Capsule for the production of medical isotopes in a pneumatic hare system

Abstract

The application relates to a capsule for producing medical isotopes by using a pneumatic rabbit system, which comprises a capsule shell, a plurality of hemispherical limiting blocks, a heat dissipation channel, an isotope target fixing structure, an annular driving fan blade and a target cabin, the hemispherical limiting blocks are arranged on the front end face of the capsule shell and used for matching and positioning with limiting grooves at the end of a transmission pipeline in the pneumatic rabbit system, the heat dissipation channel penetrates the capsule shell in the radial direction, the heat dissipation channel is in the shape of a circular truncated cone, the diameter of the front end of the heat dissipation channel is smaller than that of the rear end, the isotope target fixing structure is arranged inside or on the surface of the capsule shell, the annular driving fan blade is composed of a plurality of fan-shaped fan blades which are annularly distributed inside the heat dissipation channel, the isotope target fixing structure and the annular driving fan blade are arranged in a staggered mode, and the target cabin is fixedly connected to the isotope target fixing structure and used for sealing the isotope target. The capsule can realize posture balance and self-positioning during pneumatic transmission and has high heat dissipation performance.

Description

Technical Field

[0001] This invention relates to the fields of accelerator-based medical isotope production technology, pneumatic rabbit-running systems, and radiopharmaceutical preparation, specifically to a capsule used in a pneumatic rabbit-running system for producing medical isotopes. Background Technology

[0002] In modern medicine, cancer has become one of the major diseases seriously threatening human health. Clinical diagnosis and treatment of cancer typically employ a combination of methods, including: 1. Surgical resection, which can remove large areas of the tumor, but its efficacy against metastatic tumors is limited and the recovery period is long; 2. Chemotherapy, which has poor selectivity, strong side effects, and significant damage to normal tissues; 3. Biological therapy, which has good efficacy but is costly, applicable to a limited population, and the technology is still immature; 4. Radiotherapy, traditionally using photon external beam radiotherapy, which is technically mature, requires less investment, and is inexpensive, but causes significant damage to normal tissues and is only effective for small lesions. In recent years, new radiotherapy technologies such as proton therapy, heavy ion therapy, boron neutron capture therapy, and radiopharmaceutical therapy have developed rapidly. Radiopharmaceutical therapy, in particular, involves binding a radionuclide with a specific ligand to form a drug that is targeted and enriched in the tumor tissue. During the decay of the radionuclide, it releases alpha or beta rays, using radiation energy to precisely kill the lesion. Its radiation range is limited, but it can induce DNA damage and apoptosis in tumor cells at the microscopic level, reducing the impact on surrounding normal tissues. It is characterized by high efficiency, precision and minimal damage.

[0003] Medical isotopes are key materials for radiopharmaceutical therapy, primarily prepared via nuclear reactors or particle accelerators. Accelerator-based methods, due to their advantages such as high specific activity, high purity, and short half-life, are increasingly becoming an important direction for medical isotope preparation. Photonuclear reactions are a typical accelerator-based isotope preparation method. Through the interaction of a high-energy electron beam with a conversion target to generate bremsstrahlung photons, the photons undergo photonuclear reactions with the isotope target, enabling the efficient preparation of various key medical isotopes, such as... 225 Ac、 99 Mo / 99m Tc, 64 Cu、 67 Cu, etc. Our team has achieved innovative results in the field of photonuclear reaction preparation of medical isotopes, and has successfully applied for two national invention patents: Patent CN120299771B proposes a metal substrate, 226 Ra isotope sample, nickel plating layer and protective shell 225 Ra isotope target structure can significantly enhance medical isotope performance. 225 Ac output. Patent CN119997338B proposes a closed-loop structure that can achieve... 225 Ac、 212Online irradiation and separation of Pb, along with monitoring of yield using a photon detection system, effective handling of the radioactive radon gas produced in the reaction, and efficient heat exchange, significantly improved [the following technology / method]: 225 Ac production efficiency.

[0004] In the above photonuclear reaction preparation 225 Ac、 212 In the production of medical isotopes such as Pb, the isotope targets need to be irradiated with high-energy particle beams within a high-protection target station. Besides optimizing the target structure and reaction parameters, the transport and irradiation methods of the isotope targets are also key factors affecting production efficiency. Due to the complex environment and high radiation dose involved in the preparation of medical isotopes, the production system must have remote control and transportation capabilities to ensure rapid installation, transportation, and replacement of isotope targets, thereby improving yield and preparation efficiency.

[0005] Currently, the mainstream solutions include mechanical transmission devices and pneumatic target-running systems. Mechanical transmission devices have complex structures and many components, are prone to radiation damage in strong irradiation environments, and are difficult and costly to maintain. In contrast, pneumatic target-running systems have a simple structure, can be remotely controlled, and have a high transmission speed. They use airflow pressure difference to drive capsules loaded with isotope targets to be efficiently transported along pipelines between the target chamber and the hot chamber, enabling remote loading, unloading, and recovery of target materials, which significantly improves production efficiency and operational safety.

[0006] In pneumatic target transport systems, the target capsule is the core component for rapid and safe target transport, and its performance directly affects the stability and yield of isotope preparation. Transporting isotope targets using capsules under high-intensity irradiation conditions requires stability, precise positioning, effective heat dissipation, and reliable transport, presenting the following technical challenges: 1. During transport without external control, the capsule's attitude is unstable due to friction, airflow disturbances, and gravity. The isotope target may not be directly aligned with the incident source, affecting irradiation efficiency and yield. 2. When multiple capsules are used simultaneously for target firing, the fixed position of the isotope target needs flexible adjustment for incident sources emitted from different directions. A single structure cannot meet the needs of multiple firing operations, and the capsule's structural design must be balanced to ensure transport stability. 3. The high-intensity irradiation, high-temperature, and high-speed pneumatic environment places high demands on the capsule's material, requiring low density, radiation resistance, low activation, and high strength to ensure structural stability. 4. The capsule also needs a reasonable structure to promptly remove heat generated during firing, improving heat dissipation efficiency.

[0007] In the prior art, the invention patent with announcement number CN110808113B proposes a capsule for a pneumatic rabbit-running system, which is equipped with multiple layers of energy-reducing foil and an independent cooling system to improve the target cooling effect. However, it requires mechanical actuation to lock the target position, which is complex in structure and has high maintenance costs. The invention patent with announcement number CN118666006B discloses a pneumatic sample transport device based on magnetic positioning, which achieves positioning by mutual attraction of magnets. However, the magnetic material is prone to demagnetization under strong irradiation, resulting in insufficient long-term operational reliability. Summary of the Invention

[0008] To address existing technical challenges, this invention provides a capsule for producing medical isotopes using a pneumatic target-running system. The capsule is used to load and transport isotope targets within the system. This invention proposes two capsule structure implementation schemes for scenarios where the incident source is located at the end and side of the target head. These two schemes enable reliable transport of the isotope target at each stage of the firing process, meeting the firing requirements of incident sources from different directions. They ensure that the capsule, without relying on electronic control devices, can always position the isotope target directly opposite the incident source through a self-positioning structure, achieving optimal yield. Furthermore, the invention utilizes aluminum alloy materials with excellent thermal conductivity, low density, radiation resistance, and low activation characteristics, and uses compressed air cooled by a cold source as the air source. Combined with the design of internal heat dissipation channels and grooves, efficient heat dissipation is achieved, significantly improving the reliability of the capsule during firing.

[0009] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0010] A capsule for producing medical isotopes using a pneumatic rabbit-running system includes a capsule shell, multiple hemispherical limiting blocks, heat dissipation channels, an isotope target fixing structure, an annular drive fan blade, and a target chamber, wherein the capsule shell is cylindrical.

[0011] The hemispherical limiting block is set on the front end face of the capsule shell and is used to match and position with the limiting groove at the end of the transmission pipe in the pneumatic rabbit running system.

[0012] The heat dissipation channel extends radially through the capsule shell, and the heat dissipation channel is frustoconical in shape, with the diameter of the front end of the heat dissipation channel being smaller than the diameter of the rear end; the isotope target fixing structure is disposed inside or on the surface of the capsule shell, and is located at the front end of the capsule shell; the annular drive fan blade is composed of multiple fan-shaped fan blades, which are distributed in a ring inside the heat dissipation channel and are fixedly connected to the side wall of the heat dissipation channel; the isotope target fixing structure and the annular drive fan blade are staggered and do not interfere with each other;

[0013] The target chamber is fixedly connected to the isotope target fixing structure and is used to seal the isotope target.

[0014] Furthermore, the target chamber is fixed to the isotope target fixing structure by evenly distributed rivets.

[0015] Furthermore, the capsule shell is provided with several heat dissipation grooves.

[0016] Furthermore, when the capsule is used as a base target capsule in a scenario where the incident source is located at the end of the target head, the isotope target fixing structure is conical and located inside the heat dissipation channel at the front end of the capsule shell. The isotope target fixing structure is connected to the inner wall of the heat dissipation channel through multiple support columns, and the isotope target fixing structure and the central axis of the capsule shell are on the same straight line. The planar end of the isotope target fixing structure is close to the front end of the capsule shell, and the target chamber is fixedly connected to the planar end of the isotope target fixing structure.

[0017] Furthermore, the isotope target fixing structure has several heat dissipation grooves on its conical surface.

[0018] Furthermore, the annular drive fan blade is positioned in the middle of the heat dissipation channel.

[0019] Furthermore, the number of hemispherical limiting blocks is three or four, and the hemispherical limiting blocks are evenly distributed around the axis.

[0020] Furthermore, when the capsule is used as a side target capsule in a scenario where the incident source is located on the side of the target head, the isotope target fixing structure is in the shape of a cylindrical cut-off body, and there are two isotope target fixing structures. The two isotope target fixing structures are symmetrically arranged on the outer side walls on both sides of the front end of the capsule shell. One isotope target fixing structure is used to fix the target chamber, and the other isotope target fixing structure has a counterweight fixedly installed inside.

[0021] Furthermore, the annular drive fan blade is disposed at the front end of the heat dissipation channel and is located between the front end face of the capsule shell and the isotope target fixing structure.

[0022] Furthermore, the inner wall of the heat dissipation channel inside the capsule shell is provided with several heat dissipation grooves, and the heat dissipation grooves are located on the side close to the target chamber.

[0023] Furthermore, the number of hemispherical limiting blocks is three, and the three hemispherical limiting blocks are arranged in an isosceles triangle. The hemispherical limiting block located at the vertex of the isosceles triangle is on the same side as the target chamber, and the other two hemispherical limiting blocks are on the same side as the counterweight.

[0024] The capsule shell is a cylinder with a diameter of 4.0cm to 6cm and a height of 10cm to 12cm.

[0025] The top diameter of the heat dissipation channel is 2.5 cm ~ 3 cm, the bottom diameter is 4.5 cm ~ 5 cm, and the height is 11 cm ~ 12 cm.

[0026] The isotope target is a cylinder with a diameter of 1 cm and a height of 0.15 cm.

[0027] The target chamber is a cylinder with a diameter of 2cm and a height of 0.4cm, with a space inside for fixing the isotope target.

[0028] The hemispherical limiting block is a hemisphere with a diameter of 0.5cm.

[0029] The annular drive fan blade consists of four fan-shaped blades. The included angle of the pointed ends of the fan-shaped blades is 75°~90°, the thickness of the fan-shaped blades is 0.1cm~0.2cm, and the included angle between the fan-shaped blades and the horizontal plane is 15°~30°.

[0030] Furthermore, regarding bottom-target capsules:

[0031] The heat dissipation grooves are arranged in four groups, each group containing three parallel strip-shaped grooves symmetrically distributed on the conical surface of the isotope target fixing structure; among the three parallel strip-shaped grooves, the length of the middle strip-shaped groove is 0.7cm~0.8cm, the length of the two side strip-shaped grooves is 0.6cm~0.7cm, the width of the three strip-shaped grooves is 0.1cm~0.15cm, the depth of the three strip-shaped grooves is 0.05cm~0.1cm, and the spacing between adjacent strip-shaped grooves is 0.06cm~0.1cm.

[0032] There are four hemispherical limiting blocks, which are evenly distributed at intervals on the front end face of the capsule shell.

[0033] The bottom diameter of the conical isotope target fixing structure is 2.1 cm ~ 2.2 cm, and the height is 1 cm ~ 1.5 cm.

[0034] The distance between the bottom surface (i.e. the planar end) of the isotope target fixing structure and the front end of the capsule shell is 0.4 cm, and the top of the cone points to the rear end of the capsule shell.

[0035] The top of the target chamber is flush with the front end face of the capsule shell, and the bottom of the target chamber is in close contact with the isotope target fixing structure.

[0036] The distance between the annular drive fan blade and the front end face of the capsule shell is 6cm~7cm, and the distance between the annular drive fan blade and the isotope target fixing structure is 4cm~5cm.

[0037] Furthermore, regarding the side-target capsule:

[0038] The counterweight is a cylinder with a diameter of 2cm and a height of 0.4cm.

[0039] The isotope target fixation structure is a cylindrical excised body with a diameter of 2.1cm to 2.2cm and a height of 0.6cm to 0.8cm from the side surface of the capsule shell.

[0040] The heat dissipation groove contains six strip-shaped grooves. The width of each strip-shaped groove is 0.1cm to 0.15cm, the length is 3cm to 5cm, the depth is 0.025cm to 0.05cm, and the spacing between adjacent strip-shaped grooves is 0.25cm to 0.3cm.

[0041] The distance between the top surface of the target chamber and the side surface of the capsule shell is 0.2cm to 0.4cm, and the bottom surface of the target chamber is in close contact with the isotope target fixing structure; the distance between the side surface of the target chamber and the front end of the capsule shell is 1.1cm to 1.6cm.

[0042] The distance between the annular drive fan blade and the front end face of the capsule shell is 0.3~0.5cm.

[0043] The distance between the isotope target fixation structure and the front end face of the capsule shell is 1cm to 1.5cm.

[0044] The beneficial effects of this invention are as follows:

[0045] (1) The capsule as a whole possesses radiation resistance and low activation performance. Aluminum alloy is used as the material for the capsule shell and supporting structure. It has low density, stable crystal lattice, low atomic number, and small reaction cross section with high-energy particles, maintaining structural stability under high-energy radiation environment. The radiation resistance and low activation characteristics of aluminum alloy material ensure that the capsule can still operate reliably under long-term irradiation of high-energy particles such as photons, neutrons, and medium-to-high-energy electrons, reducing the generation of activation products and improving system safety. Aluminum alloy material takes into account low density, high strength, radiation resistance, low activation, and good thermal conductivity, making the capsule lightweight and structurally stable, which can meet the needs of high-speed transportation and multi-path parallel operation of pneumatic rabbit running system.

[0046] (2) The capsule has self-positioning capability. The hemispherical limiting block set on the front end face of the capsule and the limiting groove at the end of the transmission pipe achieve geometric matching. Combined with the tangential rotational torque generated by the annular drive fan blade, the capsule achieves self-positioning in the target chamber, so that the isotope target is always facing the incident source.

[0047] (3) The capsule has high-efficiency heat dissipation performance, adopting a frustum-shaped tapering heat dissipation channel structure. When the compressed air cooled by the cold source passes through the heat dissipation channel, the flow velocity increases as the channel narrows, achieving efficient heat exchange. The target chamber is closely attached to the isotope target, and the heat is rapidly conducted to the fixed structure of the isotope target and carried away by the continuously introduced compressed air cooled by the cold source, so that the isotope target can dissipate heat efficiently and maintain the temperature at a low level, achieving stable control of the temperature of the isotope target and the capsule, and avoiding local overheating. The capsule uses compressed air cooled by the cold source as the air source, which can achieve both transmission and effective heat dissipation, simplifying the device design.

[0048] (4) The capsule is balanced and stable. The capsule structure design adopted for different shooting schemes achieves capsule attitude balance. The bottom target capsule is a completely symmetrical structure, and the side target capsule is equipped with counterweights to further enhance the stability of the capsule during pneumatic transmission. Attached Figure Description

[0049] Figure 1 This is a simplified diagram illustrating the application scenario of the capsule structure described in this invention;

[0050] Figure 2 This is a front view of the bottom target capsule structure in this invention;

[0051] Figure 3 This is a top view of the bottom target capsule structure in this invention;

[0052] Figure 4 This is a bottom view of the bottom target capsule structure in this invention;

[0053] Figure 5 This is an isometric view of the bottom target capsule structure in this invention;

[0054] Figure 6 This is a radial cross-sectional view of the bottom target capsule structure in this invention;

[0055] Figure 7 This is a circumferential cross-sectional view of the bottom target capsule structure in this invention;

[0056] Figure 8 This is a front view of one side of the counterweight block in the side target capsule structure of the present invention;

[0057] Figure 9 This is a side view of the side target capsule structure in this invention;

[0058] Figure 10 This is a top view of the side target capsule structure in this invention;

[0059] Figure 11 This is a bottom view of the side target capsule structure in this invention;

[0060] Figure 12 This is an isometric view of the side target capsule structure in this invention;

[0061] Figure 13 This is a radial cross-sectional view of the side target capsule structure in this invention;

[0062] Figure 14 This is a front view of one side of the isotope target in the side target capsule structure of the present invention.

[0063] In the diagram: A - hot chamber, B - capsule recovery station, C - capsule delivery station, D - transmission pipeline, E - capsule firing control device, F - capsule control console, G - air compression equipment, H - target chamber, I - target head, J - incident source.

[0064] 1-Capsule shell, 2-Heat dissipation groove, 3-Hemispherical limiting block, 4-Target chamber, 5-Support column, 6-Annular drive fan blade, 7-Isotope target fixing structure, 8-Isotope target, 9-Heat dissipation channel, 10-Counterweight block, 11-Rivet. Detailed Implementation

[0065] To better understand the above-described objects, features, and advantages of the present invention, the invention will be further described in detail below with reference to the accompanying drawings and specific embodiments. Many specific details are set forth in the following description to provide a thorough understanding of the invention; however, the invention may be practiced in other ways different from those described herein, and therefore, the invention is not limited to the specific embodiments disclosed below.

[0066] This invention relates to a capsule for producing medical isotopes using a pneumatic rabbit-running system, comprising a capsule shell 1, at least three hemispherical limiting blocks 3, a target chamber 4, an annular drive fan blade 6, an isotope target fixing structure 7, and heat dissipation channels 9, wherein the capsule shell 1 is a hollow cylinder;

[0067] The hemispherical limiting block 3 is set on the front end face (i.e. the top end face) of the capsule shell 1 and is used to match and position with the hemispherical limiting groove at the end of the transmission pipe in the pneumatic rabbit running system. Designing the limiting block and its corresponding limiting groove as hemispherical helps to optimize the guiding characteristics of the contact surface, thereby improving the stability and smoothness of the matching and positioning process.

[0068] The heat dissipation channel 9 extends radially through the capsule shell 1. The heat dissipation channel 9 is frustoconical, and the diameter of the front end (i.e., the top end) of the heat dissipation channel 9 is smaller than the diameter of the rear end (i.e., the bottom end). The isotope target fixing structure 7 is disposed inside or on the surface of the capsule shell 1, and is located at the front end of the capsule shell 1. The annular drive fan blade 6 is composed of at least four fan-shaped fan blades, which are distributed in an annular pattern inside the heat dissipation channel 9 and are fixedly connected to the side wall of the heat dissipation channel 9. The isotope target fixing structure 7 and the annular drive fan blade 6 are staggered and do not interfere with each other.

[0069] The target chamber 4 is fixedly connected to the isotope target fixing structure 7 by evenly distributed rivets 11, which is used to seal the isotope target 8.

[0070] The capsule shell 1 has several heat dissipation grooves 2 inside or on its surface.

[0071] The capsule for producing medical isotopes using a pneumatic rabbit-running system of the present invention relates to two structural embodiments: a bottom target capsule and a side target capsule. The bottom target capsule is suitable for scenarios where the incident source is located at the end of the target head, and the side target capsule is suitable for scenarios where the incident source is located on the side of the target head.

[0072] like Figure 1 The schematic diagram of the working scene of the pneumatic rabbit-running system of the present invention shown includes the following parts: hot chamber A, capsule recovery station B, capsule sending station C, transmission pipeline D, capsule target control device E, capsule control console F, air compression equipment G, target chamber H, target head I, and incident source J.

[0073] In the pneumatic rabbit-running system, capsule recovery station B and capsule sending station C are located in hot chamber A. Transmission pipe D connects the various structural components. Capsule recovery station B and capsule sending station C are respectively connected to capsule target control device E through transmission pipe D. Capsule target control device E is connected to target chamber H through multiple transmission pipes D. Capsule control console F is located in capsule target control device E and can be used to temporarily store capsules. Air compression device G connects the four transmission pipes D between target chamber H and capsule target control device E, providing air source for capsule transmission. Target head I is located in target chamber H. Target head I has four incident sources J, three of which are located on the sides of target head I and one is located at the end of target head I. Correspondingly, three transmission pipes D connecting target chamber H are parallel to the sides of target head I, and one transmission pipe D is located directly below target head I.

[0074] Example 1:

[0075] like Figures 2-7 As shown, when the capsule is used as a base target capsule in a scenario where the incident source is located at the end of the target head, it includes the following structure: capsule shell 1, heat dissipation groove 2, hemispherical limiting block 3, target chamber 4, support column 5, annular drive fan blade 6, isotope target fixing structure 7, isotope target 8, heat dissipation channel 9, and rivet 11.

[0076] The capsule shell 1 has four hemispherical limiting blocks 3 evenly distributed on its front end face. The capsule shell 1 has radially penetrating heat dissipation channels 9 inside. The heat dissipation channels 9 are frustoconical in shape, and the diameter of the front end of the heat dissipation channels 9 is smaller than the diameter of the rear end. An annular drive fan blade 6, composed of four fan-shaped blades, is fixed to the inner wall of the heat dissipation channel 9. The arc-shaped ends of the fan-shaped blades are connected to the inner wall of the heat dissipation channel 9, and the pointed ends of the fan-shaped blades face the axis of the capsule shell 1. The included angle of the pointed ends of the fan-shaped blades is 75°, and the included angle (i.e., the inclination angle) between the fan-shaped blades and the horizontal plane (i.e., the end side section of the capsule shell 1) is 30°. The annular drive fan blade 6 is located in the middle of the capsule shell 1. The isotope target fixing structure 7 is a conical structure. The isotope target fixing structure 7 is connected to the inner wall of the heat dissipation channel 9 through four support columns 5. The support columns 5 are located at one end near the top of the capsule shell 1. One end of the support column 5 is connected to the inner wall of the heat dissipation channel 9, and the other end is connected to the conical surface of the isotope target fixing structure 7, so that the central axis of the isotope target fixing structure 7 and the capsule shell 1 are on the same straight line. The target chamber 4 is cylindrical in shape and is connected to the planar end of the conical isotope target fixing structure 7. The target chamber 4 is fixed at the center of the planar end of the isotope target fixing structure 7, which facilitates alignment with the incident source. In this embodiment, the target chamber 4 is fixed to the isotope target fixing structure 7 by rivets 11. The isotope target 8 is sealed inside the target chamber 4. Under the irradiation of the incident source, the isotope target 8 undergoes a nuclear reaction, thereby producing a radioactive isotope with medical application value. The heat dissipation grooves 2 are distributed on the conical surface of the isotope target fixing structure 7 to increase the surface area of ​​the isotope target fixing structure 7, enhance the heat dissipation performance of the isotope target fixing structure 7, and improve the heat dissipation effect of the isotope target 8 and the target chamber 4.

[0077] In this embodiment, the capsule shell 1 is a cylinder with a diameter of 5 cm and a height of 11.5 cm; the heat dissipation groove 2 is provided in four sets, each set containing three parallel strip-shaped grooves symmetrically distributed on the conical surface of the isotope target fixing structure 7. The middle strip-shaped groove has a length of 0.7 cm, the two outer strip-shaped grooves have a length of 0.6 cm, the width of each groove is 0.1 cm, the depth is 0.1 cm, and the spacing between adjacent grooves is 0.1 cm; the hemispherical limiting block 3 has a diameter of 0.5 cm. The target chamber 4 is a cylinder with a diameter of 2cm and a height of 0.4cm; the support column 5 is a cylinder with a diameter of 0.2cm; the isotope target fixing structure 7 is a cone with a bottom diameter of 2.2cm and a height of 1cm; the isotope target 8 is a cylinder with a diameter of 1cm and a height of 0.15cm; the heat dissipation channel 9 is a frustum with an upper bottom diameter of 3cm and a lower bottom diameter of 5cm; the rivet 11 has a head with a diameter of 0.4cm and a thickness of 0.05cm, and a body with a diameter of 0.3cm and a length of 0.5cm.

[0078] In this embodiment, the upper surface of the target chamber 4 is flush with the front end face of the capsule shell 1, and the lower surface of the target chamber 4 is in close contact with the isotope target fixing structure 7; the distance between the annular drive fan blade 6 and the front end face of the capsule shell 1 is 6cm; the distance between the flat end of the isotope target fixing structure 7 and the front end face of the capsule shell 1 is 0.4cm, and the conical tip of the isotope target fixing structure 7 points to the rear end of the capsule shell 1.

[0079] Example 2:

[0080] like Figures 8-14 As shown, when the capsule is used as a side target capsule in a scenario where the incident source is located on the side of the target head, it includes the following structure: capsule shell 1, heat dissipation groove 2, hemispherical limiting block 3, target chamber 4, annular drive fan blade 6, isotope target fixing structure 7, isotope target 8, heat dissipation channel 9, counterweight 10, and rivet 11.

[0081] The heat dissipation channel 9 radially penetrates the capsule shell 1. The heat dissipation channel 9 is frustoconical in shape, with the diameter of the front end smaller than that of the rear end. Two cylindrical hollow cylindrical isotope target fixing structures 7 (i.e., two cylindrical grooves on the side walls of the front end of the capsule shell 1) are symmetrically arranged on the outer walls of both sides of the front end of the capsule shell 1. One isotope target fixing structure 7 is used to fix the target chamber 4, and the other isotope target fixing structure 7 is used to fix the counterweight 10. The size of the isotope target fixing structure 7 is slightly larger than that of the target chamber 4. The target chamber 4 is fixed inside the isotope target fixing structure 7 on one side by rivets 11. The isotope target fixing structure 7 on the opposite side has a counterweight 10 of the same size as the target chamber 4, ensuring the overall weight balance of the capsule. The isotope target 8 is sealed inside the target chamber 4.

[0082] The heat dissipation groove 2 is located on the inner wall of the middle part of the heat dissipation channel 9 to enhance the heat dissipation effect. The annular drive fan blade 6, composed of four fan-shaped fan blades, is fixed on the inner wall of the heat dissipation channel 9 and close to the front end of the capsule shell 1. It is located between the front end face of the capsule shell 1 and the isotope target fixing structure 7. This arrangement can ensure that the gas flow rate at the isotope target fixing structure 7 is not affected, thus improving the heat dissipation effect. Three hemispherical limiting blocks 3 are distributed on the front end face of the capsule shell 1. The three hemispherical limiting blocks 3 are arranged in an isosceles triangle. The hemispherical limiting block 3 located at the vertex of the isosceles triangle is on the same side as the target chamber 4, i.e., the isotope target 8. The other two hemispherical limiting blocks 3 are on the same side as the counterweight block 10.

[0083] In this embodiment, the capsule shell 1 is a cylinder with a diameter of 5cm and a height of 11.5cm; the heat dissipation groove 2 includes six strip-shaped grooves, each strip-shaped groove being 0.15cm wide, 5cm long, and 0.1cm deep, with a spacing of 0.25cm between adjacent strip-shaped grooves; the hemispherical limiting block 3 is a hemisphere with a diameter of 0.5cm; the target chamber 4 is a cylinder with a diameter of 2cm and a height of 0.4cm; the included angle between the pointed ends of the fan-shaped blades of the annular drive fan blade 6 and the horizontal plane (i.e., the end side section of the capsule shell 1) is 75°. The angle is 30°; the isotope target fixing structure 7 is a cylindrical cut-off body with a diameter of 2.2cm and a distance of 0.8cm between it and the side surface of the capsule shell 1; the isotope target 8 is a cylinder with a diameter of 1cm and a height of 0.15cm; the heat dissipation channel 9 is a frustum with an upper diameter of 2.5cm and a lower diameter of 5cm; the counterweight 10 is a cylinder with a diameter of 2cm and a height of 0.4cm; the rivet 11 has a rivet head with a diameter of 0.4cm and a thickness of 0.05cm, and a rivet body with a diameter of 0.3cm and a length of 0.5cm.

[0084] In this embodiment, the distance between the target chamber 4 and the front end face of the capsule shell 1 is 1.1 cm; the distance between the annular drive fan blade 6 and the front end face of the capsule shell 1 is 0.5 cm; and the distance between the isotope target fixing structure 7 and the front end face of the capsule shell 1 is 1 cm.

[0085] In this embodiment, except for the isotope target 8, the material used is... 226 Apart from Ra, the rest of the capsule is made of AA 6061 aluminum alloy. This material has several advantages: its density is approximately 2.7 g / cm³, which makes the capsule lightweight, reducing inertia and improving motion stability during pneumatic transmission; it also possesses good mechanical properties, able to withstand airflow impact, acceleration, collision, and pressure while maintaining a certain degree of toughness; its good thermal conductivity allows it to quickly conduct the heat generated by the isotope target 8, and, together with the compressed air cooled by the cold source, maintains the temperature of the isotope target 8 and avoids local overheating; in addition, aluminum alloy is radiation-resistant, has low activation, mature processing technology, and is easy to process. Its high-purity crystal structure is stable, its atomic number is low, and its reaction cross section with high-energy particles is small, maintaining relative structural stability under high-energy radiation, thus ensuring the reliability and safety of the capsule during target firing.

[0086] In other embodiments, the capsule can also be made of aluminum alloy materials such as AA 6063 and AA7075. The target chamber 4 can also be made of materials such as nickel and chromium. The use of nickel as the material for the target chamber 4 has the following advantages: (1) high strength and good corrosion resistance, and can maintain structural stability in high temperature and high radiation environments; (2) good radiation resistance, stable crystal lattice, and not prone to radiation expansion; (3) high chemical inertness to radioactive metals, radium is relatively stable in it and does not easily react; (4) suitable for encapsulating target materials in vacuum or high temperature environments, especially for long-term irradiation. The use of chromium as the material for the target chamber 4 has the following advantages: (1) excellent high temperature resistance and radiation resistance, and can maintain strength in environments above 600℃; (2) strong oxidation and corrosion resistance, suitable for high-energy beam irradiation and vacuum environments; (3) high hardness, good shape retention of the capsule, and can avoid deformation; (4) chemically stable to radioactive metals and not prone to chemical reaction with radium.

[0087] Working principle of the invention:

[0088] (1) Capsule self-positioning: Capsule self-positioning is achieved by the geometric alignment between the protruding hemispherical limiting block 3 on the front end face of the capsule and the recessed limiting groove at the end of the transmission pipe. When the capsule reaches the end of the transmission pipe, the hemispherical limiting block 3 couples with the limiting groove and is simultaneously cooled by compressed air from the cold source, ensuring that the capsule remains in a fixed position at the end of the pipe, so that the isotope target 8 inside the capsule is always facing the incident source. Among them, the isotope target 8 in the bottom target capsule faces the front end face and is always aligned with the incident source. The overall structure of the capsule is designed to be completely symmetrical, with the four hemispherical limiting blocks 3 regularly distributed, serving only as a means of fixing the capsule; the three hemispherical limiting blocks 3 on the front end face of the side target capsule are irregularly distributed in an isosceles triangle, with two located on one side of the counterweight block 10 and one on one side of the isotope target 8, facing the direction of the incident source, ensuring that the isotope target 8 on the capsule is always facing the incident source under the self-positioning action. During the entry of the capsule into the target chamber and during firing, compressed air cooled by a cold source is continuously supplied to the transmission pipeline via a compressed air device to provide power for capsule transmission. When the compressed air cooled by the cold source passes through the annular drive fan blade 6, which is inclinedly arranged on the heat dissipation channel 9, it generates a tangential thrust, thereby applying a driving torque to the capsule and causing it to rotate. The combined action of the annular drive fan blade 6 and the hemispherical limiting block 3 enables the capsule to self-position within the target chamber, ensuring the capsule is stably fixed and that the isotope target 8 is always directly facing the incident source.

[0089] (2) High-efficiency heat dissipation of the capsule: The present invention adopts a truncated cone-shaped heat dissipation channel 9. When the compressed air cooled by the cold source passes through the gradually contracting heat dissipation channel 9, the air velocity increases continuously as the channel contracts, thereby enhancing the heat dissipation effect. The isotope target 8 is sealed inside the target chamber 4 and fits tightly against the inner wall of the target chamber 4 without gaps. During the firing process, the isotope target 8 continuously generates heat, which is conducted to the isotope target fixing structure 7 through the target chamber 4. For the bottom target capsule, the isotope target fixing structure 7 is set at the front end of the heat dissipation channel 9. For the side target capsule, the isotope target fixing structure 7 is set on the side of the capsule shell 1 and connected to the internal heat dissipation channel 9. The compressed air cooled by the cold source is continuously introduced into the heat dissipation channel 9 to carry away the heat, thereby achieving high-efficiency heat dissipation of the isotope target 8 and the inside of the capsule. The present invention also designs a heat dissipation groove 2, which is respectively set on the isotope target fixing structure 7 of the bottom target capsule and the heat dissipation channel 9 of the side target capsule. This design increases the surface area of ​​the structure and improves the heat dissipation efficiency, thereby achieving a better heat dissipation effect.

[0090] (3) Fixing of the isotope target and target chamber: To ensure the airtightness and good thermal conductivity of the isotope target 8 during the firing process, the target chamber 4 is reserved with only a space of the same size as the isotope target 8, thereby effectively preventing the leakage of harmful radioactive gases (such as radon) that may be generated during the firing process and eliminating safety hazards. After the target chamber 4 is sealed, it is assembled to the isotope target fixing structure 7 by rivets 11. This sealing and fixing method not only ensures a reliable connection between the target chamber 4 and the isotope target fixing structure 7, but also ensures the safety and stability of the firing device environment.

[0091] (4) Medical isotope preparation method based on photonuclear reaction: The present invention is based on the method for preparing isotopes through photonuclear reaction, specifically involving a high-energy electron beam striking a tungsten target to generate a large number of photons, which then react with... 226 The Ra target undergoes a nuclear reaction to produce 225 Ac. That is, the target medical isotope involved in the embodiments of the present invention is... 225 Ac, isotope target 8 is 226 Ra target, wherein the incident source is photons.

[0092] To verify the heat dissipation performance of the two capsule structures of this invention during irradiation target application, finite element simulation calculations were performed on the capsule model in this embodiment. A three-dimensional finite element capsule model was established using ANSYS Workbench software, based on three medical isotopes from the neutron source target station at the East China University of Science and Technology accelerator. 225 Ac production target schemes: rear-end target, U-shaped target, side target, and low-power target. The maximum temperature of isotope targets 8 loaded with two capsule structures under different wind velocities during irradiation was calculated and statistically analyzed under a beam current of 35 MeV and 0.2 mA. The isotope targets 8 in the capsule structures all adopted... 226 Ra target, in the bottom target capsule 226The Ra target temperature is shown in Table 1. (The text appears to be incomplete and contains several typographical errors. 226 The Ra target temperature is shown in Table 2, with the temperature unit being degrees Celsius (°C).

[0093] The three medical isotopes 225 Ac production target scheme, in the back-end target structure 226 The Ra target is positioned at the rear of the target chamber that houses three tungsten conversion targets; in the U-shaped target side target structure, 226 The Ra target is placed on the side of the target chamber containing 11 tungsten conversion targets; the low-power target is a 1cm thick tungsten conversion target.

[0094]

[0095]

[0096] According to the test results shown in Tables 1 and 2, as the wind speed increases, 226 The maximum temperature of the Ra target during irradiation is significantly reduced. Both capsule structures have the characteristic of significantly reducing the target material temperature with increasing cooling wind speed. The capsule structure proposed in this invention can meet the safe operation requirements of isotope targets under accelerator irradiation conditions and the heat dissipation requirements under medium and low wind speed conditions.

[0097] The specific steps for using the capsule described in this invention in the production of medical isotopes in a pneumatic rabbit-running system are as follows:

[0098] Step 1: After sealing the isotope target 8 in the target chamber 4 in the hot chamber A, the target chamber 4 is fixed to the isotope target fixing structure 7 by rivets 11. The capsule is placed in the capsule sending station C in the hot chamber A. The capsule is transported to the capsule control console F in the capsule firing control device E through the transmission pipe D of the pneumatic rabbit running system. One capsule can be transported at a time. The capsule firing control device E can deploy four capsules, that is, when firing, the target head I in the target chamber H can irradiate four capsules at the same time.

[0099] Step 2: After all capsules in the capsule firing control device E are deployed, the capsule firing control device E is isolated from the hot chamber A. The compressed air equipment G is started to continuously supply compressed air cooled by a cold source into the multi-path transmission pipeline D between the capsule firing control device E and the target chamber H. This process continues until the firing is completed.

[0100] Step 3: Under the action of compressed air cooled by the cold source, the capsule moves rapidly through the transmission pipe D towards the target chamber H. During the movement, the compressed air cooled by the cold source generates a tangential torque after passing through the annular drive fan blade 6, causing the capsule to rotate and move forward. When it reaches the end of the transmission pipe D, the capsule continues to rotate until the hemispherical limiting block 3 on the front end face of the capsule shell 1 couples with the limiting groove at the end of the transmission pipe D. At this point, the capsule position is fixed, and the isotope target 8 inside the capsule is facing the incident source J.

[0101] Step 4: Irradiation is performed. Compressed air cooled by a cold source is continuously introduced, and the heat generated by the isotope target 8 during irradiation is continuously dissipated through the heat dissipation channel 9. After irradiation, the supply of compressed air cooled by the cold source is stopped, and the capsule is recovered back to the capsule irradiation control device E along the transmission pipeline D under the action of gravity. After a series of radioactivity data measurements and tests to ensure safety, it is transported back to the capsule recovery station B in the hot chamber A through the transmission pipeline D between the hot chamber A and the capsule irradiation control device E.

[0102] This experiment, based on photonuclear reactions, applies the capsule structure of this invention to three medical isotopes at the East China University of Science and Technology Accelerator Neutron Source. 225 Ac production target scheme: back-end target, U-shaped target, side target and low power target. A simple model was established using Monte Carlo software FLUKA to simulate and calculate the partial nuclide yield of 1g radium target under beam current conditions of 35MeV and 0.2mA for ten days. The simulation results are shown in Table 3, and the unit is becquerel (Bq).

[0103]

[0104] According to the simulation results shown in Table 3, under the assumption of photonuclear reaction... 226 Ra(γ, n) 225 Ra→ 225 Under the condition that the Ac separation efficiency is 100%, the three target types—rear target, U-shaped target, side target, and low-power target—under preset conditions... 225 The maximum obtainable output of Ac is 5.37 × 10 8 Bq, 9.97×10 6 Bq, 3.65×10 8 Bq.

[0105] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. 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. A capsule for the production of medical isotopes in a gas dynamic rabbit system, characterized in that, The capsule shell is a cylinder, and the capsule shell comprises a capsule shell, a plurality of hemispherical limiting blocks, a heat dissipation channel, an isotope target fixing structure, an annular driving fan blade, and a target cabin. The hemispherical limiting blocks are arranged on the front end surface of the capsule shell and are matched and positioned with the limiting grooves at the end of the transmission pipeline in the pneumatic rabbit system. The heat dissipation channel penetrates the capsule shell in the radial direction, the heat dissipation channel is in the shape of a circular truncated cone, and the diameter of the front end of the heat dissipation channel is smaller than that of the rear end. The isotope target fixing structure is arranged inside or on the surface of the capsule shell and is located at the front end portion of the capsule shell.

2. The capsule for the production of medical isotopes for a pneumatic hare system according to claim 1, characterized in that, The target cabin is fixedly connected to the isotope target fixing structure and is used for sealing the isotope target.

3. Capsule for the production of medical isotopes for a pneumatic hare system according to claim 1 or 2, characterized in that The capsule shell is internally provided with a plurality of heat dissipation grooves.

4. The capsule for the production of medical isotopes for a pneumatic hare system according to claim 3, characterized in that, When the capsule is used as a bottom target capsule in a scenario where the incident source is located at the end of the target head, the isotope target fixing structure is in the shape of a circular cone, the isotope target fixing structure is located inside the heat dissipation channel at the front end of the capsule shell, the isotope target fixing structure is connected to the inner wall of the heat dissipation channel through a plurality of support columns, and the center axis of the isotope target fixing structure and the capsule shell are located on the same straight line.

5. The capsule for the production of medical isotopes for a pneumatic hare system according to claim 3, characterized in that, The isotope target fixing structure is provided with a plurality of heat dissipation grooves on the conical surface.

6. The capsule for the production of medical isotopes for a pneumatic hare system according to claim 3, characterized in that, The annular driving fan blade is arranged at the middle position of the heat dissipation channel.

7. The capsule for the production of medical isotopes for a pneumatic hare system according to claim 1 or 2, characterized in that, The number of the hemispherical limiting blocks is three or four, and the hemispherical limiting blocks are uniformly distributed and arranged around the axis.

8. The capsule for the production of medical isotopes for a pneumatic hare system according to claim 7, characterized in that, When the capsule is used as a side target capsule in a scenario where the incident source is located on the side of the target head, the isotope target fixing structure is in the shape of a cylindrical cutout, the number of the isotope target fixing structures is two, and the two isotope target fixing structures are symmetrically arranged on the outer side walls at the front end of the capsule shell.

9. The capsule for the production of medical isotopes for a pneumatic hare system according to claim 7, characterized in that, The annular driving fan blade is arranged at the front end portion of the heat dissipation channel and is located between the front end surface of the capsule shell and the isotope target fixing structure.

10. The capsule for the production of medical isotopes for a pneumatic hare system according to claim 7, characterized in that, The inner wall of the heat dissipation channel in the capsule shell is provided with a plurality of heat dissipation grooves, and the heat dissipation grooves are located on the side close to the target cabin. The number of the hemispherical limiting blocks is three, and the three hemispherical limiting blocks are arranged in the shape of an isosceles triangle, the hemispherical limiting block at the apex of the isosceles triangle is on the same side as the target cabin, and the other two hemispherical limiting blocks are on the same side as the counterweight.

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