One for production 225 Ac's 226 Ra isotope target and its application

Abstract

The present invention relates to a device-produced medical isotope 225 Photonuclear reaction preparation in Ac production technology 225 Ac radium target design, specifically involving a method for producing 225 Ac's 226 Ra isotope target and its application. 226 The Ra isotope target comprises a nickel substrate, 226 Ra isotope sample, nickel electroplating layer and nickel protective shell; wherein, 226 The Ra isotope sample is evenly concentrated in the center of the nickel substrate, and the nickel electroplating layer covers 226 The outer surface of the Ra isotope sample, and the nickel substrate and nickel electroplating layer will 226 The Ra isotope sample is wrapped in the middle; the nickel protective shell wraps the nickel electroplating layer. 226 Ra isotope targets can be used in electron linear accelerators as a photonuclear reaction production 225 Ac raw material target, can improve 225 Production of Ac isotopes.

Description

Technical Field

[0001] The present invention relates to a device-produced medical isotope 225 Photonuclear reaction preparation in Ac production technology 225 Ac radium target design, specifically involving a method for producing 225 Ac's 226 Ra isotope targets and their applications. Background Art

[0002] Radionuclides used in targeted tumor therapy typically include beta-decay, alpha-decay, and Auger electron-decay radionuclides. The linear energy density of alpha particles is close to the optimal linear energy density for radiation therapy (100 keV / μm). Their range in soft tissue is approximately 30-80 μm, equivalent to the diameter of 5-10 tumor cells. This allows for highly effective tumor cell destruction while minimizing damage to adjacent normal tissue cells. Therefore, alpha-nuclides targeted therapy holds great promise for the treatment of microtumors, scattered tumors, and micrometastases.

[0003] Limited by the strict requirements of radiopharmaceuticals on the half-life, radioactivity purity, pharmacokinetics and stability of radionuclide carriers, the only α-radionuclide currently found to be suitable for treatment is 225 Ac, 223 Ra, 211 At 212 Pb, 149 Tb, 212 Bi, 213 Bi, 227 Th, 230 U and a few others. Among them, 225 Ac and its daughter nuclei can emit four alpha particles with energies of 5.5MeV to 8.4MeV during the decay process. As one of the emerging and most promising alpha therapeutic nuclides, it can be used in the development of emerging targeted alpha therapeutic drugs. As one of the rarest medical isotopes known, 225 The preparation, production and supply of Ac are much more difficult than those of common medical radionuclides.

[0004] at present 225 There are several main ways to produce Ac: (1) through the thorium-actinium generator, 229 Th decays naturally to produce carrier-free 225 Ac; (2) Low-energy proton reaction in radium target, using proton accelerator 226 Ra isotope target production 225 Ac, the nuclear reaction formula is 226 Ra(p, 2n)→ 225 Ac; (3) Thorium target high energy proton reaction, bombardment with protons 232 Th target production225 Ac, the nuclear reaction formula is 232 Th(p, x) 225 Ra→ 225 Ac; (4) radium target photonuclear reaction, using high-energy gamma rays generated by electron accelerator through conversion target 226 Ra isotope target production 225 Ac, the nuclear reaction formula is 226 Ra(γ, n) 225 Ra→ 225 Ac; (5) based on fast reactor preparation 225 Ac, the nuclear reaction formula is 226 Ra(μ - , nν) 225 Fr→ 225 Ac; currently disclosed in the prior art 225 The annual production of Ac basically does not exceed 2 Curies. 225 The high-cost production of Ac requires irradiating radium targets using an electron linear accelerator. However, the thermal energy density of the isotope target is extremely high under irradiation from the neutron source of the electron linear accelerator. However, the melting point of radium itself is low, at only 963K, making its softening temperature even lower. Furthermore, radium, a Group II element, is chemically very active and readily oxidizes in air to form radium oxide, which, combined with water and carbon dioxide in the air, forms radium carbonate. Furthermore, radium continuously decays, releasing the radioactive gas radon-222 (Rn-222). Its accumulation can cause environmental pollution and irreversible damage to the human body. Therefore, radium cannot be used solely as a target material for the production of medical isotopes. Designing an effective radium target structure remains a significant technical challenge. Summary of the Invention

[0005] The present invention is directed to using an electron linear accelerator to 226 Ra isotopes are used as raw materials and produced through photonuclear reactions 225 Ac medical isotope technology, 226 Ra element as a target material has defects in physical properties. A method for producing 225 Ac's 226 Ra isotope target, the 226 The Ra isotope target is a capsule-shaped target material. 226 Ra isotope targets can be used to produce electron linear accelerators with an energy of 35 MeV and a current of 2 mA. 225 Ac isotope, and 225 The annual production of Ac isotopes can reach more than 100 Ci.

[0006] One for production 225 Ac's 226 Ra isotope target, the226 The Ra isotope target comprises a nickel substrate, 226 Ra isotope sample, nickel electroplating layer and nickel protective shell; wherein, 226 The Ra isotope sample is evenly concentrated in the center of the nickel substrate, and the nickel electroplating layer covers 226 The outer surface of the Ra isotope sample, and the nickel substrate and nickel electroplating layer will 226 The Ra isotope sample is wrapped in the middle; the nickel protective shell covers the surface of the nickel electroplating layer.

[0007] Furthermore, the thickness of the nickel substrate ranges from 20 micrometers to 2 millimeters.

[0008] Furthermore, the 226 The thickness of the Ra isotope samples ranges from 10 μm to 3 mm.

[0009] Furthermore, the thickness of the nickel electroplating layer ranges from 10 micrometers to 10 millimeters.

[0010] Furthermore, the thickness of the nickel protective shell ranges from 10 micrometers to 10 millimeters.

[0011] On the other hand, the present invention provides a 226 Ra isotope targets are produced 225 Ac application, specifically, using electron beam to 226 The Ra isotope target is irradiated for 2 hours to 10 days, so that the 226 Ra isotope target output isotopes 225 Ac.

[0012] Furthermore, the energy of the electron beam is 35 MeV and the current intensity is 2 mA.

[0013] Furthermore, the 226 The number of Ra isotope targets is at least one.

[0014] Furthermore, an electron beam is used to 226 The irradiation time of the Ra isotope target is 20 hours to 10 days.

[0015] Furthermore, the 226 The number of Ra isotope targets is one, two or four; and all 226 The center of the Ra isotope target and the center of the electron beam spot are in a straight line.

[0016] Technical effects:

[0017] (1) The present invention adopts a nickel-radium-nickel-nickel capsule target structure design, which can effectively encapsulate 226 Ra isotope samples can avoid irradiation 226Ra raw materials are washed away by the surrounding cooling water, resulting in loss, which can improve the precious target material 226 Utilization rate of Ra.

[0018] (2) The capsule structure adopted by the present invention effectively protects 226 At the same time, the base and protective shell of the Ra isotope target are made of nickel, a material with high thermal conductivity. When the radium target is irradiated by the beam, 226 The Ra isotope target sample was cooled well.

[0019] (3) Using the design of the present invention 226 Ra isotope target structure can make 226 The radon produced by the decay of Ra is contained between the nickel substrate and the nickel electroplating layer and does not leak into the environment, thus protecting the environment and human body.

[0020] (4) Using the design of the present invention 226 The Ra isotope target structure can be irradiated with electron beams with energies greater than 10 MeV, which can significantly improve 225 Production of Ac isotopes. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 In the present invention 226 Schematic diagram of the working of Ra isotope target in the terminal target area of the electron beam.

[0022] Figure 2 In the present invention 226 Schematic diagram of the cross-sectional structure of the Ra isotope target.

[0023] Figure 3 Is to use one, two, four pieces of the present invention 226 After the Ra isotope target was irradiated for 20 hours in an electron linear accelerator with an energy of 35 MeV and a flux of 2 mA, 225 Activity change curve of Ac isotope with the extension of cooling days.

[0024] Figure 4 Is to use a piece of the present invention 226 After the Ra isotope target was irradiated for 20 hours and 10 days respectively under an electron linear accelerator with an energy of 35 MeV and a current of 2 mA, 225 Activity change curve of Ac isotope with the extension of cooling days.

[0025] Figure 5 Is to use a piece of the present invention 226 After 10 days of irradiation of the Ra isotope target in an electron linear accelerator with an energy of 35 MeV and a flux of 2 mA, 225 Ra and 225Activity change curve of Ac isotope with the extension of cooling days.

[0026] In the figure: 1. Electron beam; 2. Target chamber; 3. Tungsten conversion target; 4. 226 Ra isotope target; 41. nickel substrate; 42. 226 Ra isotope sample; 43. Nickel electroplating layer; 44. Nickel protective shell. DETAILED DESCRIPTION

[0027] In order to more clearly understand the above-mentioned objects, features and advantages of the present invention, the present invention is further described in detail below with reference to the accompanying drawings and specific embodiments. In the following description, many specific details are set forth to facilitate a full understanding of the present invention. However, the present invention may also be implemented in other ways different from those described herein. Therefore, the present invention is not limited to the specific embodiments disclosed below.

[0028] To improve the production of electron linear accelerator 225 Raw material target used in Ac—— 226 The physical strength of the Ra isotope target is achieved by photonuclear reaction in an electron linear accelerator with an energy of 35 MeV and a current of 2 mA. 225 The annual output of Ac exceeds 100 Ci, and the present invention provides a method for producing 225 Ac's 226 Ra isotope target.

[0029] One for production 225 Ac's 226 Ra isotope target, the 226 Ra isotope target 4 adopts a capsule-shaped target structure and can be used in electron linear accelerators as a photonuclear reaction production 225 Ac raw material target; 226 The Ra isotope target 4 includes a nickel substrate 41, 226 Ra isotope sample 42, nickel electroplating layer 43 and nickel protective shell 44; wherein, 226 The Ra isotope sample 42 is evenly concentrated in the center of the nickel substrate 41, and the nickel electroplating layer 43 covers 226 The outer surface of the Ra isotope sample 42, and the nickel substrate 41 and the nickel electroplating layer 43 will 226 The Ra isotope sample 42 is wrapped in the middle; the nickel protective shell 44 covers the surface of the nickel electroplating layer 43.

[0030] described 226 The preparation method of the Ra isotope target 4 includes: firstly, electroplating a Ra isotope target 41 on a nickel substrate 41 226 Ra electrolyte way, will 226 The Ra isotope sample 42 is electroplated on the surface of one side of the nickel substrate 41.226 The Ra isotope sample 42 is required to have a certain thickness and be distributed within a range of 1 cm in diameter with the center of the nickel substrate 41 as the center. 226 On one side of the Ra isotope sample 42, a nickel plating layer 43 is continuously electroplated. The nickel plating layer 43 has a certain thickness and the nickel plating layer 43 and the nickel substrate 41 are fully covered. 226 Finally, a prefabricated nickel protective shell 44 is covered on one side of the nickel electroplating layer 43 in a snap-fit manner to further strengthen the target raw material. 226 The Ra isotope sample 42 provides structural support and can also prevent the high-speed cooling water from eroding the target after high-flux gamma ray shooting. 226 Ra isotope sample 42 leaked.

[0031] like Figure 2 As shown, in this embodiment 226 The Ra isotope target 4 is a nickel substrate 41, 226 The target structure is a capsule-shaped structure consisting of a Ra isotope sample 42, a nickel electroplating layer 43, and a nickel protective shell 44. The nickel substrate 41 has a length, width, and height of 20 mm × 20 mm × 1 mm. 226 The Ra isotope material is electroplated to the center of the nickel substrate 41 to form a cylindrical shape with a diameter of 10 mm and a thickness of 2.316 mm. 226 Ra isotope sample 42; then 226 One side of the Ra isotope sample 42 is electroplated with a nickel plating layer 43. The length and width of the nickel plating layer 43 are 20 mm × 20 mm. The nickel plating layer 43 evenly covers 226 The thickness of the Ra isotope sample 42 is b=5mm, and the thickness of the nickel plating layer 43 in contact with the nickel substrate 41 is d=1.68mm. 226 In order to improve the structural strength and cooling effect of the Ra isotope target 4, a nickel protective shell 44 is covered on one side of the nickel electroplating layer 43. The length and width of the nickel protective shell 44 are 25mm×25mm. The thickness of the part where the nickel protective shell 44 is connected to the bottom surface of the nickel electroplating layer 43 is c=1mm, and the thickness of the part where the nickel protective shell 44 is connected to the nickel substrate 41 is a=5mm.

[0032] The present invention adopts capsule type 226 The structure of Ra isotope target 4 can be produced by electron linear accelerator target shooting. 225 In the application of Ac, nickel is used as a material with excellent thermal properties, high strength and corrosion resistance. 226 The structural support material of Ra isotope target 4 effectively supports the 226Ra isotope sample 42; In addition, through simulation calculation, the capsule 226 The Ra isotope target 4 can be accelerated by electron linear acceleration with energy of 35MeV and current of 2mA. 225 Ac's annual output has increased to more than 100 times.

[0033] The present invention is used to produce 225 Ac's 226 The working position of the Ra isotope target 4 in the target chamber 2 of the electron linear accelerator is shown in FIG. Figure 1 As shown, the target chamber 2 is sequentially placed with a tungsten conversion target 3 and the target of the present invention. 226 Ra isotope target 4; tungsten conversion target 3 is used to convert the electrons emitted by the electron accelerator into photons, generating bremsstrahlung, thereby 226 Ra isotope target 4 is irradiated to produce 225 Ac. The present invention 226 One to four Ra isotope targets 4 can be used in the target chamber 2. In this embodiment, one, two, and four Ra isotope targets are used respectively. 226 Ra isotope target 4 electron linear accelerator 225 The Ac production effect was tested; three tungsten conversion targets 3 were used in the target chamber 2, and the thickness of each tungsten conversion target 3 was 1 mm. 226 The Ra isotope target 4, the three tungsten conversion targets 3, the target chamber 2, and the beam spot center of the electron beam 1 are on a straight line. 226 When one, two and four Ra isotope targets 4 are used, each 226 The masses of the Ra isotope samples 42 are 1 g, 0.5 g, and 0.25 g, respectively. 226 The spacing between the Ra isotope targets 4 is 1.5 mm. 226 The distance between the Ra isotope sample 42 and the nearest tungsten conversion target 3 is 2 mm, and the distance between adjacent tungsten conversion targets 3 is 1.5 mm. The overall dimensions of the target chamber 2 are 60.0 mm × 60 mm × 77.5 mm. The parameters of the electron beam 1 are energy 35 MeV, current intensity 2 mA, Gaussian beam spot distribution, and spatial distribution half-width of 15 mm.

[0034] Use one, two or four pieces of the present invention respectively 226 After the Ra isotope target 4 is irradiated in the electron beam 1 drawn from the electron linear accelerator for 20 hours, 225 The activity of Ac isotopes changes with cooling days. Figure 3 When the cooling time is 15 days, one, two, or four tablets are used. 226 Ra isotope target 4 225 The total yield of Ac was 0.18Ci, 0.17Ci and 0.13Ci respectively, using one piece226 Ra isotope target 4 225 Ac has the highest yield.

[0035] Then use a 226 The Ra isotope target 4 was irradiated in the electron beam 1 from the electron linear accelerator for 20 hours and 10 days respectively. 225 The results of the change of Ac yield activity with cooling days are as follows Figure 4 When the cooling days are 15 days, 225 The yield of Ac reached the highest when irradiated for 20 hours and 10 days 225 The Ac yields are 0.18Ci and 2.12Ci respectively, so the optimal irradiation time is 10 days.

[0036] After one irradiation, 226 The isotopes produced in the Ra isotope target 4 are not only 225 Ac, also contains its parent nucleus 226 Ra, such as Figure 5 As shown, therefore 225 The calculation of the total yield of Ac should take into account 226 The yield of Ra and the influence of subsequent extraction process. The extraction is carried out by the stage extraction method known in the art. 226 The first 225 Ac was separated and extracted, and then the 225 The second extraction of Ac was carried out after 15 days. 225 The extraction of Ac, if the efficiency of each extraction is calculated to reach 100% of the theoretical value, the extraction efficiency of three consecutive extractions is 225 The total activity of Ac is close to the end of irradiation. 225 Total activity of Ra. Figure 5 It can be seen that after 10 days of irradiation 226 Ra isotope target 4 225 The activity of Ra is 3.91 Ci. If the electron accelerator with energy of 35 MeV and current of 2 mA is used for 300 days per year, 117.3 Ci of Ra can be extracted. 225 Ac isotope.

Claims

1. A kind of production 225 Ac's 226 The Ra isotope target is characterized by: described 226 The Ra isotope target comprises a nickel substrate, 226 Ra isotope sample, nickel electroplating layer and nickel protective shell; wherein, 226 The Ra isotope sample is evenly concentrated in the center of the nickel substrate, and the nickel electroplating layer covers 226 The outer surface of the Ra isotope sample, and the nickel substrate and nickel electroplating layer will 226 The Ra isotope sample is wrapped in the middle; the nickel protective shell wraps the nickel electroplating layer.

2. The method for producing 225 Ac's 226 The Ra isotope target is characterized by: The thickness of the nickel substrate ranges from 20 micrometers to 2 millimeters.

3. The method for producing the 225 Ac's 226 The Ra isotope target is characterized by: described 226 The thickness of the Ra isotope samples ranges from 10 μm to 3 mm.

4. The method for producing the 225 Ac's 226 The Ra isotope target is characterized by: The thickness of the nickel electroplating layer ranges from 10 micrometers to 10 millimeters.

5. The method for producing the 225 Ac's 226 The Ra isotope target is characterized by: The thickness of the nickel protective shell ranges from 10 micrometers to 10 millimeters.

6. The method according to any one of claims 1 to 5. 226 Ra isotope targets are produced 225 The application of Ac is characterized by: Using electron beam current 226 The Ra isotope target is irradiated for 2 hours to 10 days, so that the 226 Ra isotope target output isotopes 225 Ac.

7. according to claim 6 226 Ra isotope targets are produced 225 The application of Ac is characterized by: The energy of the electron beam is 35 MeV and the current intensity is 2 mA.

8. according to claim 6 226 Ra isotope targets are produced 225 The application of Ac is characterized by: described 226 The number of Ra isotope targets is at least one.

9. according to claim 6 226 Ra isotope targets are produced 225 The application of Ac is characterized by: Using electron beam current 226 The irradiation time of the Ra isotope target is 20 hours to 10 days.

10. The method according to claim 8 226 Ra isotope targets are produced 225 The application of Ac is characterized by: described 226 The number of Ra isotope targets is one, two or four; and all 226 The center of the Ra isotope target and the center of the electron beam spot are in a straight line.

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