CN116759131A - Adjustable beam shaping device, assembly method and application - Google Patents

Abstract

The application provides an adjustable beam shaping device, an assembly method and application, wherein the adjustable beam shaping device comprises the following components: the proton beam device comprises a reflector with a containing cavity, a proton beam channel, a target material and a slowing core body, wherein the axial part of the proton beam channel penetrates through the reflector, and the target material and the slowing core body are arranged in the containing cavity; a collimator is axially embedded at one end of the reflector, which is far away from the proton beam channel; the slowing core is positioned at one end of the proton beam channel extending into the reflector; the moderating core is composed of a plurality of base cores and a plurality of adjusting cores to moderate the high-energy neutron beam into a neutron beam energy range of lower energy, or the moderating core is composed of a plurality of base cores to moderate the high-energy neutron beam into an epithermal neutron energy range. According to the application, aiming at different tumor cases, more accurate neutron treatment can be provided, and the applicability to different tumor cells is improved.

Description

Adjustable beam shaping device, assembly method and application

Technical Field

The application relates to the technical field of boron neutron capture treatment, in particular to an adjustable beam shaping device, an assembly method and application.

Background

The principle of boron neutron capture therapy (Boron Neutron Capture Therapy, BNCT) is to destroy tumor cells by nuclear reactions occurring in the tumor cells by first applying a composition comprising ¹⁰ The compound of B is introduced into the patient due to thisThe seed compound has strong affinity with tumor cells, and can be rapidly gathered in tumor cells after entering the body, but has small distribution in other normal tissues, and then neutron beam is used for irradiating tumor part to make neutrons and tumor cells gathered in tumor cells ¹⁰ B is subjected to a nuclear reaction, and the reaction product is purified, ¹⁰ b capturing neutrons to generate an unstable composite core ¹¹ B， ¹¹ B spontaneously splits into an alpha particle with a kinetic energy of 1.78MeV and an alpha particle with a kinetic energy of 1.01MeV ⁷ Li recoil atomic nucleus (reaction section 6.3%); or an alpha particle with a kinetic energy of 1.47MeV and a kinetic energy of 0.84MeV ⁷ Li recoil the nuclei and emitted a photon with an energy of 0.48MeV (93.7% of the reaction cross section), ¹¹ b spontaneously splits into alpha particles and alpha particles by the following two reaction channels ⁷ Li recoil atomic nucleus, its reaction formula is as follows:

¹⁰ B+n _th → ¹¹ B→ ⁷ Li（1.01MeV）+4He（1.78MeV） 6.3%

¹⁰ B+n _th → ¹¹ B→ ⁷ Li（0.84MeV）+4He（1.47MeV）+γ（0.48MeV） 93.7%

alpha particles of the reaction product of the process ⁷ The Li recoil nucleus has the characteristics of high linear energy conversion (Linear energy transfer, LET) and low oxygen enhancement ratio, can kill tumor cells with high selectivity and high strength, and simultaneously reduces the damage to surrounding normal tissues to the greatest extent.

In fact, neutrons generated by accelerator neutron sources or reactor neutron sources cannot be used directly in the treatment of patients, especially boron neutron capture therapy (accelerator-based neutron source boron neutron capture therapy, AB-BNCT) based on accelerator neutron sources, typically using the reaction of protons with lithium or neutrons generated with beryllium. The emitted neutrons have higher energy, are easy to directly penetrate the human body, and cannot achieve the expected treatment effect. Therefore, after the neutron beam is obtained through the neutron source target, the neutron beam is required to be subjected to slowing down and collimation through a beam shaping device (Beam shaping assembly, BSA) until the neutron beam meets the treatment standard, so that the patient can be irradiated.

The current design standard of the existing beam shaping system mainly refers to IAEA-TECDOC-1223 published in 2001 of the International atomic energy agency and Advances in Boron Neutron Capture Therapy published in 2023, and both documents suggest the use of neutrons in the energy region of 0.5keV to 10keV as epithermal neutrons. However, some scholars believe that neutrons slightly above 10keV may also be used in the treatment of deep tumors, for example 16keV and below.

Chinese patent publication No. CN115120893a discloses a boron neutron capture therapeutic beam shaping device, comprising: a particle beam channel part, a beam shaping part, an activation suppression part, a beam shielding part and a beam extraction part; the beam shaping part is used for shaping an initial neutron source generated by the target material so as to obtain an epithermal neutron beam which meets IAEA indexes and can be used for neutron capture treatment.

However, the retarder included in the beam shaping portion in the above prior art has a main function of reducing the high-energy neutron beam into an epithermal neutron beam for effective treatment, so as to effectively treat glioma, melanoma, recurrent head and neck tumor and the like, and has a technical defect that an initial neutron source is difficult to shape to obtain a low-energy neutron beam, so that the superficial tumor cannot be treated, and the applicability of the beam shaping device for boron neutron capture treatment on different tumor cells is limited.

Therefore, it is important to solve the technical problem of how to provide a beam shaper for obtaining both low-energy neutron beams and high-energy neutron beams.

Disclosure of Invention

The application aims to provide an adjustable beam shaping device, an assembly method and application, which are used for solving a plurality of defects of the beam shaping device in the prior art, and particularly for realizing treatment of low-energy neutron beams or high-energy neutron beams selected for different tumors, thereby improving the applicability of the beam shaping device to different tumor cells.

In order to achieve the above object, in a first aspect, the present application provides an adjustable beam shaping device, including: the proton beam device comprises a reflector with a containing cavity, a proton beam channel, a target material and a slowing core body, wherein the axial part of the proton beam channel penetrates through the reflector, and the target material and the slowing core body are arranged in the containing cavity;

a collimator is axially embedded at one end of the reflector, which is far away from the proton beam channel;

the slowing core is positioned at one end of the proton beam channel extending into the reflector;

the moderating core is composed of a plurality of base cores and a plurality of adjusting cores to moderate the high-energy neutron beam into a neutron beam energy range of lower energy, or the moderating core is composed of a plurality of base cores to moderate the high-energy neutron beam into an epithermal neutron energy range.

According to the application, in some aspects, the moderating core is composed of a total of 2/3 of the base core and the moderating core to moderate the high energy neutron beam into a lower energy neutron beam energy range, the total thickness of the base core and the moderating core being 21-33cm or 22-33cm.

According to the present application, in some aspects, the moderating core is composed of one of the base cores and one of the conditioning cores;

the thickness of the substrate core body is 20-27cm, and the thickness of the adjusting core body is 1-6cm.

According to the application, in some aspects, the moderating core is composed of one said base core and two said tuning cores;

the thickness of the substrate core body is 20-27cm, the total thickness of the two adjusting core bodies is 2-6cm, and the minimum thickness of the single adjusting core body is 1cm.

According to the present application, in some aspects, the moderating core is composed of two of the base cores and one of the adjusting cores;

the thickness of the adjusting core body is 1-6cm;

the total thickness of the two substrate cores is 21-27cm, wherein at least one substrate core with the thickness of 20cm is arranged, and the thickness of the other substrate core is 1-7cm.

According to the present application, in some aspects, the moderating core is composed of not more than four of the base cores to moderate the high-energy neutron beam into the epithermal neutron energy range, wherein at least one of the base cores having a thickness of 20cm is present, the other three of the base cores having a thickness of 1cm at a minimum, and the total thickness of four of the base cores is 23-33cm.

According to some embodiments of the present application, the base core and the adjustment core are disposed in the accommodating cavity in sequence along the extending direction of the proton beam channel, and the base core is axially abutted against the adjustment core.

According to the present application, in some embodiments, the base core material is magnesium fluoride and the conditioning core material is polyethylene or magnesium fluoride or a combination of polyethylene and magnesium fluoride.

According to the application, in some aspects, the collimator is configured as a tapered bore that tapers in an axial direction;

the inner diameter of an expansion part formed at one end of the conical hole close to the slowing core body is 28-38cm, the inner diameter of an opening part formed at one end of the expansion part of the conical Kong Fanxiang is 10-24cm, and the axial length of the conical hole is 10 or 14cm.

According to the application, in some aspects, the collimator is configured as a cylindrical through-hole that is axially through;

the inner diameter of the through hole is 10-24cm, and the axial length of the through hole is 10 or 14cm.

According to the present application, in some aspects, the adjustable beam shaping device further includes: the device comprises a slowing core, a collimator, a filtering unit, a telescopic tube, a cooling unit and a driving unit, wherein the filtering unit is formed between the slowing core and the collimator, the telescopic tube is formed in the proton beam channel and is provided with the target, the cooling unit is circumferentially arranged around the target to cool the target, and the driving unit is used for driving the telescopic tube to axially stretch and retract so as to drive the target to abut against the slowing core.

According to the application, in some aspects, the filter unit is configured as a thermal neutron filter and/or a gamma ray filter.

According to the present application, in some aspects, the reflector includes: the back reflector is circumferentially arranged around the slowing core body and the filtering unit, axially abuts against the side reflector, the accommodating cavity is formed by surrounding the side reflector and the back reflector, and the standby core body is arranged in the accommodating cavity and axially abuts against the slowing core body;

the back reflector and the standby core are axially sleeved on the outer side of the proton beam channel in sequence.

In a second aspect, the present application provides a method for assembling an adjustable beam shaping device as disclosed in any one of the preceding applications, comprising the steps of:

step S1, extracting neutron beams in different energy ranges according to different neutron capture treatment requirements, and correspondingly selecting a plurality of substrate cores and a plurality of adjustment cores of different materials or a plurality of substrate cores;

s2, arranging and combining a plurality of substrate cores and a plurality of adjustment cores side by side to form a slowing core, or arranging and combining a plurality of substrate cores to form a slowing core;

s3, sequentially placing the standby core, the slowing core, the filtering unit and the collimator into the side reflector along the axial direction, enabling the standby core to tightly lean against the slowing core, and connecting the back reflector to one side, close to the standby core, of the side reflector;

and S4, enabling the proton beam channel to sequentially penetrate through the back reflector and the standby core body along the axial direction, and driving the telescopic pipe to axially stretch in the proton beam channel through the driving unit so as to drive the target to abut against the slowing core body, so that the adjustable beam shaping device is finally formed.

In a third aspect, the present application provides an adjustable beam shaping device as disclosed in any one of the preceding applications, wherein the adjustable beam shaping device is applied to an accelerator boron neutron capture experimental device.

The adjustable beam shaping device, the assembly method and the application have the following beneficial technical effects: the high-current charged particle beam generated by a charged particle linear accelerator (not shown) passes through a proton beam channel to bombard a target material to be consumed into high-energy neutron beam, and then the high-energy neutron beam loses part of energy through interaction between a slowing core body and the high-energy neutron beam, so that the high-energy neutron beam is slowed down to a neutron beam energy range with lower energy, neutron beams with lower energy are obtained, and the superficial tumor can be effectively treated; or the tumor is slowed down to an epithermal neutron energy range to obtain an epithermal neutron beam, so that brain glioma, melanoma, head and neck recurrent tumor and the like can be effectively treated, further different tumor cases can be treated, more accurate neutron treatment is provided, and the applicability to different tumor cells is improved.

Drawings

FIG. 1 is a block diagram of an adjustable beam shaping device according to the present application, wherein a slowing core is composed of a plurality of base cores;

FIG. 2 is a schematic diagram of an adjustable beam shaping device according to the present application, wherein a slowing core is composed of a plurality of base cores, and a plurality of spare cores are filled in a receiving cavity;

FIG. 3 is a schematic diagram of an adjustable beam shaping device according to the present application, wherein a slowing core is composed of a base core and a plurality of adjustment cores, and a plurality of standby cores are filled in a receiving cavity;

FIG. 4 is an energy spectrum of an outgoing neutron beam of FIG. 3 using a moderating core having a total thickness of 24 cm;

FIG. 5 is a plot of the dose rate distribution of the neutron beam exiting FIG. 4 in a soft tissue phantom, where Tumor is Tumor tissue and Nomal is normal tissue;

FIG. 6 is an energy spectrum of an outgoing neutron beam using a moderated core of total thickness 20-32cm in FIG. 1 or FIG. 2;

FIG. 7 is a plot of the dose rate distribution of the neutron beam exiting FIG. 6 in a soft tissue phantom, where Tumor is Tumor tissue and Nomal is normal tissue;

fig. 8 is a flowchart of an assembling method of the adjustable beam shaping device provided by the application.

Detailed Description

In order to make the objects, technical solutions and advantages of the technical solutions of the present disclosure more clear, the technical solutions of the embodiments of the present disclosure will be clearly and completely described below with reference to the accompanying drawings of specific embodiments of the present disclosure. Like reference numerals in the drawings denote like parts. It should be noted that the described embodiments are some, but not all embodiments of the present disclosure. All other embodiments, which can be made by one of ordinary skill in the art without the need for inventive faculty, are within the scope of the present disclosure, based on the described embodiments of the present disclosure.

Unless defined otherwise, technical or scientific terms used herein should be given the ordinary meaning as understood by one of ordinary skill in the art to which this application belongs. The terms "first," "second," and the like in the description and in the claims, are not used for any order, quantity, or importance, but are used for distinguishing between different elements. The word "comprising" or "comprises", and the like, means that elements or items preceding the word are included in the element or item listed after the word and equivalents thereof, but does not exclude other elements or items. "inner", "outer", "upper", "lower", "far", "near", "front", "rear", etc. are used merely to denote relative positional relationships, which may also change accordingly when the absolute position of the object being described changes. The drawings in this disclosure are not necessarily to scale, and the specific dimensions and numbers of individual structures may be determined according to actual needs. The drawings described in the present disclosure are only schematic in structure.

During all embodiments of the application, it should be noted that: the epithermal neutron beam mentioned in the present application is an epithermal neutron energy range between 0.5eV and 10keV and the average energy is greater than 1keV and less than 10keV, and the lower energy neutron beam mentioned in the present application is a neutron beam energy range with the average energy below 1keV.

Please refer to fig. 1-8, which illustrate an embodiment of an adjustable beam shaping device, an assembly method and an application of the present application.

In the existing boron neutron capture treatment system driven by a linear accelerator, a neutron irradiation method is to accelerate a charged particle beam through the linear accelerator, the charged particle beam is accelerated to energy sufficient to overcome the coulomb repulsion of a target material atomic nucleus, a target material is bombarded, a nuclear reaction is carried out to generate a high-energy neutron beam, the high-energy neutron beam passes through a specific beam shaping device, then the shaping and the moderating of the epithermal neutron energy range are carried out, an epithermal neutron beam is obtained, and finally the neutron beam is concentrated and converged through a collimator, and irradiates a target region of a human body. Compared with the prior art, the adjustable beam shaping device 100 provided by the implementation can provide accurate neutron treatment for different tumor cases. For example, by adopting the moderating core 40 as shown in fig. 3 composed of the plurality of base cores 41 and the plurality of adjusting cores 42, the moderating core 40 moderates the high-energy neutron beam to a lower-energy neutron beam energy range to obtain a lower-energy neutron beam, thereby realizing effective treatment of the superficial tumor; or by adopting the moderating core body 40 which is composed of a plurality of substrate core bodies 41 and is shown in fig. 1 or 2, the moderating core body 40 moderates the high-energy neutron beam current to the epithermal neutron energy range so as to obtain the epithermal neutron beam, thereby effectively treating glioma, melanoma, recurrent tumor of the head and the neck, and the like, and improving the applicability to different tumor cells.

As shown in fig. 1 to 7, the adjustable beam shaping device 100 includes: a reflector 10 having a receiving cavity 11, a proton beam passage 20 passing through the reflector 10 in an axial direction (i.e., in a direction indicated by a central axis W in fig. 1), a target 30 being provided in the proton beam passage 20, and a slowing core 40 being provided in the receiving cavity 11; an end of the reflector 10 remote from the proton beam passage 20 is axially embedded with a collimator 50; the moderating core 40 is located at one end of the proton beam passage 20 extending into the reflector 10; the moderating core 40 is composed of a plurality of base cores 41 and a plurality of adjusting cores 42 to moderate the high-energy neutron beam into a neutron beam energy range of lower energy, or the moderating core 40 is composed of a plurality of base cores 41 to moderate the high-energy neutron beam into an epithermal neutron energy range. The high-current charged particle beam generated by the charged particle linear accelerator (not shown) passes through the proton beam channel 20 to bombard the target 30, is consumed as high-energy neutron beam, and then interacts with the high-energy neutron beam through the slowing core 40, so that part of energy is lost by the high-energy neutron beam, and the high-energy neutron beam is slowed down to a neutron beam energy range with lower energy, so that a neutron beam with lower energy is obtained; or it is slowed down to the epithermal neutron energy range to obtain an epithermal neutron beam, which can be collimated by collimator 50 and used to emit the neutron beam to increase neutron flux. In practical use, by adopting the moderating core 40 as shown in fig. 3, which is composed of a plurality of base cores 41 and a plurality of adjusting cores 42, the moderating core 40 moderates the high-energy neutron beam to a neutron beam energy range with lower energy so as to obtain a neutron beam with lower energy, thereby realizing effective treatment of superficial tumors; further, by using the moderating core 40 as shown in fig. 1 or 2 constituted by a plurality of base cores 41, the moderating core 40 moderates the high-energy neutron beam to the epithermal neutron energy range to obtain the epithermal neutron beam, and thereby, brain glioma, melanoma, head and neck recurrent tumor, and the like can be effectively treated. And further, the method can provide more accurate neutron treatment aiming at different tumor cases, and improves the applicability to different tumor cells.

It should be noted that, the material of the target 30 may be a lithium target or a beryllium target, and the high-energy neutron beam is generated by bombarding the lithium target or the beryllium target with a commonly used high-current particle beam. The material of the reflector 10 is preferably lead (Pb). In addition, the charged particle linear accelerator (not shown) may be an electrostatic linear accelerator, a cyclotron linear accelerator, a synchrotron, a cyclotron+synchrotron, a linear accelerator, a laser-driven linear accelerator, or the like.

The material of the base core 41 may be one or more of magnesium fluoride, aluminum fluoride, calcium fluoride, aluminum, etc., and the material of the base core 41 is preferably magnesium fluoride (MgF) ₂ ) The method comprises the steps of carrying out a first treatment on the surface of the The material of the adjusting core 42 may be one or more of magnesium fluoride, polyethylene, polytetrafluoroethylene, beryllium oxide, heavy water, etc., and the material of the adjusting core 42 is preferably Polyethylene (PE).

As shown in fig. 3, when it is desired to obtain a neutron beam of lower energy, in particular, the moderating core 40 is composed of a total number of base cores 41 and moderating cores 42 of 2/3 to moderate the high-energy neutron beam into a neutron beam energy range of lower energy, and the total thickness of the base cores 41 and moderating cores 42 is 21-33cm or 22-33cm. The material of the base core 41 is preferably magnesium fluoride, and the material of the adjustment core 42 is preferably polyethylene.

As shown in fig. 4, curve 1"24mf" means: the moderating core 40 is composed of one or two or three base cores 41 having a total thickness of 24 cm; curve 2"4pe+20mf" means: the moderating core 40 is composed of an adjusting core 42 and a base core 41 which are arranged in the accommodating cavity 11 in sequence along the extending direction of the proton beam channel 20, a base core 41 with the thickness of 20cm and one or two adjusting cores 42 with the total thickness of 4 cm; curve 3"20mf+4pe" means: the slowing core 40 is composed of a base core 41 and an adjusting core 42 which are sequentially arranged in the accommodating cavity 11 along the extending direction of the proton beam channel 20, wherein the base core 41 has a thickness of 20cm and one or two adjusting cores 42 have a total thickness of 4 cm; as shown in fig. 4 in combination with these 3 curves, when the substrate core 41 having the same thickness (i.e., 24 cm) is used, the high-energy neutron component can be significantly reduced by using the adjustment core 42 instead of a part of the substrate core 41 having the same thickness, and the substrate core 41 and the adjustment core 42 disposed in the housing chamber 11 in the extending direction of the proton beam passage 20 are disposed in this order, so that the effect of reducing the high-energy neutron component is better. Thus, it is preferable that the moderating core 40 is composed of a plurality of base cores 41 and a plurality of adjusting cores 42 to enhance the effect of the moderating core 40 in reducing the high-energy neutron component. The base core 41 and the adjusting core 42 are disposed in the accommodating cavity 11 in sequence along the extending direction of the proton beam channel 20, and the base core 41 and the adjusting core 42 are axially abutted.

After the strong-current charged particle beam passes through the proton beam channel 20 to bombard the target 30 to form a high-energy neutron beam, the high-energy neutron beam is firstly incident on the substrate core 41 made of magnesium fluoride, the high-energy neutron beam can be slowed down to about 10keV energy through the magnesium fluoride, so that the high-energy neutrons with about 10keV energy or the medium-energy neutrons with lower energy passing through the substrate core 41 are reduced, the high-energy neutrons with higher than 10keV are incident on the adjustment core 42, the neutrons with about 10keV or the neutrons with lower energy can be rapidly slowed down through the adjustment core 42 made of polyethylene, and the neutrons with lower energy are emitted by the collimator 50, so that the effective treatment of the superficial tumor can be realized.

Further, as shown in fig. 3 and 5, a filter unit 60 is formed between the moderating core 40 and the collimator 50, and the filter unit 60 is configured as a thermal neutron filter 61 and/or a gamma ray filter 62. The material of the thermal neutron filter 61 is preferably lithium fluoride (LiF), and the material of the gamma ray filter 62 is preferably lead (Pb).

The dose rate distribution of the neutron beam in the soft tissue phantom is shown in fig. 5, wherein Tumor is Tumor tissue, nomal is normal tissue, and the normal tissue tolerates equivalent photon dose of 12.5Gy and the Tumor lethal dose is 30 Gy. Curve 1 "Tumor_22MF, 0.3LIF,0.3Pb" means: the moderating core 40 is composed of two base cores 41 having a total thickness of 22cm, and the filtering unit 60 is configured of one thermal neutron filter 61 having a thickness of 0.3cm and one gamma ray filter 62 having a thickness of 0.3 cm; curve 2 "Tumor_22MF, 0.6Pb" means: the moderating core 40 is composed of two base cores 41 having a total thickness of 22cm, and the filtering unit 60 is configured as one or two gamma ray filters 62 having a total thickness of 0.6 cm; when the moderating core 40 is constituted by two base cores 41 having a total thickness of 22cm, the thermal neutron filter 61 is removed and replaced with the gamma ray filter 62 having the same thickness as that thereof, that is, when curve 1 is changed to curve 2, the peak of the curve 1 dose rate curve is changed from a depth of 2.20cm to 1.95cm and the peak is increased by 6%, and therefore, the treatment of the shallow tumor is facilitated by both of the above-mentioned changes.

Further, as shown in FIG. 5, curve 3 "Tumor_20MF, 2PE,0.6Pb" means: the moderating core 40 is composed of two base cores 41 having a total thickness of 20cm and one or two adjusting cores 42 having a total thickness of 2cm, and the filtering unit 60 is configured as two gamma ray filters 62 having a total thickness of 0.6cm, the peak of the dose rate curve being 0.85cm in depth; curve 4 "Tumor_20MF, 4PE,0.6Pb" means: the moderating core 40 is composed of two base cores 41 having a total thickness of 20cm and one or two adjusting cores 42 having a total thickness of 4cm, and the filtering unit 60 is configured as two gamma ray filters 62 having a total thickness of 0.6cm, the peak of the dose rate curve being 0.35cm in depth; curve 5 "Tumor_20MF, 6PE,0.6Pb" means: the moderating core 40 is composed of two base cores 41 having a total thickness of 20cm and one or two adjusting cores 42 having a total thickness of 6cm, and the filtering unit 60 is configured as two gamma ray filters 62 having a total thickness of 0.6cm, with a dose rate curve peak having a depth of 0.25 cm; by these 5 curves, it is shown that tumor treatment can be accomplished within the tolerable dose of normal tissue (i.e., 12.5 Gy) by adjusting the thickness of the core 42 to within 6cm. It can be seen that the combination of the base core 41 and the adjustment core 42 can adjust the depth of the peak of the dose rate curve.

Further, in the present embodiment, experiments by the research and development personnel prove that the total thickness of the base core 41 and the adjustment core 42 is 21-33cm or 22-33cm, and the slowing core 40 is composed of the total number of 2/3 of the base cores 41 and the adjustment cores 42, wherein at least one base core 41 with a thickness of preferably 20cm and one adjustment core 42 with a thickness of 1-6cm are present, so that the best effect can be achieved.

When a lower energy neutron beam is desired, an example of what the moderating core 40 may constitute is as follows: the slowing core 40 can be composed of a base core 41 and an adjusting core 42, wherein the thickness of the base core 41 is 20-27cm, and the thickness of the adjusting core 42 is 1-6cm; alternatively, the slowing core 40 is composed of a base core 41 and two adjusting cores 42, wherein the thickness of the base core 41 is 20-27cm, the total thickness of the two adjusting cores 42 is 2-6cm, and the minimum thickness of the single adjusting core 42 is 1cm; alternatively, the moderating core 40 is composed of two base cores 41 and one regulating core 42, and the thickness of the regulating core 42 is 1-6cm, the total thickness of the two base cores 41 is 21-27cm, one of the base cores 41 is 20cm, and the other base core 41 is 1-7cm.

As shown in fig. 1 and 2, when it is desired to obtain an epithermal neutron beam, in particular, the moderating core 40 is composed of no more than four base cores 41 to moderate the high-energy neutron beam into an epithermal neutron energy range, in which there is at least one base of 20cm in thicknessThe thickness of the other three substrate cores 41 of the core 41 is 1cm, the total thickness of the four substrate cores 41 is 23-33cm, and the substrate cores 41 are mutually and axially abutted. The material of the base core 41 is magnesium fluoride (MgF) ₂ ) The filter unit 60 is formed between the moderating core 40 and the collimator 50, and the filter unit 60 is configured as a thermal neutron filter 61 and a gamma ray filter 62. The material of the thermal neutron filter 61 is preferably lithium fluoride (LiF), and the material of the gamma ray filter 62 is preferably lead (Pb).

Further, as shown in fig. 6 and 7, wherein Tumor is Tumor tissue, nomal is normal tissue, and the normal tissue tolerates an equivalent photon dose of 12.5Gy, and the Tumor lethal dose is 30 Gy. Curve 1"20mf" means: the moderating core 40 is composed of a base core 41 having a thickness of 20 cm; curve 2"24mf" means: the moderating core 40 is constituted by a base core 41 having a total thickness of 24cm and not more than four; curve 3"28mf" means: the moderating core 40 is constituted by a base core 41 having a total thickness of 28cm and not more than four; curve 4"32mf" means: the moderating core 40 is constituted by a base core 41 having a total thickness of 32cm and not more than four; by using a moderation core 40 composed of one or not more than four base cores 41 having a thickness of 20-32cm, the peak position of the emitted neutron spectrum can be reduced from 16keV to 1keV in combination with these 4 curves and as shown in fig. 6 and 7.

In the present embodiment, when the slowing-down core 40 composed of the base cores 41 having a total thickness of 20-28cm and not more than four is calculated by the developer, the neutron beam treatment depth gradually increases from 4.8cm to 5.6cm; the treatment depth was maintained at 5.6cm when using a moderating core 40 composed of a base core 41 having a total thickness of 28-32cm and not more than four. Wherein there is at least one base core 41 having a thickness of 20cm, and the other three base cores 41 have a thickness of at least 1cm.

When an epithermal neutron beam is desired, an example of a composition of the moderating core 40 is as follows: the moderating core 40 is composed of a base core 41 having a thickness of 20 cm; alternatively, the slowing core 40 is composed of two axially abutted base cores 41, wherein the thickness of one base core 41 is 20cm, and the thickness of the other base core 41 is 1-13cm; alternatively, the slowing core 40 is composed of three axially abutted base cores 41, wherein the thickness of one base core 41 is 20cm, and the total thickness of the other two base cores 41 is 2-13cm; alternatively, the moderating core 40 is composed of four axially abutted base cores 41, wherein one base core 41 has a thickness of 20cm, and the other three base cores 41 have a total thickness of 3-13cm.

As shown in fig. 1 to 3, the adjustable beam shaping device 100 further includes: the apparatus includes a filter unit 60 formed between the slowing core 40 and the collimator 50, a bellows 70 formed in the proton beam passage 20 and configured with the target 30, a cooling unit (not shown) circumferentially surrounding the target 30 to cool the target 30, and a driving unit (not shown) driving the bellows 70 to expand and contract in an axial direction to drive the target 30 to abut against the slowing core 40. The reflector 10 includes: the side reflector 12 is circumferentially arranged around the slowing core 40 and the filtering unit 60, the back reflector 13 is axially abutted against the side reflector 10, the accommodating cavity 11 is formed by surrounding the side reflector 12 and the back reflector 13, and the standby core 101 is arranged in the accommodating cavity 11 and axially abutted against the slowing core 40; the back reflector 13 and the spare core 101 are axially sleeved outside the proton beam channel 20 in sequence. Preferably, the material of the spare core 101 is lead (Pb).

In the above process of obtaining the neutron beam or the epithermal neutron beam with lower energy, the moderating core 40 is formed by a plurality of base cores 41 and a plurality of adjusting cores 42, or the moderating core 40 is formed by a plurality of base cores 41, when the total thickness of the plurality of base cores 41 and the plurality of adjusting cores 42 or the total thickness of the plurality of base cores 41 is smaller than the axial length of the accommodating cavity 11, the plurality of spare cores 101 can be filled between the base cores 41 and the target 30, so that the base cores 41 and the adjusting cores 42 are axially abutted, or the plurality of base cores 41 are axially abutted. And the back reflector 13 and the spare core 101 are configured with a connection hole (not shown) for the proton beam channel 20 to penetrate, so that the proton beam channel 20 axially extends into the connection hole, and the driving unit drives the telescopic tube 70 to axially stretch and retract to drive the target 30 to abut against the slowing core 40.

In the present embodiment, preferably, the collimator 50 is configured with a tapered hole 51 that is tapered in the axial direction; the inner diameter of the expansion portion 511 formed at the end of the tapered hole 51 near the moderating core 40 is 28-38cm, the inner diameter of the opening portion 512 formed at the end of the tapered hole 51 opposite to the expansion portion 511 is 10-24cm, and the axial length of the tapered hole 51 is 10 or 14cm. Preferably, the material of the collimator 50 is composed of polyethylene mixed with lithium fluoride to achieve moderation and absorption of neutrons. The inner diameters of the expansion portion 511 and the opening portion 512 may be set according to the specific tumor condition, and different inner diameters of the expansion portion 511 and the opening portion 512 are used for different tumor patients. The smaller the inner diameter size of the opening 512, the larger the inner diameter size of the expansion 511, which can enhance neutron flux; the larger the inner diameter of the opening 512, the smaller the inner diameter of the expansion 511, which reduces neutron leakage and prevents damage to normal tissue.

For example, in some embodiments, collimator 50 is configured as an axially-extending cylindrical through-hole (not shown); the inner diameter of the through hole is 10-24cm, and the axial length of the through hole is 10 or 14cm. The inner diameter size of the through hole can be set according to specific tumor conditions, and different inner diameter sizes are adopted for different tumor patients.

The application also provides an assembly method of the adjustable beam shaping device, which is shown in the figures 1 to 8, and comprises the following steps:

step S1, extracting neutron beams in different energy ranges according to different neutron capture treatment requirements, and correspondingly selecting a plurality of substrate cores 41 and a plurality of adjustment cores 42 or a plurality of substrate cores 41 of different materials; when neutron capture treatment is required for superficial tumors, the total number of the substrate cores 41 and the adjustment cores 42 is 2/3, the total thickness of the substrate cores 41 and the adjustment cores 42 is 21-33cm or 22-33cm, at least one substrate core 41 with the thickness of preferably 20cm and one adjustment core 42 with the thickness of 1-6cm are present, the material of the substrate core 41 is preferably magnesium fluoride, and the material of the adjustment core 42 is preferably polyethylene; or when neutron capture treatment is required to be carried out on brain glioma, melanoma, head and neck recurrent tumor and the like, the number of the correspondingly selected substrate cores 41 is not more than four, the total thickness of the four substrate cores 41 is 23-33cm, at least one substrate core 41 with the thickness of 20cm is arranged, the thickness of the other three substrate cores 41 is 1cm at the minimum, and the material of the substrate cores 41 is preferably magnesium fluoride;

step S2, arranging and combining a plurality of substrate cores 41 and a plurality of adjustment cores 42 side by side to form a moderating core 40, or arranging and combining a plurality of substrate cores 41 to form a moderating core 40; the total number of the substrate cores 41 and the adjusting cores 42 is 2/3, and the substrate cores 41 and the adjusting cores 42 are sequentially arranged in the accommodating cavity 11 along the extending direction of the proton beam channel 20 to form a slowing core 40; or no more than four base cores 41 constitute the moderating core 40;

step S3, sequentially placing the standby core 101, the slowing core 40, the filtering unit 60 and the collimator 50 in the side reflector 12 along the axial direction, enabling the standby core 101 to abut against the slowing core 40, and connecting the back reflector 13 to one side of the side reflector 12 close to the standby core 101;

in step S4, the proton beam channel 20 sequentially penetrates through the back reflector 13 and the spare core 101 in the axial direction, and then the driving unit (not shown) drives the telescopic tube 70 to axially expand and contract in the proton beam channel 20 to drive the target 30 to abut against the slowing core 40, so as to finally form the adjustable beam shaping device 100.

Based on the technical solution of the adjustable beam shaping device 100 disclosed in the foregoing embodiment, the adjustable beam shaping device 100 is applied to an accelerator boron neutron capture experimental device (BNCT) (not shown), so that the accelerator boron neutron capture experimental device (BNCT) configured with the adjustable beam shaping device 100 can selectively switch the structural mode of the slowing-down core 40 for different tumor cases, for example, by adopting the slowing-down core 40 as shown in fig. 3 composed of a plurality of base cores 41 and a plurality of adjusting cores 42, the high-energy neutron beam is slowed down to a neutron beam energy range with lower energy by the slowing-down core 40, so as to obtain a neutron beam with lower energy, thereby realizing effective treatment of superficial tumors; or by adopting the moderating core body 40 which is composed of a plurality of substrate core bodies 41 and is shown in fig. 1 or 2, the moderating core body 40 moderates the high-energy neutron beam current to the epithermal neutron energy range so as to obtain the epithermal neutron beam, thereby effectively treating glioma, melanoma, recurrent tumor of the head and the neck, and the like, and improving the applicability to different tumor cells.

The foregoing is merely a specific embodiment of the disclosure, but the protection scope of the disclosure is not limited thereto, and any person skilled in the art can easily think about changes or substitutions within the technical scope of the disclosure, and it should be covered in the protection scope of the disclosure. Therefore, the protection scope of the present disclosure shall be subject to the protection scope of the claims.

Claims (15)

1. An adjustable beam shaping device, comprising:

the proton beam device comprises a reflector with a containing cavity, a proton beam channel, a target material and a slowing core body, wherein the axial part of the proton beam channel penetrates through the reflector, and the target material and the slowing core body are arranged in the containing cavity;

a collimator is axially embedded at one end of the reflector, which is far away from the proton beam channel;

the slowing core is positioned at one end of the proton beam channel extending into the reflector;

the moderating core is composed of a plurality of base cores and a plurality of adjusting cores to moderate the high-energy neutron beam into a neutron beam energy range of lower energy, or the moderating core is composed of a plurality of base cores to moderate the high-energy neutron beam into an epithermal neutron energy range.

2. The adjustable beam shaping device according to claim 1, wherein the moderating core is composed of the base core and the adjusting core in a total number of 2/3 to moderate the high-energy neutron beam into a neutron beam energy range of lower energy, and a total thickness of the base core and the adjusting core is 21-33cm or 22-33cm.

3. The adjustable beam shaping device according to claim 2, wherein the slowing core is composed of one of the base cores and one of the adjustment cores;

the thickness of the substrate core body is 20-27cm, and the thickness of the adjusting core body is 1-6cm.

4. The adjustable beam shaping device according to claim 2, wherein the slowing core is composed of one base core and two adjustment cores;

the thickness of the substrate core body is 20-27cm, the total thickness of the two adjusting core bodies is 2-6cm, and the minimum thickness of the single adjusting core body is 1cm.

5. The adjustable beam shaping device according to claim 2, wherein the slowing core is composed of two of the base cores and one of the adjustment cores;

the thickness of the adjusting core body is 1-6cm;

the total thickness of the two substrate cores is 21-27cm, wherein at least one substrate core with the thickness of 20cm is arranged, and the thickness of the other substrate core is 1-7cm.

6. The adjustable beam shaping device according to claim 1, wherein the moderating core is composed of no more than four of the base cores to moderate the high-energy neutron beam into the epithermal neutron energy range, wherein there is at least one of the base cores having a thickness of 20cm, the other three of the base cores having a thickness of at least 1cm, and the total thickness of four of the base cores is 23-33cm.

7. The adjustable beam shaping device according to claim 2 or 6, wherein the base core and the adjustment core are disposed in the accommodating cavity in sequence along the extending direction of the proton beam channel, and the base core is axially abutted to the adjustment core.

8. The adjustable beam shaping device according to claim 7, wherein the base core material is magnesium fluoride and the adjustment core material is polyethylene or magnesium fluoride or a combination of polyethylene and magnesium fluoride.

9. The adjustable beam shaping device according to claim 8, wherein the collimator is configured as a tapered bore that tapers in an axial direction;

the inner diameter of an expansion part formed at one end of the conical hole close to the slowing core body is 28-38cm, the inner diameter of an opening part formed at one end of the expansion part of the conical Kong Fanxiang is 10-24cm, and the axial length of the conical hole is 10 or 14cm.

10. The adjustable beam shaping device according to claim 9, wherein the collimator is configured as a cylindrical through-hole passing through in an axial direction;

the inner diameter of the through hole is 10-24cm, and the axial length of the through hole is 10 or 14cm.

11. The adjustable beam shaping device according to claim 10, further comprising: the device comprises a slowing core, a collimator, a filtering unit, a telescopic tube, a cooling unit and a driving unit, wherein the filtering unit is formed between the slowing core and the collimator, the telescopic tube is formed in the proton beam channel and is provided with the target, the cooling unit is circumferentially arranged around the target to cool the target, and the driving unit is used for driving the telescopic tube to axially stretch and retract so as to drive the target to abut against the slowing core.

12. The adjustable beam shaping device according to claim 11, wherein the filter unit is configured as a thermal neutron filter and/or a gamma ray filter.

13. The adjustable beam shaping device according to claim 12, wherein the reflector comprises: the back reflector is circumferentially arranged around the slowing core body and the filtering unit, axially abuts against the side reflector, the accommodating cavity is formed by surrounding the side reflector and the back reflector, and the standby core body is arranged in the accommodating cavity and axially abuts against the slowing core body;

the back reflector and the standby core are axially sleeved on the outer side of the proton beam channel in sequence.

14. A method of assembling an adjustable beam shaping device according to claim 13, comprising the steps of:

step S1, extracting neutron beams in different energy ranges according to different neutron capture treatment requirements, and correspondingly selecting a plurality of substrate cores and a plurality of adjustment cores of different materials or a plurality of substrate cores;

s2, arranging and combining a plurality of substrate cores and a plurality of adjustment cores side by side to form a slowing core, or arranging and combining a plurality of substrate cores to form a slowing core;

s3, sequentially placing the standby core, the slowing core, the filtering unit and the collimator into the side reflector along the axial direction, enabling the standby core to tightly lean against the slowing core, and connecting the back reflector to one side, close to the standby core, of the side reflector;

and S4, enabling the proton beam channel to sequentially penetrate through the back reflector and the standby core body along the axial direction, and driving the telescopic pipe to axially stretch in the proton beam channel through the driving unit so as to drive the target to abut against the slowing core body, so that the adjustable beam shaping device is finally formed.

15. Use of an adjustable beam shaping device according to any one of claims 1 to 13 in an accelerator boron neutron capture experimental device.