TW201912201A - Neutron capture therapy system - Google Patents

Abstract

The present application provides a neutron capture therapy system. The neutron capture therapy system comprises an accelerator for generating a charged particle beam, a neutron generating portion for generating a neutron beam after irradiation by the charged particle beam, and a beam shaping body for shaping the neutron beam. The beam shaping body comprises a retarding body and a reflecting portion coated on the periphery of the retarding body. The neutron generating portion generates neutrons after irradiation by the charged particle beam. The retarding body decelerates, to a preset energy spectrum, the neutrons generated by the neutron generating portion. The reflecting portion comprises a reflecting body capable of guiding deviated neutrons to increase neutron intensity in the preset energy spectrum and a supporting member capable of supporting the reflecting body. By using a lead-antimony alloy as the reflecting body, thus improving on the creep effect that arises from using only a lead material, structural strength of the beam shaping body is improved.

Description

   Neutron Capture Therapy System   

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

With the development of atomic science, radiation therapy such as cobalt sixty, linear accelerator, electron beam 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. While killing tumor cells, it will also cause damage to a large number of normal tissues in the beam path. In addition, due to the different sensitivity of tumor cells to radiation, traditional radiation therapy Treatment of radiation-resistant malignancies (eg, glioblastoma multiforme, melanoma) is often not effective.

In order to reduce radiation damage to normal tissues surrounding tumors, the concept of target therapy in chemotherapy has been applied to radiation therapy. At the same time, tumor cells with high radiation resistance have also been actively developed with high relative biological effects. 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, which uses boron-containing drugs to specifically accumulate in tumor cells and cooperates with precise neutron beam regulation to provide better than traditional radiation. Cancer treatment options.

Boron Neutron Capture Therapy (BNCT) is the use of boron-containing ( ¹⁰ B) drugs with high capture cross-section characteristics for thermal neutrons. It is generated by ¹⁰ B (n, α) ⁷ Li neutron capture and mitotic reactions. ⁴ He and ⁷ Li are two heavily charged particles. Referring to the first figure, it is a schematic diagram of the boron neutron capture reaction. The average energy of two charged particles is about 2.33 MeV. It has high linear energy transfer (LET) and short range characteristics. The range is 150keV / μm, 8μm, and the 7Li heavy-loaded particles are 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. Drugs can be selectively concentrated in tumor cells and, with appropriate neutron emission sources, can achieve the purpose of locally killing tumor cells without causing much damage to normal tissues.

In the accelerator boron neutron capture therapy, on the one hand, neutrons or other particles generated by the neutron generating section, such as gamma rays, are radioactive, and on the other hand, neutrons generated by the neutron generating section usually need to be adjusted by a beam shaper. To improve the neutron yield, it is necessary to install a reflector to reduce the radiation leakage rate of particles, adjust the energy spectrum and increase the neutron yield. Lead is a material traditionally used for reflection or shielding, however, the creep effect of lead is significant and cannot provide structural rigidity and long service life. For boron neutron capture therapy, the quality of the neutron beam is not only related to the beam shaper, but also to the reflector and the shield. Lead is usually used as a reflective material in the prior art, but the creep effect of lead will lead to insufficient structural accuracy, which will affect the safety of the entire boron neutron capture treatment.

Therefore, it is necessary to provide a new neutron capture therapy system to overcome the above technical problems.

One aspect of the present invention provides a neutron capture therapy system capable of improving the strength / precision of the beam shaper structure without significantly affecting the quality of the neutron beam. The neutron capture therapy system includes an accelerator for generating a charged particle beam, a neutron generating section for generating a neutron beam upon irradiation with the charged particle beam, and a beam shaper for shaping the neutron beam. The beam shaping body includes a retarder and a reflecting part covering the periphery of the retarder. The neutron generating section generates neutrons after being irradiated by the charged particle beam, and the retarder will generate neutrons from the neutron generating section. Decelerating to a preset energy spectrum, the reflecting portion includes a reflector capable of directing deviated neutrons to increase the neutron intensity within the preset energy spectrum, and a support capable of supporting the reflector.

Further, the reflecting portion includes a plurality of cells, each of which forms a core with an accommodation space, the plurality of cores are connected to form the support, and the reflector is provided in the capacity of the core. Space.

Further, the support member is an integrally formed structure, and the reflector material is cast and disposed in the accommodation space of the core portion.

As a preferred embodiment, the reflecting part is modularized, specifically, a support member formed by connecting a predetermined number of cores is provided, and an outer side of the support member is provided with a top plate and a bottom plate opposite to each other, and the top plate and the bottom plate are connected and connected to each other. A side plate surrounding the periphery of the core, the predetermined number of connected cores, the reflector, the top plate, the bottom plate, and the side plate provided in the core form a reflector module, and the reflector modules are stacked to form the reflector. Considering the convenience of stacking the subsequent reflector modules, the prescribed number in the preferred embodiment is 20.

In order to minimize the influence of the materials of the core, the top plate, the bottom plate and the side plate on the quality of the neutron beam, the materials of the core, the top plate, the bottom plate and the side plate in this application are low neutron absorption cross sections and low activation alloy materials. The ratio of the total volume of the alloy material to the volume of the reflector material is less than 10%.

Preferably, the material of the reflector is lead, and the material of the core, the top plate, the bottom plate, and the side plate is an aluminum alloy or a lead-antimony alloy.

In order to solve the above technical problem, another aspect of the present invention provides a neutron capture treatment system, which can improve the strength / precision of the beam shaper structure without significantly affecting the quality of the neutron beam. The neutron capture treatment device includes an accelerator for generating a charged particle beam, a neutron generating section for generating a neutron beam upon irradiation with the charged particle beam, and a beam shaping body for shaping the neutron beam. The beam shaping body includes a retarder and a reflecting part covering the periphery of the retarder. The neutron generating section generates neutrons after being irradiated by the charged particle beam, and the retarder will generate neutrons from the neutron generating section. Decelerating to a preset energy spectrum, the reflecting portion guides the deviated neutrons back to increase the intensity of the neutrons within the preset energy spectrum. The reflecting portion is also covered with a shielding portion on the periphery, and the shielding portion includes a support member and A shield provided in the support.

Further, the shielding unit includes a plurality of grid cells, and each grid unit forms a core part with a containing space, the shielding body is disposed in the containing space of the core part, and a plurality of core parts are connected to form a core. In the support member, the support member is an integrally formed structure, and the shield material is cast and disposed in an accommodation space of the core portion.

As a preferred method, the shielding part is modularly designed. Specifically, a support plate formed by connecting a predetermined number of cores is provided with a top plate and a bottom plate opposite to each other, and a core plate connected to the top plate and the bottom plate and surrounding the core. A side plate, the predetermined number of connected cores, a shield body, a top plate, a bottom plate and a side plate provided in the core portion form a shield body module, the shield body modules are stacked to form the shield portion, and the shield material is lead The material of the core, the top plate, the bottom plate, and the side plate is a low neutron absorption cross section and a low activation material. The total volume of the material of the core, the top plate, the bottom plate, and the side plate accounts for less than 10 of the material volume of the reflector. %. Considering the convenience of stacking between subsequent shield modules, the prescribed number in this application is 20.

Further, the reflecting portion includes a reflector capable of guiding deviated neutrons back to increase the neutron intensity within a preset energy spectrum, and a support member capable of supporting the reflector.

Compared with the prior art, the neutron capture treatment system of the present application supports a reflective material or / and a shielding material by providing a supporting member of a reflecting portion or / and a supporting member of a shielding portion, that is, a low neutron absorption and low activation alloy The material supports the lead material to overcome the creep effect of the lead material, and improves the structural strength of the beam shaper without affecting the quality of the neutron beam.

100‧‧‧ Neutron Capture Therapy System

10‧‧‧ Neutron Generation Department

20‧‧‧ Beam Shaping Body

21‧‧‧ Slow body

22‧‧‧Reflection

221‧‧‧Support

222‧‧‧Reflector

223‧‧‧cell

224‧‧‧accommodation space

225‧‧‧Core

226‧‧‧Top plate

227‧‧‧ floor

228‧‧‧Side

229‧‧‧Reflector Module

30‧‧‧ Collimator

40‧‧‧Shield Department

41‧‧‧Support

42‧‧‧shield

43‧‧‧cell

44‧‧‧ accommodation space

45‧‧‧ Core

46‧‧‧Top plate

47‧‧‧ floor

48‧‧‧Side

49‧‧‧Shield Module

200‧‧‧ accelerator

P‧‧‧Charged particle beam

N‧‧‧ Neutron Beam

W‧‧‧shield wall

FIG. 1 is a schematic diagram of a boron neutron capture treatment device in an embodiment of the present invention.

FIG. 2 is a schematic diagram of a neutron capture therapy system installed on a shielded wall according to the first embodiment of the present application, which has a shield portion, and only the shield portion has a support member.

FIG. 3 is a schematic diagram of a core structure of the shielding portion in the first embodiment of the present application.

FIG. 4 is an exploded view of the shield module when the shield material is not provided in the first embodiment of the present application.

FIG. 5 is a schematic diagram of a neutron capture treatment system installed on a shielded wall in Embodiment 2 of the present application, wherein the beam shaper does not have a shield portion, and only the reflection portion has a support member.

FIG. 6 is a schematic diagram of a core structure of the reflecting portion in Embodiment 2 of the present application.

FIG. 7 is an exploded view of the reflector module in a state where no reflector material is provided in Embodiment 2 of the present application.

FIG. 8 is a schematic diagram of a neutron capture treatment system installed on a shielded wall in Embodiment 3 of the present application, in which both the reflection part and the shield part have support members.

The embodiments of the present invention are further described in detail below with reference to the accompanying drawings, so that those skilled in the art can implement the present invention with reference to the description text.

The particles (such as neutrons) generated by the accelerator need to be installed with a reflector to reduce the radiation leakage rate of the particles, and a shield must be installed to provide radiation safety shielding. Lead or lead alloys are traditionally used as materials for reflection or shielding. However, the creep effect of lead is significant and cannot provide structural rigidity and long service life.

As shown in FIG. 2, the present application provides a neutron capture treatment system 100. The neutron capture treatment system 100 includes an accelerator 200 for generating a charged particle beam P, and a neutron beam is generated after irradiation with the charged particle beam P. The neutron generator 10, a beam shaper 20 that shapes the neutron beam, and a collimator 30. The beam shaping body 20 includes a retarder 21 and a reflecting portion 22 covering the outer periphery of the retarder. The neutron generating unit 10 generates a neutron beam N after being irradiated with a charged particle beam, the retarder 21 reduces the neutron beam N generated from the neutron generating unit 10 to a preset energy spectrum, and the reflecting unit 22 The deviated neutrons are guided back to increase the neutron intensity within a preset energy spectrum, and the collimator 30 concentrates the neutrons generated by the neutron generator 10.

As a first embodiment, the neutron capture treatment system 100 further includes a shielding portion 40. With reference to FIG. 3, the shielding portion 40 includes a supporting member 41 and a shielding body 42 disposed in the supporting member 41. The support member 41 includes a plurality of grid elements 43, each grid element 43 forms a core portion 45 having an accommodation space 44, the shield body 42 is disposed in the accommodation space 44, and a plurality of core portions 45 are connected to form a core. Mentioned support 41. As a preferred embodiment, the supporting member 41 is an integrally formed structure, and the shielding material is poured into the accommodating space 44 of each core portion 45 of the supporting member 41.

With reference to FIG. 4, a supporting member 41 formed by connecting a predetermined number of cores 45 is used. The supporting member 41 has a hexagonal cross section, which is easy to form and stack. A top plate 46, a bottom plate 47, and four side plates 48 connected to the top plate 46 and the bottom plate 47 and surrounding the outer periphery of the core 45 are provided on the outside of the support 41. The predetermined number of connected core portions 45, the shield body 42, the top plate 46, the bottom plate 47, and the side plates 48 provided in the core portion 45 form a shield body module 49. The shield body modules 49 are stacked to form the shield portion 40. . In the present application, considering the convenience of stacking the subsequent shielding body modules 49, as a preferred embodiment, the prescribed number is 20. Of course, those skilled in the art can adjust the number of side plates according to design requirements, such as three, six, and so on; and adjust the specified number of shield body modules according to design requirements, such as ten, thirty, and so on.

The material of the shielding body 42 is lead, and the top plate 46, the bottom plate 47, and the top plate 46, the bottom plate 47, and the side plate 48 are made of an alloy material with low neutron cross-section absorption and low neutron activation. In order to minimize the influence of the alloy material on the quality of the neutron beam, the proportion of the total volume of the alloy material to the volume of the shield 42 material is less than 10%.

In this embodiment, the reflecting portion 22 is a structure made of a lead material and has a creep effect. The shielding portion 40 covers the outer periphery of the reflecting portion 22, and the beam shaping body 20 is buried in the radiation chamber. In the shielding wall W in which the radiation is shielded, the shielding portion 40 is directly supported by the shielding wall W. The support 41 inside the shielding portion 40 provides support to the shielding body 42 itself and also provides strength support to the reflecting portion 22 Therefore, the structural strength of the entire beam shaping body 20 is improved.

As shown in FIG. 5, as the second embodiment, the setting of the shielding portion 40 in the first embodiment is directly applied to the reflecting portion 22, and the reflecting portion 22 is provided in a structure including a support 221 without a shield. Department 40.

With reference to FIG. 6, the reflecting portion 22 includes a support member 221 and a reflector 222 disposed in the support member 221. The support member 221 includes a plurality of grid elements 223, and each grid element 223 forms a core portion 225 having an accommodation space 224. The reflector 222 is disposed in the accommodation space 224, and a plurality of core portions 225 are connected to form a core. Mentioned support 221. As a preferred embodiment, the supporting member 221 is integrally formed, and the material of the reflector 222 is cast into the core portion 225 of the supporting member 221.

As shown in FIG. 7, the reflective portion 22 is modularized. Specifically, a support 221 formed by connecting a predetermined number of cores 225 is provided, and an outer side of the support 221 is provided with a top plate 226 and a bottom plate opposite to each other. 227 and four side plates 228 connected to the top plate 226 and the bottom plate 227 and surrounding the periphery of the core portion 225. The predetermined number of connected core portions 225, the reflector 222, the top plate 226, the bottom plate 227, and the side plate 228 provided in the core portion 225 form a reflector module 229, and the reflector modules 229 are stacked to form the reflector 22 . The top plate 226, the bottom plate 227, and the four side plates 228 connected to the top plate 226 and the bottom plate 227 and surrounding the periphery of the core 225 are alloy materials with low neutron cross-section absorption and low activation, and the total volume of the alloy material accounts for the shield The proportion of 42 material volumes is less than 10%.

FIG. 8 shows Embodiment 3 of the present application. The difference from the above embodiment is that in this embodiment, both the reflecting portion and the shielding portion have a structural design with a supporting member. In this embodiment, the The setting is the same as that of the reflecting portion in the second embodiment, and the setting of the shielding portion is the same as that of the shielding portion in the first embodiment, which will not be described in detail herein. When the beam shaping body 20 is buried in the shielding wall W, the shielding part 40 is directly supported by the shielding wall W. In this embodiment, the reflector 222 is provided by providing a support member 221 without affecting the quality of the neutron beam. Support, a support member 41 is provided to support the shielding body 42 to overcome the problem of structural accuracy caused by the creep effect of the reflector and the shielding body due to the use of lead materials.

It should be noted that, as described in the second embodiment and the third embodiment, when the reflecting portion is provided with a structure of a reflector module, the reflecting portion 22 covers the outer periphery of the retarding body 21, thereby slowing down. The outer surface of the body 21 is generally cylindrical or has at least one cone-shaped structure. Therefore, when the reflection part formed by the stack of the reflector module 229 is covered on the outer surface of the retarder 21, the structural Based on the problem, adjust the structure of the reflector module directly connected to the surface of the retarder 21, for example, cut the reflector module that is in contact with the retarder 21 to make the reflection part fit the retarder. The outer surface of 21 does not affect the reflector 222 in the reflecting portion 22 to reflect the deviated neutrons.

The core formed by the grid elements in the present application may be any closed structure having a hole-shaped accommodating space, such as a geometric structure having a square, triangular or hexagonal cross-section, a tetrahedron with a hole-shaped accommodating space, An octahedron or a dodecahedron can also be a non-closed structure with a hole-like accommodation space, which will not be illustrated one by one here. The lead is placed in the hole-shaped accommodating space by pouring, and is tightly surrounded by the core material, so that the alloy material at the core supports the lead material.

In the second and third embodiments of the present application, in order to facilitate the stacking and manufacturing of the reflector module and / or the shield module, both the core portion of the reflection portion and the core portion of the shield portion are hexagonal in cross section. structure. Of course, the structure of the supporting member of the reflecting portion may be different from the structure of the supporting member of the shielding portion. For example, the core structure of the support of the shield is a geometric shape with a hexagonal cross-section, and the core structure of the support of the reflection is a tetrahedron. As long as the alloy material of the support can support the lead material, and It is sufficient for the neutron beam quality to have a small effect, which will not be described in detail here.

Regardless of the above embodiment, for the consideration of the weight of the entire beam shaper, the material of the core, the top plate, the bottom plate, and the side plate connected to the top plate and the bottom plate and surrounding the periphery of the core is selected to be lighter. Alloy materials, combined with consideration of neutron beam quality, the core, top plate, bottom plate and side plates should also be made of low neutron absorption materials and low activation materials, and the top plate, bottom plate, side plates and core materials The total volume of the material accounts for less than 10% of the volume of the reflector material or the volume of the shield material. In this application, the material of the top plate, the bottom plate, the side plate, and the core is preferably an aluminum alloy material. Lead-antimony alloy can also be used instead of aluminum alloy, because although the neutron absorption cross section of lead-antimony alloy material is higher than that of aluminum alloy material, because the total volume of the material of the top plate, bottom plate, side plate and core occupies the reflector material The proportion of the volume of the shielding material is less than 10%, and the equivalent total antimony content is less than 1%. Therefore, the antimony in the lead-antimony alloy material has no significant effect on the neutron beam quality.

Although the reflector or / and the shield in the beam shaper described in this application are made of a lead material having a creep effect, when the beam shaper is buried in the shielding wall W of the irradiation chamber, it is supported by The reflector or the shield of the shielding wall W can support the lead material with creep effect by means of a support made of an alloy material, so the structural accuracy of the entire beam shaping body is improved.

The shielding part described in this application supports the lead material on the one hand by providing an alloy material, and on the other hand, a top plate, a low plate, and a side plate connected to the top plate and the low plate are provided on the outer periphery of the lead material supported by the alloy material to enhance shielding The modular design of the shielding part is realized at the same time as the structural strength of the shielding part, and the structure is simple. Therefore, the shielding part in the present application can also be applied to other shielding occasions.

Although the illustrative specific embodiments of the present invention have been described above so that those skilled in the art can understand the present invention, it should be clear that the present invention is not limited to the scope of the specific embodiments, and for those of ordinary skill in the art, As long as various changes are within the spirit and scope of the present invention as defined and determined by the appended claims, these changes are obvious and all fall within the scope of protection of the present invention.

Claims (10)

    A neutron capture therapy system includes: an accelerator for generating a charged particle beam; a neutron generating section for generating a neutron beam after irradiation with the charged particle beam; and a beam shaper for shaping the neutron beam; wherein The beam shaping body includes a retarder and a reflecting part covering the outer periphery of the retarder. The neutron generating part generates neutrons after being irradiated with a charged particle beam, and the retarder will generate the neutron from the neutron generating part. The generated neutron is decelerated to a preset energy spectrum, and the reflection part includes a reflector capable of guiding the deviated neutrons back to increase the neutron intensity within the preset energy spectrum, and a support capable of supporting the reflector.         The neutron capture therapy system according to item 1 of the scope of the patent application, wherein the reflecting portion includes a plurality of cells, each cell forming a core with an accommodation space, and a plurality of cores are connected to form the core. The support is provided in the accommodation space of the core.         The neutron capture treatment system according to item 2 of the scope of the patent application, wherein the support is an integrally formed structure, and the reflector material is cast and disposed in the accommodation space of the core.         The neutron capture treatment system according to item 2 of the scope of patent application, wherein the support is formed by connecting a predetermined number of cores, and the support is provided with a top plate and a bottom plate opposite to each other and connected with the top plate and the bottom plate. The side plates surrounding the core are surrounded. The predetermined number of connected cores, the reflectors, the top plate, the bottom plate, and the side plates provided in the accommodation space of the cores form a reflector module, and the reflector modules are stacked. Forming the reflecting portion.         The neutron capture treatment system according to item 4 of the scope of patent application, wherein the material of the core, the top plate, the bottom plate and the side plate is a low neutron absorption cross section and a low activation material, and the core, the top plate, the bottom plate and The proportion of the total material volume of the side plate to the volume of the reflector material is less than 10%.         According to the neutron capture therapy system described in item 5 of the patent application scope, the material of the reflector is lead, and the material of the core, top plate, bottom plate, and side plate is aluminum alloy or lead-antimony alloy.         A neutron capture therapy system includes: an accelerator for generating a charged particle beam; a neutron generating section for generating a neutron beam after irradiation with the charged particle beam; and a beam shaper for shaping the neutron beam; wherein The beam shaping body includes a retarder and a reflecting part covering the outer periphery of the retarder. The neutron generating part generates neutrons after being irradiated with a charged particle beam, and the retarder will generate the neutron from the neutron generating part. The generated neutron is decelerated to a preset energy spectrum, and the reflection portion guides the deviated neutrons to increase the intensity of the neutron in the preset energy spectrum. The reflection portion is also covered with a shielding portion on the outer periphery, and the shielding portion The support includes a support capable of supporting the reflector and a shield provided in the support.         The neutron capture therapy system according to item 7 in the scope of the patent application, wherein the shielding unit includes a plurality of cells, and each of the cells forms a core with an accommodation space, and the shield is provided on the In the accommodating space of the core, a plurality of cores are connected to form the support, the support is an integrally formed structure, and the shield material is cast and disposed in the accommodating space of the core.         The neutron capture therapy system according to item 7 of the scope of patent application, wherein the support is formed by a predetermined number of cores connected to each other, and an outer side of the support is provided with a top plate and a bottom plate opposite to the support plate, The side plates connected and surrounded on the periphery of the core, the specified number of connected cores, the shields, the top plate, the bottom plate, and the side plates provided in the cores form a shield module, and the shield modules are stacked to form the shield The material of the shield body is lead, and the materials of the core, top plate, bottom plate, and side plate are low neutron absorption cross sections and low activation materials. The total volume of the material of the core, top plate, bottom plate, and side plate accounts for the The proportion of the material volume of the reflector is less than 10%.         The neutron capture treatment system according to item 7 of the scope of the patent application, wherein the reflection part includes a reflector capable of guiding deviated neutrons back to increase the neutron intensity within a preset energy spectrum and capable of forming the reflector. Supporting brace.