Interventional boron neutron capture therapy device

Abstract

The application belongs to the technical field of boron neutron capture therapy of tumors, and relates to an interventional boron neutron capture therapy device. The interventional boron neutron capture therapy device comprises a neutron generator, a neutron moderator and a neutron export injector. The neutron generator is used for generating neutrons by bombarding a target material with an incident high-energy particle beam. The neutron moderator is connected to the neutron generator and is used for slowing down the neutrons generated by the neutron generator into thermal neutrons and shielding gamma rays generated in the slowing down process. The neutron export injector is connected to the neutron moderator and is used for guiding and transporting the slowed-down thermal neutrons to a treatment site in a patient's body. Thus, the problem that the neutron transport scheme in the prior art cannot effectively balance neutron utilization rate, treatment depth and additional radiation damage borne by a patient can be solved.

Description

Technical Field

[0001] This invention belongs to the field of boron neutron capture therapy technology for tumors, and relates to an interventional boron neutron capture therapy device. Background Technology

[0002] Boron neutron capture therapy (BNCT) is an innovative cancer treatment technology that combines principles of nuclear physics and biomedicine to deliver targeted cancer treatment at the cellular level. Prior to BNCT treatment, patients are given a treatment containing boron-10 (… 10 B) Isotope-based drugs: After the boron-containing drug is specifically absorbed by tumor cells, the tumor is irradiated with a neutron beam. 10 B(n, α) 7 Li nuclear reactions produce alpha particles and lithium-7 ( ). 7 Li particles kill tumor cells at the cellular scale (with a range of only 5-10 μm, about the diameter of a cell), and have the core advantages of short treatment courses (1-2 treatments per course) and minimal damage to normal tissues.

[0003] Currently, most of the neutrons used in BNCT (Brain-Nutrition Therapy) come from accelerators. 7 Li(p,n) 7 The fast neutrons (10 keV-1 MeV) produced by the Be reaction can theoretically react with boron-10 ( 10 B) Isotope generation 10 B(n, α) 7 Li nuclear reactions occur, but the cross-section (probability) of the nuclear reaction is negatively correlated with the neutron energy. To increase the cross-section, the fast neutrons produced by the accelerator need to be slowed down, i.e., slowed down to thermal neutrons with energies below 0.5 eV. This increases the nuclear reaction cross-section. However, the reduced energy weakens the penetrating power of the neutrons, preventing the neutron beam from effectively irradiating deeper tumor cells, such as deep liver tumors or thoracic tumors. Therefore, current BNCT treatment uses a neutron slowing beam shaper to slow down fast neutrons into hyperthermal neutrons with energies between 0.5 eV and 10 keV. Hyperthermal neutrons have stronger penetrating power than thermal neutrons. By adjusting the hyperthermal neutron energy and utilizing the body's secondary slowing effect, hyperthermal neutrons can be converted into thermal neutrons at a specified depth. This simultaneously ensures both the nuclear reaction cross-section and the treatment depth. However, this also presents new challenges. Secondary moderation causes additional radiation damage to the patient's normal tissue cells, and the maximum penetration depth of hyperthermic neutrons is only about 5 cm, which cannot meet the needs of treating tumors in deeper locations. 7 Li(p,n) 7The fast neutrons produced by the Be reaction generate a large number of thermal neutrons during the first moderation process, which are meaningless for treating deep tumors and can cause radiation damage to the patient's surface cells. These neutrons need to be filtered out before treatment, severely reducing neutron utilization. Finally, neutron beam shapers are usually specifically designed to emit only one energy spectrum of hyperthermal neutrons. If the treatment depth needs to be changed, the entire neutron beam shaper needs to be replaced, placing a huge burden on both the treatment facility and the patient.

[0004] Therefore, given that existing boron neutron capture therapy neutron transport schemes cannot effectively balance neutron utilization, treatment depth, and additional radiation damage to patients, further technical optimization of boron neutron capture therapy methods is needed to overcome current technical challenges. Summary of the Invention

[0005] The purpose of this invention is to overcome the above-mentioned defects in the prior art and to propose an interventional boron neutron capture therapy device that can solve the problem that the neutron transport schemes in the existing boron neutron capture therapy cannot effectively balance neutron utilization, treatment depth and additional radiation damage suffered by the patient.

[0006] This invention is achieved through the following scheme:

[0007] An interventional boron neutron capture therapy device includes a neutron generator, a neutron moderator, and a neutron extraction syringe. The neutron generator is used to generate neutrons by bombarding a target material with an incident high-energy particle beam. The neutron moderator is connected to the neutron generator and is used to slow down the neutrons generated by the neutron generator into thermal neutrons and shield the gamma rays generated during the slowing process. The neutron extraction syringe is connected to the neutron moderator and is used to guide and deliver the slowed thermal neutrons to the treatment site in the patient's body.

[0008] In one possible design, the neutron extraction syringe includes:

[0009] A neutron conduit, with a high vacuum created within its lumen and a neutron super-mirror coating on its inner surface, is used to transport thermal neutrons via total internal reflection; and...

[0010] A guide needle is detachably fitted onto the outer side of the end of the neutron catheter to establish a channel for the end of the neutron catheter to enter the patient's body, so as to guide the end of the neutron catheter to the treatment site through the channel.

[0011] In one possible design, the neutron super mirror coating is formed by alternating deposition of high scattering length density materials and low scattering length density materials.

[0012] In one possible design, the high scattering length density material is one of nickel, iron, and carbon; and the low scattering length density material is one of titanium, vanadium, and aluminum.

[0013] In one possible design, the neutron conduit is configured as a rectangular tube, a circular tube, or a multi-capillary tube.

[0014] In one possible design, the cross-sectional area of ​​the inlet end of the neutron conduit is larger than the cross-sectional area of ​​the outlet end.

[0015] In one possible design, the guide needle is made of 316L medical stainless steel, acrylonitrile-butadiene-styrene, polycarbonate, or polypropylene.

[0016] In one possible design, the neutron generator includes:

[0017] The accelerator drift tube has a vacuum channel inside, which is used to guide the high-energy particle beam;

[0018] The target chamber is connected to the accelerator drift tube;

[0019] A neutron target, disposed within the target chamber, is designed to be bombarded by a high-energy particle beam to produce neutrons; and,

[0020] A cooling device is used to cool the target chamber.

[0021] In one possible design, the neutron target is made of lithium-7 or beryllium-9.

[0022] In one possible design, the neutron moderator includes:

[0023] The first moderator is wrapped around the target chamber of the neutron generator and is used to moderate neutrons;

[0024] The first reflector, which is wrapped around the first moderator, is used to reflect escaping neutrons and shield gamma rays;

[0025] A second moderator, connected to the first reflector, has a neutron conduit inside for the neutron extraction syringe, used to moderate neutrons escaping from the neutron conduit; and,

[0026] The second reflector, which is wrapped around the second moderator, is used to reflect escaping neutrons and shield gamma rays.

[0027] In one possible design, the materials of the first moderator and the second moderator are one or more of aluminum fluoride, titanium fluoride, Teflon, polyethylene and magnesium fluoride.

[0028] And / or, the materials of the first reflector and the second reflector are lead, tungsten or iron.

[0029] Compared with the prior art, the present invention has the following beneficial effects:

[0030] Using the above technical solution, a high-energy particle beam (such as protons) is emitted from the accelerator and bombards the target material inside the neutron generator. The target material undergoes a nuclear reaction (such as...). 7 Li(p,n) 7 The generator produces a large number of fast neutrons of varying energies. These high-energy fast neutrons immediately enter a neutron moderator surrounding the generator. The moderator material slows the fast neutrons down through multiple collisions with atomic nuclei, significantly reducing their energy and ultimately yielding thermal neutrons with extremely high nuclear reaction cross-sections. During this process, the neutron moderator also simultaneously shields against harmful gamma rays generated during the moderation process, preventing leakage. The moderated thermal neutrons are then guided into a neutron extraction syringe. This syringe acts as a closed conduit, directly and non-destructively guiding the thermal neutrons from inside the device to its distal outlet. During treatment, this distal outlet is precisely placed at the tumor site within the patient's body, and the thermal neutrons are directly injected into the area enriched with boron-10 (… 10 B) Within the cancer cells treated with the drug, a boron neutron capture nuclear reaction immediately occurs (B) 10 B(n, α) 7 Li), which uses the generated alpha particles and lithium nuclei to destroy cancer cells.

[0031] This enables the treatment of deep tumors, including deep-seated liver cancer, pancreatic cancer, and gliomas, expanding the clinical application scope of BNCT technology. By slowing down available neutrons into thermal neutrons and using them entirely for treatment, complex filtration is eliminated, allowing the use of lower-power neutron sources to achieve the same therapeutic dose, or shortening treatment time using equivalent neutron sources, thus reducing equipment costs. Since the slowing process is entirely completed in an external neutron moderator, direct delivery of thermal neutrons avoids damage to normal tissues from secondary gamma rays and protons generated during the slowing of hyperthermic neutrons within the body. After exiting the needle, the thermal neutrons move within a small area near the needle insertion point, causing minimal damage to tissues along their path, reducing systemic and route-related toxicity and improving treatment safety. Because the treatment depth is determined by the insertion depth of the neutron extraction syringe, the equipment structure is simplified, operating costs are reduced, and it is better suited for personalized treatment of different patients and tumor locations. Attached Figure Description

[0032] Figure 1 This is a schematic diagram of the exploded structure of the interventional boron neutron capture therapy device provided by the present invention in one embodiment.

[0033] Figure 2 This is a schematic diagram of the neutron generator in one embodiment of the interventional boron neutron capture therapy device provided by the present invention.

[0034] Figure 3 This is a schematic diagram of the neutron moderator in one embodiment of the interventional boron neutron capture therapy device provided by the present invention.

[0035] Figure 4 This is a schematic diagram of the neutron extraction syringe in one embodiment of the interventional boron neutron capture therapy device provided by the present invention.

[0036] Figure 5 This is a perspective view of the neutron catheter inserted into the guide needle in the interventional boron neutron capture therapy device provided by the present invention.

[0037] Figure 6 The diagram showing the relationship between neutron energy and nuclear reaction cross section during operation of the interventional boron neutron capture therapy device provided by this invention.

[0038] Figure 7 This is a schematic diagram illustrating the principle of neutron delivery via a neutron catheter in the interventional boron neutron capture therapy device provided by the present invention.

[0039] Figure 8 This is a cross-sectional view of one embodiment of the interventional boron neutron capture therapy device provided by the present invention.

[0040] Figure 9 This is a schematic diagram of the working principle of the interventional boron neutron capture therapy device provided by the present invention. The guide needle is inserted into the patient's body and a minimally invasive channel is established. The neutron catheter is moving towards the guide needle.

[0041] Figure 10 This is a schematic diagram of the working principle of the interventional boron neutron capture therapy device provided by the present invention. The neutron catheter is indirectly placed in the patient's body, so that thermal neutrons act on the tumor treatment site.

[0042] The reference numerals in the accompanying drawings include: 1-neutron generator, 11-accelerator drift tube, 111-large sealing ring, 112-grip plate, 113-copper tube, 114-small sealing ring, 12-neutron target, 13-target chamber, 14-cooling water pipe, 2-neutron moderator, 21-first moderator, 22-first reflector, 23-second moderator, 24-second reflector, 3-neutron extraction syringe, 31-neutron conduit, 32-guide needle, 321-open end. Detailed Implementation

[0043] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. The illustrative embodiments and descriptions of this invention are only for explaining the invention and are not intended to limit the invention:

[0044] According to specific embodiments of this disclosure, an interventional boron neutron capture therapy device is provided. Based on its structural design, it can improve neutron utilization, facilitate adjustment of treatment depth, and reduce additional radiation damage suffered by patients. Figures 1 to 10 Specific embodiments thereof are shown.

[0045] like Figures 1 to 10 As shown, the interventional boron neutron capture therapy device includes a neutron generator 1, a neutron moderator 2, and a neutron extraction syringe 3. The neutron generator 1 is used to generate neutrons by bombarding a target material with an incident high-energy particle beam. The neutron moderator 2 is connected to the neutron generator 1 and is used to slow down the neutrons generated by the neutron generator 1 into thermal neutrons and shield the gamma rays generated during the slowing process. The neutron extraction syringe 3 is connected to the neutron moderator 2 and is used to guide and deliver the slowed thermal neutrons to the treatment site in the patient's body.

[0046] Using the above technical solution, a high-energy particle beam (such as protons) is emitted from the accelerator and bombards the target material inside the neutron generator. The target material undergoes a nuclear reaction (such as...). 7 Li(p,n) 7 The generator produces a large number of fast neutrons of varying energies. These high-energy fast neutrons immediately enter a neutron moderator surrounding the generator. The moderator material slows the fast neutrons down through multiple collisions with atomic nuclei, significantly reducing their energy and ultimately yielding thermal neutrons with extremely high nuclear reaction cross-sections. During this process, the neutron moderator also simultaneously shields against harmful gamma rays generated during the moderation process, preventing leakage. The moderated thermal neutrons are then introduced into a neutron extraction syringe 3. This syringe acts as a closed conduit, guiding the thermal neutrons directly and non-destructively from inside the device to its distal outlet. During treatment, this distal outlet is precisely placed at the tumor site within the patient's body, and the thermal neutrons are directly injected into the area enriched with boron-10 (… 10 B) Within the cancer cells treated with the drug, a boron neutron capture nuclear reaction immediately occurs (B) 10 B(n, α) 7 Li), which uses the generated alpha particles and lithium nuclei to destroy cancer cells.

[0047] This enables the treatment of deep tumors, including deep-seated liver cancer, pancreatic cancer, and gliomas, expanding the clinical application scope of BNCT technology. By slowing down available neutrons into thermal neutrons and using them entirely for treatment, complex filtration is eliminated, allowing the use of lower-power neutron sources to achieve the same therapeutic dose, or shortening treatment time using equivalent neutron sources, thus reducing equipment costs. Since the slowing process is entirely completed in an external neutron moderator, direct delivery of thermal neutrons avoids damage to normal tissues from secondary gamma rays and protons generated by the slowing of hyperthermic neutrons within the body. After exiting the needle, the thermal neutrons move within a small area near the needle insertion point, causing minimal damage to tissues along their path, reducing systemic and route-related toxicity and improving treatment safety. Because the treatment depth is determined by the insertion depth of the neutron extraction syringe 3, the equipment structure is simplified, operating costs are reduced, and it is better suited for personalized treatment of different patients and tumor locations.

[0048] It should be noted that directional terms such as "inner" and "outer" refer to "inner" and "outer" relative to the outline of the component. "Inner" refers to the direction towards the inside of the component, and "outer" refers to the direction away from it. Furthermore, terms such as "first" and "second" are used to distinguish one element from another and do not indicate sequence or importance. Moreover, in the following descriptions with accompanying drawings, the same reference numerals in different drawings represent the same element. The phrase "and / or" in the text refers to A and / or B, indicating that there are three possible scenarios: only A, only B, and both A and B. The phrase " / and" in the text refers to A and B, indicating that there are two possible scenarios: only A and both A and B.

[0049] In one embodiment provided in this disclosure, the neutron extraction syringe 3 includes: a neutron conduit 31, the lumen of which is formed as a high vacuum and the inner surface is provided with a neutron super-mirror coating for transporting thermal neutrons by total reflection; and a guide needle 32, which is detachably sleeved on the outside of the end of the neutron conduit 31 for establishing a channel for the end of the neutron conduit to enter the patient's body, so as to guide the end of the neutron conduit to the treatment site through the channel.

[0050] See Figures 1-5 , Figure 9 and Figure 10 As shown, the high vacuum environment inside the neutron conduit 31 can eliminate the scattering effect of gas molecules on thermal neutrons, enabling thermal neutrons to undergo efficient and low-loss total internal reflection transmission on the inner wall of the neutron super mirror coating. This not only improves the neutron transport efficiency from the moderator to the treatment target and ensures that the thermal neutron flux reaching the tumor site meets the treatment requirements, but also effectively reduces the requirements for neutron source intensity and lowers equipment costs.

[0051] The application of a neutron super-mirror coating, by extending the critical angle of total internal reflection, enables the capture and guidance of thermal neutrons at more angles, further enhancing the focusing and transmission capabilities of the neutron conduit. Its superior admittance properties ensure a high degree of energy uniformity for the thermal neutrons, resulting in neutrons reaching the treatment site with extremely high boron-10 (… 10 B) Capture the reaction cross section to maximize the production efficiency of alpha particles and lithium nuclei, thereby precisely and efficiently killing tumor cells.

[0052] The main function of the guide needle 32 is to be fitted onto the outer side of the tip of the neutron catheter 31, thereby assisting the tip of the neutron catheter 31 in puncturing into the patient's body and accurately reaching the tumor treatment site; providing a channel for the neutron catheter 31 to enter the body. Based on the puncture function of the guide needle 32, the tip of the neutron catheter 31 can be precisely delivered to deep tumor tissue in a minimally invasive manner. The guide needle 32 is detachable and removable, allowing for the replacement of appropriate needle sizes for different treatment depths and sites, improving treatment flexibility and adaptability, effectively avoiding medical risks that may arise from catheter breakage, and facilitating replacement and sterilization after use, thus balancing treatment safety and ease of operation.

[0053] During operation, the neutron conduit is responsible for the efficient transport of neutrons. (See also...) Figure 7 As shown, the neutron conduit is coated with a special super-mirror coating (such as a Ni / Ti multilayer film). Utilizing the principle of total internal reflection, it efficiently transmits neutrons from the source to the outlet, much like optical fibers transmit light. (See also...) Figure 5 , Figure 9 and Figure 10 As shown, the guide needle 32, which wraps around the end of the neutron catheter 31, serves only as a "protective sheath" and "channel" for the catheter's end. In interventional BNCT devices, the guide needle 32 punctures the tissue to establish a physical channel to the tumor. The fragile neutron catheter 31 (usually made of glass) enters the body through the hollow channel inside the guide needle 32, preventing breakage during the puncture process.

[0054] Specifically, see Figure 7As shown, the neutron super mirror coating is formed by alternating deposition of high-scattering-length-density materials and low-scattering-length-density materials. This multi-layered alternating structure can form a crystalline structure capable of generating strong Bragg reflection of thermal neutron waves. Each pair of high- and low-material layers forms a reflective interface, and the difference in their coherent scattering length densities determines the reflectivity of the interface. The thickness and number of periods of each layer allow for constructive interference between the acoustic waves reflected from thermal neutrons of different wavelengths (corresponding to different kinetic energies) at the interfaces, thereby expanding the critical angle for total internal reflection of neutron waves on the inner wall of the conduit. This enables more large-angle incident thermal neutrons to be efficiently captured and confined within the conduit for transmission, overcoming the inherent limitation of a very small critical angle for total internal reflection with a single material, and improving the focusing ability and transmission efficiency of the neutron conduit 31. It should be noted that the side closest to the neutron conduit cavity is made of a high-scattering-length-density material.

[0055] In practical applications, the thickness of the multilayer film can be optimized to produce the strongest reflection effect for thermal neutrons in a specific energy range (especially the thermal neutron energy region), preferentially transporting the highest boron-10 ( 10 B) The thermal neutrons are captured at the reaction cross section, while neutrons with excessively high or low energy are lost through transmission because they cannot meet the Bragg condition. Ultimately, the thermal neutron beam efficiently delivered to the treatment site not only has high flux but also single, pure energy, maximizing the induction of [the desired reaction]. 10 B(n, α) 7 Li nuclear reaction precisely kills tumor cells and effectively reduces additional radiation damage to normal tissues caused by the transmission of non-ideal energy neutrons.

[0056] In a preferred embodiment provided in this disclosure, the tube body (substrate) of the neutron conduit is made of one of the following materials: glass, nickel-titanium alloy, and silicone. A neutron super mirror coating is formed on the inner surface of the tube body. The neutron super mirror coating uses alternating deposition of materials with high coherence scattering length and high nuclear density and materials with low coherence scattering length and low nuclear density. Because neutrons exhibit wave-particle duality, when neutrons pass through two media with different refractive indices, the neutron wave exhibits properties similar to light waves. Part of the incident neutrons is reflected by the mirror, and the other part is refracted through the mirror. Since the refractive index n < 1 for most materials, according to Snell's law, when neutrons are incident from a vacuum or air onto the surface of many materials, the angle between the incident direction and the mirror (i.e., the incident angle θ < θ0) is greater than or equal to the refractive index n. c (The critical angle for total internal reflection of neutrons by a material) will result in total internal reflection; the critical angle for total internal reflection. With neutron wavelength Material coherent scattering length b coh The atomic nucleus density ρ of the material is related and can be calculated using the following formula:

[0057] (1)

[0058] In formula (1), where b coh The coherent scattering length of the material can be obtained from the NIST nuclear database, where ρ is the atomic nucleus density of the material. The wavelength of a neutron (in nm) can be determined using the following de Broglie relation:

[0059] (2)

[0060] In formula (2), h is Planck's constant (6.626 × 10⁻⁶). -34 Js), m is the rest mass of the neutron (1.675 × 10⁻⁶). - 27 Kg), E is the kinetic energy of the neutron (unit: eV). Because the neutron wavelength is relatively short, the critical reflection angle θ... c At around 1°, this can be addressed by alternating deposition of high-scattering-length-density and low-scattering-length-density materials, using Bragg reflection to extend the critical angle θ of total internal reflection of neutrons on the inner surface of the conduit. c To obtain a greater thermal neutron flux.

[0061] The guide needle 32 is a replaceable needle with one open end and the other closed end. The wall thickness of the closed end is ≤0.1mm, allowing thermal neutrons to penetrate efficiently. The end of the neutron conduit 31 can enter the hollow channel inside the guide needle 32 from the open end 321 of the guide needle 32. The end of the neutron conduit 31 is flush with the end of the guide needle 32. The guide needle 32 creates a microchannel in the human body, assisting the end of the neutron conduit 31 to enter the designated position in the human body and preventing the neutron conduit 31 from breaking in the human body.

[0062] Because thermal neutrons have extremely low energy (approximately 0.025 eV), their mean free path in air is very short, limiting their movement within a limited range after being output from the catheter. In this context, the neutron catheter, guided by a needle, can accurately reach the tumor treatment site, helping thermal neutrons to target the recipient area precisely.

[0063] This invention uses a neutron catheter to directly inject thermal neutrons into the patient's body. 10The nuclear reaction of B nuclides reduces the structural complexity of the neutron moderator. Compared to traditional boron neutron capture therapy devices that use hyperthermic neutrons, the neutron moderator of this invention only needs to consider reducing the energy of all neutrons as much as possible, thus eliminating the need for structures such as thermal neutron absorption layers and gamma shielding layers, thereby improving neutron utilization. In addition, the delivery method of directly injecting thermal neutrons into the human body avoids the radiation damage caused to the human body by secondary moderation of hyperthermic neutrons in the human body in traditional technologies. Moreover, the average energy of the injected thermal neutrons can be much lower than the average energy of thermal neutrons generated by secondary moderation in the human body, which means that the directly injected thermal neutrons have a higher nuclear reaction cross section. Finally, compared with traditional technologies, the delivery method of directly injecting thermal neutrons in this invention can easily deliver thermal neutrons to very deep sites, and the treatment depth is easily adjustable. At the same time, it causes almost no radiation damage to normal cells along the delivery path, making it safer and more efficient.

[0064] Furthermore, the high scattering length density material is one of nickel, iron, and carbon; the low scattering length density material is one of titanium, vanadium, and aluminum.

[0065] Specifically, materials such as nickel and iron have high neutron coherence scattering lengths and nuclear densities, providing strong neutron scattering potentials; while titanium, vanadium, and aluminum have relatively low corresponding values, creating a significant difference in scattering potential. This strong contrast maximizes the neutron optical potential difference at the interface of each pair of material layers, thus creating an extremely clear and efficient reflective interface for Bragg reflection. This improves the reflectivity of each reflective interface, enabling multilayer film neutron supermirrors made of these materials to achieve near total internal reflection over a wider grazing angle range. This enhances the focusing and guiding efficiency of neutron conduits, ensuring that higher fluxes of thermal neutrons are delivered to the treatment site without damage.

[0066] Furthermore, the listed material combinations (such as Ni / Ti, Ni / V, Fe / Al, etc.) exhibit excellent physical stability and chemical inertness in a vacuum environment, are not easily volatilized, and are not easily interdiffused to form alloys, thus ensuring the long-term stability and service life of the multilayer film structure.

[0067] In this disclosure, the neutron catheter 31 is configured as a rectangular tube, a circular tube, or a multi-capillary tube. In this way, the most suitable type of neutron catheter 31 can be selected according to the specific needs of different clinical scenarios (such as the depth, size, and shape of the tumor and the sensitivity of the surrounding normal tissue), thereby optimizing and customizing the treatment performance and enhancing the applicability and effectiveness of this interventional boron neutron capture therapy device.

[0068] Specifically, the rectangular neutron conduit 31 (i.e. the rectangular tube mentioned above) has a flat inner wall that allows for precise constraint and control of the neutron beam shape, which is beneficial for forming a regular irradiation field and easy for tight array-style integration, thereby achieving higher neutron flux transmission efficiency in a specific direction.

[0069] The inner wall of the circular neutron conduit 31 (i.e. the circular tube mentioned above) can provide a uniform constraint force for total reflection of neutrons, avoiding performance differences in any direction and making the neutron beam transmission more stable and balanced; at the same time, the circular structure has a uniform stress distribution and stable performance when subjected to external pressure and high vacuum negative pressure.

[0070] The multi-capillary structure is composed of a large number of micron-scale capillaries. Through the independent guidance of each capillary, the incident wide beam of thermal neutrons is efficiently focused into a high-intensity, small-focal-spot microbeam. This not only increases the local neutron flux density at the treatment target, thereby shortening the treatment time, but also achieves extremely high spatial resolution, making it possible to accurately target tiny tumor lesions.

[0071] In this disclosure, the cross-sectional area of ​​the inlet end of the neutron conduit 31 is larger than that of the outlet end. The tapered neutron supermirror channel formed by the inner wall can efficiently guide and compress the thermal neutron flow collected from a larger area of ​​the neutron moderator 2 to an outlet end with a significantly reduced cross-sectional area through a continuous total internal reflection process. This allows the thermal neutron flow to be continuously focused during transmission, increasing the thermal neutron flux density per unit area at the outlet and forming a neutron beam with a higher intensity than that at the inlet. In this way, the larger diameter end can increase the area for neutrons to enter the conduit, allowing more thermal neutrons to enter. The smaller diameter end allows thermal neutrons to enter the human body more effectively, reducing damage. When thermal neutrons exit from the smaller diameter end of the neutron conduit 31, they will exit in various directions.

[0072] The high-intensity thermal neutron beam focused at a tiny outlet maximizes the nuclear reaction rate between the neutrons and boron-10 within tumor cells, delivering a sufficient therapeutic dose in a very short time. This effectively shortens the time required for a single treatment, increasing the treatment throughput and operational efficiency of the device. At the same time, it allows the high-intensity neutrons with a relatively small irradiation area to be precisely confined to a tiny area within the tumor tissue, thereby minimizing unnecessary radiation exposure to surrounding normal tissues and critical organs.

[0073] In one embodiment provided in this disclosure, the neutron generator 1 includes: an accelerator drift tube 11, the interior of which is a vacuum channel for guiding a high-energy particle beam; a target chamber 13 connected to the accelerator drift tube 11; a neutron target 12 disposed in the target chamber 13 for being bombarded by the high-energy particle beam to generate neutrons; and a cooling device for cooling the target chamber 13.

[0074] The internal vacuum channel of the accelerator drift tube 11 provides a low-loss transmission path for the high-energy particle beam, ensuring the energy and focusing performance of the particle beam, enabling it to efficiently and accurately bombard the neutron target 12 within the target chamber 13. As the site of nuclear reactions, the specific target material selection (such as lithium-7 or beryllium-9) of the neutron target 12 ensures the stable generation of neutrons with the expected energy spectrum and flux under high-energy particle bombardment, providing a stable neutron source for subsequent treatment.

[0075] The cooling device integrated into the target chamber 13 can continuously remove the large amount of heat generated by the nuclear reaction, which can effectively prevent the neutron target 12 from melting, sputtering or degrading due to instantaneous high temperature, ensuring the long-term stability of neutron yield and the service life of the target material. By maintaining the temperature of the target chamber 13 and the entire generator structure within a safe range, equipment failure or inaccuracy caused by thermal stress or thermal deformation can be avoided, enabling the equipment to operate stably and reliably.

[0076] In this disclosure, the accelerator drift tube 11 includes a large sealing ring 111, a gripping plate 112, a copper tube 113, and a small sealing ring 114. The gripping plate 112 connects the accelerator drift tube 11 to the high-energy particle accelerator. The large sealing ring 111 is installed in a pre-drilled groove on the gripping plate 112 to maintain a sealed connection between the gripping plate 112 and the accelerator. The copper tube 113 is connected to the target chamber 13 via screws. A vacuum is drawn inside the copper tube to guide high-energy particles emitted from the accelerator to bombard the neutron target 12, generating fast neutrons. The small sealing ring 114 is installed between the copper tube 113 and the target chamber 13 to maintain a sealed connection between the copper tube 113 and the target chamber 13. The neutron target 12 is installed in a groove inside the target chamber 13. The cooling water chamber of the target chamber 13 is connected to a cooling water pipe 14, using water cooling to cool the neutron target.

[0077] Specifically, in this embodiment, the gripper disk 112 is a stainless steel disk with an outer diameter of 180 mm, and the copper tube 113 is a copper tube with an inner diameter of 25 mm and an outer diameter of 40 mm; the high-energy particles emitted by the accelerator are protons (2.5 MeV), and the neutron target 12 is... 7 Li target; target chamber 13 is a cylindrical structure with an outer diameter of 40mm and a height of 32mm. A circular groove is provided on one side and a cooling water chamber is provided on the other side. The cooling water chamber is connected to the cooling water pipe 14. The cooling water pipe 14 is a copper pipe with an inner diameter of 6mm and an outer diameter of 7mm, which is connected to an external water source and a drain.

[0078] Specifically, the neutron target material is either lithium-7 or beryllium-9. Using a lithium-7 target, the reaction between the target and protons... 7 Li(p,n) 7The Be nuclear reaction can produce neutrons with a pure energy spectrum and moderate energy. When the proton energy is slightly above the reaction threshold (about 1.88 MeV), the reaction can produce near-thermal neutrons with kinetic energy mainly in the kiloelectron volt (keV) range. This simplifies the structure and size required for the subsequent moderation process. At the same time, it can effectively reduce the production of harmful gamma rays that accompany fast neutron moderation, thus improving the safety of the treatment.

[0079] By using a beryllium-9 target, the interaction between the target and the deuterium nucleus... 9 Be(d,n) 10 The B-nuclear reaction is renowned for its extremely high neutron yield. This reaction can provide a neutron beam with an intensity far exceeding that of many other nuclear reactions, and its direct benefit is providing a powerful initial neutron flux for treatment. Even after slowing down and various efficiency losses during catheter transport, the thermal neutron flux that ultimately reaches the deep tumor site still meets the dose rate requirements for clinical treatment, thereby effectively ensuring treatment efficiency and shortening the time per treatment session.

[0080] In one embodiment provided in this disclosure, the neutron moderator 2 includes: a first moderator 21, which is wrapped around the target chamber 13 of the neutron generator 1 and is used to moderate neutrons; a first reflector 22, which is wrapped around the first moderator 21 and is used to reflect escaping neutrons and shield gamma rays; a second moderator 23, which is connected to the first reflector 22 and has a neutron conduit 31 for a neutron export syringe 3 inside, for moderating neutrons escaping from the neutron conduit 31; and a second reflector 24, which is wrapped around the second moderator 23 and is used to reflect escaping neutrons and shield gamma rays.

[0081] The first moderator 21, which is closely attached to the target chamber 13, can rapidly slow down the high-energy fast neutrons generated by the neutron generator 1 to the thermal neutron energy region. The first reflector 22, which surrounds it, can effectively reflect neutrons attempting to escape from the first moderator 21 back, causing them to re-enter the moderation process, reducing neutron loss and improving the utilization rate of neutron resources. Based on the shielding capability of the first moderator 21 against gamma rays, it can effectively absorb most of the transient gamma radiation generated during the moderation process, forming a safety barrier.

[0082] The extended second moderator 23 surrounds the neutron conduit 31, enabling secondary moderation of neutrons that have not been fully slowed down and escape from the conduit wall. This allows these potentially lost neutrons to be reused, further increasing the thermal neutron flux ultimately entering the conduit. Similar to the first reflector 22, the enclosed second reflector 24 also reflects escaping neutrons and shields residual gamma rays. Together with the first reflector 22, they form a closed shielding system, ensuring the safety of the external operating environment, minimizing radiation dose to meet radiation protection standards, and protecting the safety of medical personnel.

[0083] In one embodiment provided in this disclosure, the first moderator 21 and the second moderator 23 are made of one or more of aluminum fluoride, titanium fluoride, Teflon, polyethylene, and magnesium fluoride. The hydrogen (H) or fluorine (F) elements in these materials have small mass numbers and large scattering cross sections, enabling them to rapidly dissipate the kinetic energy of high-energy neutrons through multiple efficient inelastic collisions. This results in a shorter moderation length, reducing the required structural size of the moderator, improving the overall compactness of the device, and ensuring high-energy neutron moderation efficiency.

[0084] Compared to other moderation materials, the elements in this selected material combination (such as fluorine and carbon) have a low thermal neutron capture cross section and an extremely high (n, γ) reaction threshold. They have a very low probability of absorbing thermal neutrons during the moderation process and are extremely difficult to excite by high-energy neutrons to produce transient, high-energy secondary γ-rays. This not only maximizes the retention of thermal neutrons, enabling them to be efficiently collected by the neutron conduit 31 for therapeutic use and improving neutron utilization, but also reduces the instantaneous γ-radiation intensity associated with the moderation process, effectively reducing the load requirements on the shielding structure, improving the inherent safety of the equipment, and reducing the overall volume and weight of the radiation protection structure.

[0085] In one embodiment provided in this disclosure, the first reflector 22 and the second reflector 24 are made of lead, tungsten, or iron. The selected metallic materials, especially lead and tungsten, have extremely high mass density and atomic numbers. Their atomic nuclei can form a strong reflective wall against neutrons escaping from the moderator, effectively reflecting the neutrons back into the moderator region through elastic scattering, allowing them to re-participate in the moderation process. This helps reduce neutron leakage and improve neutron utilization efficiency, thereby providing a fundamental guarantee for ensuring the thermal neutron flux ultimately reaches the therapeutic target.

[0086] The first reflector 22 and the second reflector 24, made of lead, tungsten and iron, form a highly efficient composite shielding layer enveloping the moderator. This layer can attenuate or even completely absorb the harmful gamma radiation generated during the moderation process, reducing the radiation dose rate on the equipment surface to below a safe level and providing radiation protection for operators and patients.

[0087] The above specific embodiments further illustrate the purpose, technical solution, and beneficial effects of the present invention. It should be understood that the above are merely specific embodiments of the present invention and are not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. An interventional boron neutron capture therapy apparatus, characterized by, The device includes a neutron generator, a neutron moderator, and a neutron extraction syringe. The neutron generator is used to generate neutrons by bombarding a target with an incident high-energy particle beam. The neutron moderator is connected to the neutron generator and is used to slow down the neutrons generated by the neutron generator into thermal neutrons and to shield the gamma rays generated during the slowing process. The neutron extraction syringe is connected to the neutron moderator and is used to guide and deliver the slowed thermal neutrons to the treatment site in the patient's body. The neutron extraction syringe includes: A neutron conduit, with a high vacuum inside its lumen and a neutron super mirror coating on its inner surface, is used to transport thermal neutrons by total internal reflection. as well as, A guide needle is detachably fitted onto the outer side of the end of the neutron catheter to establish a channel for the end of the neutron catheter to enter the patient's body, so as to guide the end of the neutron catheter to the treatment site through the channel.

2. The interventional boron neutron capture therapy device according to claim 1, characterized in that, The neutron super mirror coating is formed by alternating deposition of high scattering length density materials and low scattering length density materials.

3. The interventional boron neutron capture therapy device according to claim 2, characterized in that, The high scattering length density material is one of nickel, iron, and carbon; the low scattering length density material is one of titanium, vanadium, and aluminum.

4. The interventional boron neutron capture therapy device according to claim 1, characterized in that, The neutron conduit is configured as a rectangular tube, a circular tube, or a multi-capillary tube; And / or, the cross-sectional area of ​​the inlet end of the neutron conduit is greater than the cross-sectional area of ​​the outlet end.

5. The interventional boron neutron capture therapy device according to claim 1, characterized in that, The guide needle is made of 316L medical stainless steel, acrylonitrile-butadiene-styrene, polycarbonate, or polypropylene.

6. The interventional boron neutron capture therapy device according to claim 1, characterized in that, The neutron generator includes: The accelerator drift tube has a vacuum channel inside, which is used to guide the high-energy particle beam; The target chamber is connected to the accelerator drift tube; A neutron target, disposed within the target chamber, is designed to be bombarded by a high-energy particle beam to produce neutrons; and, A cooling device is used to cool the target chamber.

7. The interventional boron neutron capture therapy device according to claim 6, characterized in that, The neutron target is made of lithium-7 or beryllium-9.

8. The interventional boron neutron capture therapy device according to claim 1, characterized in that, The neutron moderator includes: The first moderator is wrapped around the target chamber of the neutron generator and is used to moderate neutrons; The first reflector, which is wrapped around the first moderator, is used to reflect escaping neutrons and shield gamma rays; A second moderator, connected to the first reflector, has a neutron conduit inside for the neutron extraction syringe, used to moderate neutrons escaping from the neutron conduit; and, The second reflector, which is wrapped around the second moderator, is used to reflect escaping neutrons and shield gamma rays.

9. The interventional boron neutron capture therapy device according to claim 8, characterized in that, The materials of the first moderator and the second moderator are one or more of aluminum fluoride, titanium fluoride, Teflon, polyethylene and magnesium fluoride; And / or, the materials of the first reflector and the second reflector are lead, tungsten or iron.

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