The first shielding body 70 and the first separating shielding wall W2 may be in airtight contact to enhance the shielding effect, or may have a gap, and the shielding effect may be achieved by adjusting the size of the first shielding body 70 .

As shown in FIG. 6 and FIG. 7 , in this embodiment, the first shielding body 70 includes a first shielding portion 72 and a second shielding portion 73 , and the first shielding portion 72 and the second shielding portion 73 are generated along the neutron beams, respectively. The first and second directions L1, L2 of the parts 30B, 30C move to the first position, the first shielding part 72 and the second shielding part 73 respectively have first and second grooves 721, 731, the first and second grooves The grooves 721 and 731 together form a receiving hole 71 through which the fourth and fifth transmission parts 25B and 25C pass through at the first position, and cover the ends of the neutron beam generating parts 30B and 30C facing the accelerator 10; the first shielding part 72 and the The second shielding portion 73 moves to the second position along the third and fourth directions L3 and L4 away from the neutron beam generating portions 30B and 30C, respectively. At the second position, the accommodating hole 71 is opened to expose the neutron beam generating portion 30B, 30C is toward the end of the accelerator 10 , and an operation space is formed without removing the transfer tube C passing through the receiving hole 71 . It can be understood that the first shielding body 70 may also include a third shielding portion or be composed of three or more shielding portions.

In this embodiment, the first shielding portion 72 and the second shielding portion 73 are slidable, and the guide rail 74 and the rollers 75 fixed on the first and second shielding portions 72 and 73 constitute the sliding assembly (installation) of the first shielding body 70 Mechanism 70A), the roller 75 rolls along the guide rail 74 to drive the first and second shielding parts 72, 73 to slide along the guide rail 74, and the guide rail 74 is fixed on the side of the first partition shielding wall W2 facing the charged particle beam generation chamber 102 and in the extending direction Parallel to the ground (XY plane), that is, the first and second shielding parts 72 and 73 are configured as horizontal double-opening sliding doors. It can be understood that the installation mechanism 70A can have other settings, and can also be moved in other ways, such as rotation, etc. .

As shown in FIG. 8 , in another embodiment, the installation mechanism 70A' includes a guide rail 701a (74') and a roller 702a (75'), and the guide rail 701a is directly fixed on the first partition shielding wall W2 by expansion screws, referring to FIG. 9 . 11b, the roller 702a is connected to the connecting plate 704a fixed with the first and second shielding parts 72 and 73 through a first connecting piece 703a (such as a bolt and nut). One end of the bolt (eg, through a bearing), the other end of the bolt passes through the connecting plate 704a and is tightened on both sides of the connecting plate 704a by nuts. It can be understood that the guide rail 701a and the roller 702a can also have other fixing methods. The installation mechanism 70A' also includes a first frame 705a1 for fixing the first shielding portion 72, and a second frame 705a2 for fixing the second shielding portion 73 (wherein, the second frame has the same structure and function as the first frame, which is not shown in the figure. ), the first and second shielding parts 72, 73 are constructed of multiple plates, and the multi-speed plates are spliced and fixed to the first frame 705a1 and the second frame 705a2 of the first and second shielding parts 72, 73, respectively. The tops of the first frame 705a1 and the second frame 705a2 are fixed with a connecting plate 704a, thereby forming a hanging rail. Referring to FIG. 10 , the bottom of the first frame 705a1 and the second frame 705a2 can also be fixed with a chute 706a, and the chute 706a cooperates with the wheel 707a fixed on the shielding wall W2 to form the first and second shielding parts 72, 73 along the guide rails The auxiliary limit of the horizontal sliding of the 701a prevents the first and second shielding parts 72, 73 and their first frames 705a1 and 705a2 from turning over in a direction perpendicular to the shielding wall W2. The first frame 705a1 and the second frame 705a2 are constructed of aluminum alloy profiles. The radioactive half-life of the product after being irradiated by neutrons is short, which reduces the secondary radiation generated. The first and second shielding parts 72 and 73 are PE plates containing boron , it can be understood that the first frame 705a1 and the second frame 705a2 can also use other products irradiated with neutrons that do not have radioactivity, or the products irradiated with neutrons have low radioactivity or are irradiated with neutrons. The half-life of radioisotopes For short materials, other neutron shielding materials can also be used for the first and second shielding parts 72 and 73 .

The neutron capture therapy system 100 may further include a driving mechanism 70B of the first shielding body 70, the driving mechanism 70B drives the movement of the first shielding body 70, and the driving mechanism 70B includes an air cylinder 701b, a connecting rod 702b, a chain 703b, a sprocket 704b, a connection Block 705b. Air is supplied to the cylinder block of the cylinder 701b through the air supply device (not shown) to drive the piston of the cylinder 701b, and the piston of the cylinder 701b is connected to the first frame 705a1 of the first shielding portion 72 through the connecting rod 702b, thereby driving the first shielding The part 72 moves, specifically, the piston moves in the horizontal direction, one end of the piston of the cylinder 701b extends into the cylinder of the cylinder 701b, and the other end is connected with the connecting rod 702b, the connecting rod 702b is fixed to the first frame 705a1 of the first shielding part 72 away from The side of the second shielding part 73; the chain 703b is located on both sides of the sprocket 704b and is connected to the first frame 705a1 and the second frame 705a2 of the first and second shielding parts 72 and 73 through the connecting blocks 705b, respectively. The first shielding part The movement of 72 drives the second shielding portion 73 to move in the opposite direction through the chain 703b, so as to reach the first position or the second position. Specifically, one end of the connecting block 705b is fixed to the top of the frame 705a, and the other end and the chain 703b pass through the tooth clip combine. It can be understood that in this embodiment, the connecting rod 702b, the chain 703b, the sprocket 704b, and the connecting block 705b constitute the transmission member of the driving mechanism 70B, and the transmission member is connected with the piston of the cylinder 701b. It can be understood that the transmission member may also have other A buffer member 706b can also be provided. When the first shielding portion 72 is about to move to the end position in a direction away from the second shielding portion 73, the connecting rod 702b contacts the buffering member 706b to prevent impact from collision; a stop member can also be provided 707b (such as a fixed screw), the stop member 707b acts with the connecting rod 702b to limit the maximum distance that the first shielding portion 72 moves in the direction away from the second shielding portion 73; there may also be other driving methods, such as driving by a motor The first or second shield moves. The driving mechanism 70B further includes a fixing bracket 708b, and the fixing bracket 708b is fixed on the shielding wall W2 through a second connecting piece 709b (as shown in FIG. 11d ). 706b, stop member 707b) can be fixed on the fixing bracket 708b.

The neutron capture therapy system 100 can also control the operation of the driving mechanism 70B through a control mechanism (not shown), thereby controlling the movement of the first shielding body 70, and the control mechanism can be arranged outside the charged particle beam generation chamber 102, such as a control room (as described below), the control mechanism is prevented from being activated by neutrons and failing.

Each component of the mounting mechanism 70A, 70A' or the driving mechanism 70B may be made of products that are not radioactive after being irradiated by neutrons, or that the products that are irradiated by neutrons have low radioactivity or that are irradiated by neutrons. It is made of material, such as aluminum alloy, but due to the requirements of mechanical properties, some components in this embodiment are still made of steel, such as the components that carry the driving force (such as the cylinder block of the cylinder 701b ) and the connections that carry the first shielding body 70 (the first connecting piece 703a), the connecting piece (the second connecting piece 709b) carrying the driving mechanism 70B, after the steel is irradiated with neutrons, a radioisotope with a long half-life, such as cobalt 60, needs to be provided with a neutron shielding structure 70C. Block and reduce the secondary radiation generated by the installation mechanism or the driving mechanism after being irradiated by neutrons. As shown in Fig. 11a, a collar 701c is provided on the periphery of the cylinder body of the cylinder 701b. As shown in FIG. 11b, a cap sleeve 702c is provided outside the first connecting piece 703a, and the cap sleeve 702c covers the part of the first connecting piece 703a protruding from the connecting plate 704a at one end passing through the connecting plate 704a (nuts and bolts pass through the connecting plate 704a) A collar 703c can also be set to shield other exposed parts of the first connecting piece 703a, such as the part where the bolt passes through the connecting plate 704a and is located between the two side plates of the connecting plate 704a (the first connecting piece is connected to the It is understood that the bolts pass through the connecting plate 704a and are located between the two side plates of the connecting plate 704a due to space constraints, as shown in Figure 11c , the collar 703c' can also cover the bolt from the outside of the connecting plate 704a. As shown in the Z-direction schematic diagram in FIG. 11d , without affecting the connection relationship of the mechanism, the cover body 705c can also be integrally covered outside the connecting plate 704a to the connecting plate 704a and the first connecting piece 703a passing through the connecting plate 704a as a whole. For shielding, the cover 705c can be

The frame 705a surrounds the connecting plate 704a and the first connecting piece 703a passing through the connecting plate 704a. It can be understood that the cover body 705c may also include a top. The secondary radiation shielding effect after the sub-radiation is better.

As shown in FIG. 11e, a baffle plate 704c is provided outside the second connecting piece 709b, and the baffle plate 704c is fixed on the fixing bracket 708b. The side upstream of the beam propagation direction (the side close to the charged particle beam generation chamber 102 ) shields the recoil neutrons. In another embodiment, as shown in Figure 11f, the baffle 704c' is

The recoil neutrons are shielded on the upper side, the lower side and the side facing the upstream of the beam transmission direction (the side close to the charged particle beam generating chamber 102 ) of the second connecting member 709b. It can be understood that the baffles 704c and 704c' may further include side parts to form a circumferential closure to enhance the radiation shielding effect. As shown in Fig. 11g, the baffles 704c' also cover the second connecting piece 709b with a side part.

The material of the neutron shielding structure 70C may include boron-containing resin, boron-containing glass fiber composite material, etc. It can be understood that the form and position of the neutron shielding structure 70C can also be set according to specific needs.

The first and second beam direction switches 22 and 23 are respectively surrounded by a shielding cover 26 to prevent the leakage of neutrons and other radiation from the beam direction switcher. The material of the shielding cover 26 can be PE or barite containing boron concrete or lead. It can be understood that the first and second beam direction switches 22 and 23 can also be surrounded by a shielding cover 26 as a whole; other parts of the beam transmission part, such as vacuum tubes, can also be surrounded by a shielding cover to prevent neutrons and other radiation Wire leaks from the beam delivery section.

The boron neutron capture therapy system 100 may further include a preparation room, a control room and other spaces for auxiliary treatment, and each irradiation room may be configured with a preparation room for fixing the patient to the treatment table, injecting boron drugs, For preparations such as treatment plan simulation, a connecting channel is set between the preparation room and the irradiation room. After the preparation is completed, the patient is directly pushed into the irradiation room or controlled by the control mechanism through the track to enter the irradiation room automatically. The preparation room and the connecting channel are also shielded by The walls are closed and the preparation room also has a screen door. The control room is used to control the accelerator, beam transmission unit, treatment table, etc., to control and manage the entire irradiation process, and managers can also monitor multiple irradiation rooms at the same time in the control room.

It can be understood that the shielding wall (including the concrete wall W), the shielding door, the shielding body, and the shielding cover in this embodiment can all have other thicknesses or densities or be replaced with other materials.

Although the illustrative specific embodiments of the present invention have been described above to facilitate the understanding of the present invention by those skilled in the art, it should be clear that the present invention is not limited to the scope of the specific embodiments. For those skilled in the art, Various changes, which are obvious, are within the scope of the claimed invention, provided they are within the spirit and scope of the invention as defined and determined by the appended claims.

Claims (15)

1. A neutron capture treatment system, comprising an accelerator, a beam transmission part, and a neutron beam generation part, wherein the accelerator accelerates charged particles to generate a charged particle beam, and the beam transmission part converts the charged particle beam generated by the accelerator transmitted to the neutron beam generating unit, and the neutron beam generating unit generates a neutron beam for treatment, characterized in that the neutron capture therapy system further includes a formation accommodating the accelerator, a beam transmission unit, and a neutron beam. A shielding wall in the space of the beam generating unit is provided with a shielding body at a portion where the beam transmitting unit or the neutron beam generating unit passes through the side of the shielding wall facing upstream in the beam transmitting direction, and the neutron beam generating unit The capture therapy system further includes a mounting mechanism or a driving mechanism for the shielding body, the mounting mechanism for movably mounting the shielding body on the side of the shielding wall facing upstream in the beam transmission direction, the driving mechanism For driving the shielding body to move, the mounting mechanism is provided with a first neutron shielding structure or the driving mechanism is provided with a second neutron shielding structure.
2. The neutron capture therapy system according to claim 1, wherein the installation mechanism comprises a first connecting member carrying the shielding body, and the first neutron shielding structure covers the exposed portion of the first connecting member part.
3. The neutron capture therapy system according to claim 2, wherein the installation mechanism comprises a guide rail and a roller, the guide rail is fixed on the side of the shielding wall facing upstream in the beam transmission direction, and the roller passes through the The first connecting piece is fixed on the shielding body, and the shielding body can slide along the guide rail through the roller.
4. The neutron capture therapy system of claim 3, wherein the mounting mechanism comprises a frame, the shielding body is a plate fixed to the frame, a connecting plate is fixed on the top of the frame, and the roller passes through The first connecting piece is fixed to the connecting plate.
5. The neutron capture therapy system according to claim 4, wherein the first connecting member passes through the connecting plate, the roller is mounted on one end of the first connecting member, and the first neutron The shielding structure covers the part of the other end of the first connecting piece protruding from the connecting plate, or covers the part of the first connecting piece between the roller and the connecting plate, or covers the first connecting piece and the connecting plate. The connecting plate overlaps and partially or entirely covers the connecting piece and the connecting plate with bare parts.
6. The neutron capture therapy system of claim 1, wherein the driving mechanism comprises a fixed bracket and a second connecting member carrying the driving mechanism, the fixed bracket being fixedly mounted to the said fixed bracket through the second connecting member A shielding wall, the second neutron shielding structure includes a baffle shielding the second connecting piece.
7. The neutron capture therapy system according to claim 6, wherein the baffle is fixed on the fixing bracket, and the baffle is L-shaped or

   

   shape or circumferential closure.
8. The neutron capture therapy system of claim 1, wherein the driving mechanism further comprises an air cylinder, the air cylinder comprises a cylinder body, and the second neutron shielding structure comprises a collar covering the periphery of the cylinder body .
9. 9. The neutron capture therapy system of claim 8, wherein the cylinder is fixed to the shielding wall, the cylinder further comprises a piston, one end of the piston protrudes into the cylinder, the piston The other end is connected to the shield.
10. The neutron capture therapy system according to claim 9, wherein the driving mechanism further comprises a transmission member connected with the piston, the shielding body comprises a first shielding part and a second shielding part, the first shielding part The first shielding portion and the second shielding portion move in opposite directions under the driving of the air cylinder and the transmission member.
11. The neutron capture therapy system of claim 10, wherein the transmission member comprises a sprocket and chains located on both sides of the sprocket, and the chains on both sides of the sprocket are respectively connected to the first shield part and the second shield part.
12. The neutron capture therapy system according to claim 11, wherein the installation mechanism further comprises first and second frames for fixing the first shielding portion and the second shielding portion, respectively, and the sprocket is on both sides of the sprocket. The chains are fixedly connected to the first and second frames, respectively, the piston is connected to the first frame or the second frame, and the first shielding part and the second shielding part are between the piston and the chain. Drive down to move in the opposite direction.
13. The neutron capture therapy system according to claim 12, wherein the material of the first and second shielding parts is PE containing boron, and the material of the first and second frames is aluminum alloy.
14. The neutron capture therapy system according to claim 1, wherein the material of the first and second neutron shielding structures is a boron-containing resin or a boron-containing glass fiber composite material.
15. The neutron capture therapy system according to claim 2, 6 or 8, wherein the material of the first connecting member is steel, the material of the second connecting member is steel, and the material of the cylinder is steel.

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