Target design for preparing ac-225 by accelerator irradiation of ra-226

Abstract

The invention provides a target design for preparing Ac-225 through irradiation of Ra-226 by an accelerator, and particularly provides an application of a metal niobium film in preparation of medical isotope actinide 225, the niobium metal film is selected as a covering material to cover radioactive radium deposited on a target, and therefore radioactive gas is prevented from polluting a target chamber and the environment. In addition, the annular groove is machined in the target piece base body, so that the upper surface of the target piece is kept flat after the niobium film is added, and installation of the target piece on an accelerator is facilitated.

Description

(19) State Intellectual Property Office (12) Invention Patent Application (10) Application Publication Number (43) Application Publication Date (21) Application Number 202512056154.3 (22) Application Date 2025.12.31 (71) Applicant Tsinghua University Address 100084 Tsinghua University, Haidian District, Beijing Applicant Panmedi Technology (Shenzhen) Co., Ltd. (72) Inventors Li Junfeng, Wang Jianlong, Deng Liming (74) Patent Agency Beijing Qingyihua Intellectual Property Agency (General Partnership) 11201 Patent Attorney Pan Yongyi (51) Int.Cl. H05H 6 / 00 (2006.01) H05H 13 / 00 (2006.01) (54) Invention Title: Target Design for Accelerator Irradiation of Ra-226 to Prepare Ac-225 (57) Abstract: This invention proposes a target design for accelerator irradiation of Ra-226 to prepare Ac-225. Specifically, this invention proposes the application of a niobium film in the preparation of the medical isotope actinium-225. By selecting a niobium metal film as a covering material, the radioactive radium deposited on the target is covered, thereby avoiding radioactive gas contamination of the target chamber and the environment. In addition, by processing an annular groove on the target substrate, the upper surface of the target remains flat after the niobium film is added, which facilitates the installation of the target on the accelerator. Claims: 1 page Description: 3 pages Drawings: 1 page CN 121728650 A 2026.03.24 CN 1 21 72 86 50 A 1. Application of a niobium film in the preparation of the medical isotope actinium-225. 2. The application according to claim 1, characterized in that the niobium film is used as a target in the process of preparing the medical isotope actinium-225 from radium Ra-226 by electroplating. 3. The application according to claim 2, characterized in that the target is an accelerator irradiation target. 4. The application according to claim 2, characterized in that the thickness of the niobium film is 0.005-0.1 mm. 5. The application according to claim 2, characterized in that the niobium film is completely adhered to and covers the target substrate after being pressed and formed. 6. The application according to claim 2, characterized in that the niobium film is covered by an outer copper metal frame and then sealed with screws. 7. The application according to claim 2, characterized in that a polytetrafluoroethylene seal is added between the copper metal frame and the niobium film. 8. A target for Ra-226 irradiation by a cyclotron, characterized in that the cyclotron irradiation of Ra-226 is used to prepare the medical isotope actinium-225, and the Ra-225 material on the target is covered by a niobium film.9. The target according to claim 8, characterized in that the thickness of the niobium film is 0.005-0.1 mm; optionally, the niobium film is completely adhered to and covered on the target substrate after being pressed and formed; optionally, the niobium film is covered by an outer copper metal frame and then sealed by screws; optionally, a polytetrafluoroethylene seal is added between the copper metal frame and the niobium film. 10. A method for preparing actinium-225, characterized in that the target according to claim 8 or 9 is used. Claims 1 / 1 page 2 CN 121728650 A Target design for preparing Actinium-225 by accelerator irradiation of Ra-226 Technical Field

[0001] This invention relates to the field of preparation of medical isotope actinium-225, and discloses the design of a target in the process of preparing medical isotope actinium-225 by accelerator irradiation of Ra-226. Background Art

[0002] Targeted Alpha Therapy (TAT) is a nuclear medicine therapy based on radioactive nuclides that emit alpha particles and tumor-selective carrier molecules as carriers for specific targeted cancer cells. It is a promising cancer treatment method. Actinide-225 has become one of the best choices for nuclides in TAT due to its suitable half-life, unique decay properties, and ease of coordination.

[0003] At present, the global annual production capacity of Ac-225 is about 1.8 Ci, while it is predicted that the global annual demand for Ac-225 will reach about 600 Ci in the future. Due to insufficient production capacity and the huge gap between supply and demand, the price of Ac-225 has remained high for a long time and is known as "the rarest drug on earth", once reaching a sky-high price of US$1 million / mCi. At the same time, due to the shortage of supply, although the potential of Ac-225 in the treatment of advanced cancer has been confirmed by clinical trials, research work is still hindered by the insufficient supply of raw materials, which seriously hinders the development of medical and health care.

[0004] On June 24, 2021, the China Atomic Energy Authority, together with eight other departments including the Ministry of Science and Technology, released the "Medium- and Long-Term Development Plan for Medical Isotopes (2021-2035)". The key tasks outlined in the plan include "mastering the research and development of key technologies for the irradiation and separation preparation of novel medical isotopes such as Ge-68 and Ac-225 using accelerators," increasing technological research and development, and promoting innovative development.

[0005] The technical route for preparing Ac-225 by bombarding Ra-226 with a low-energy cyclotron accelerator produces few nuclear reaction byproducts. Besides Ac-225, it basically does not produce other actinide isotopes, which is beneficial for obtaining high-purity Ac-225 and is currently the most promising method for preparing medical Ac-225.

[0006] The biggest challenge in the technical route for preparing Ac-225 by cyclotron irradiation of Ra-226 is fixing barium radium carbonate onto the target used for accelerator irradiation to ensure that it does not detach during high-energy irradiation.

[0007] On the other hand, since Ra-226 releases radioactive radon gas during decay, necessary protective measures must be taken to prevent radioactive gas contamination of the irradiation target chamber. Summary of the Invention

[0008] This invention aims to solve at least one of the problems in the prior art. This invention avoids radioactive gas contamination of the target chamber and the environment by selecting a niobium metal film as a covering material to cover the radioactive radium deposited on the target. Furthermore, by processing an annular groove on the target substrate, the upper surface of the target remains flat after the niobium film is added, facilitating the installation of the target on the accelerator.

[0009] In one aspect of this invention, the application of a niobium metal film in the preparation of the medical isotope Actinol-225 is proposed. Selecting a niobium metal film as a covering material to cover the radioactive radium deposited on the target avoids radioactive gas contamination of the target chamber and the environment. According to embodiments of the present invention, the above application may further include at least one of the following additional technical features: According to embodiments of the present invention, the niobium metal film is used in the process of electroplating radium Ra-226 to prepare the medical isotope Actinol-225 from a target.

[0010] According to an embodiment of the present invention, the target is an accelerator irradiation target. Specification 1 / 3 page 3 CN 121728650 A

[0011] According to an embodiment of the present invention, the thickness of the niobium film is 0.005-0.1 mm.

[0012] According to an embodiment of the present invention, the niobium film is completely adhered to and covered on the target substrate after being pressed and formed.

[0013] According to an embodiment of the present invention, the niobium film is covered by an outer copper metal frame and then sealed with screws.

[0014] According to an embodiment of the present invention, a polytetrafluoroethylene seal is added between the copper metal frame and the niobium film. This can increase the sealing effect.

[0015] In another aspect of the present invention, the present invention also proposes a target for Ra-226 irradiation by a cyclotron. According to an embodiment of the present invention, the cyclotron irradiation of Ra-226 is used to prepare the medical isotope actinium-225, and the Ra-225 material on the target is covered with a niobium film. Niobium metal film is selected as the covering material to cover the radioactive radium deposited on the target, thereby avoiding radioactive gas contamination of the target chamber and the environment.

[0016] According to an embodiment of the present invention, the target may further include at least one of the following additional technical features: According to an embodiment of the present invention, the thickness of the niobium metal film is 0.005-0.1 mm.

[0017] According to an embodiment of the present invention, the niobium metal film is completely adhered to the target substrate after being pressed and formed.

[0018] According to an embodiment of the present invention, the niobium metal film is covered by an outer copper metal frame and then sealed with screws.

[0019] According to an embodiment of the present invention, a polytetrafluoroethylene seal is added between the copper metal frame and the niobium metal film. This can increase the sealing effect.

[0020] In another aspect of the invention, a method for preparing actinium-225 is also provided. According to an embodiment of the invention, the method includes using the target described above. Brief Description of the Drawings

[0021] The above and / or additional aspects and advantages of the invention will become apparent and readily understood from the description of the embodiments in conjunction with the following drawings, in which: FIG1 shows the thread position of the target body; FIG2 shows the processing diagram of the pressure frame. Detailed Description of the Embodiments

[0022] To make the above-mentioned objects, features and advantages of the invention more apparent and readily understood, specific embodiments of the invention are described in detail below. Specific details are set forth in the following description to provide a thorough understanding of the invention. However, the invention can be practiced in many other ways different from those described herein, and those skilled in the art can make similar modifications without departing from the spirit of the invention; therefore, the invention is not limited to the specific embodiments disclosed below.

[0023] Example 1 This example describes the design of a target for the preparation of medical isotope actinium-225 using electroplated radium Ra-226. The design drawings are shown in Figures 1 and 2. The main method is as follows: A niobium metal film is selected as the covering material to cover the radioactive radium deposited on the target, thereby avoiding radioactive gas contamination of the target chamber and the environment. The thickness of the niobium film is 0.01-0.1 mm.

[0024] By processing an annular groove in the target substrate, the upper surface of the target remains flat after the niobium film is added, which facilitates the installation of the target on the accelerator.

[0025] Before installation, the niobium film is pressed by a mold to ensure that the niobium film and the target are completely bonded. Instruction manual 2 / 3 pages 4 CN 121728650 A

[0026] Countersunk screws are used for fixing to ensure easy installation and disassembly, and the surface of the target is flat after installation.

[0027] Before installation, the niobium film and the recessed part of the target are bonded by applying sealant.

[0028] Through the combination of the niobium film, pressure frame, and screws designed in this invention, and through the use of sealant, the radium electroplated onto the target can form a good sealed space, thereby avoiding radioactive contamination from radon gas released by radium during irradiation. Furthermore, the design of this invention maintains the overall structure of the target consistent with the dimensions of existing targets used for irradiating other materials, making it suitable for irradiation production. Existing practices have proven that the structure designed in this invention can achieve radioactive containment.

[0029] In the description of this specification, references to the terms "one embodiment," "some embodiments," "illustrative embodiment," "example," "specific example," or "some examples," etc., indicate that the specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the invention. In this specification, illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0030] Although embodiments of the invention have been shown and described, those skilled in the art will understand that various changes, modifications, substitutions and variations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the claims and their equivalents. Description 3 / 3 Page 5 CN 121728650 A Figure 1 Figure 2 Description Figure 1 / 1 Page 6 CN 121728650 A ABSTRACT The present invention provides a target design for the production of Ac- 225 by accelerator irradiation of Ra- 226. Specifically, the present invention provides the use of a metallic niobium film in the preparation of the medical isotope Ac- 225. By selecting a niobium metal thin film as a covering material to cover the radioactive radium deposited on the target, the present invention effectively prevents radioactive gas from contaminating the target chamber and the environment. In addition, an annular groove is machined into the target substrate so that the upper surface of the target remains flat after the niobium film is applied, thereby facilitating the installation of the target on the accelerator.

Claims

1. Application of niobium metal films in the preparation of medical isotope actinium-225.

2. The application according to claim 1, characterized in that, The niobium film is used as a target in the process of preparing the medical isotope actinium-225 from radium Ra-226 by electroplating.

3. The application according to claim 2, characterized in that, The target is an accelerator-irradiated target.

4. The application according to claim 2, characterized in that, The thickness of the niobium film is 0.005-0.1 mm.

5. The application according to claim 2, characterized in that, The niobium metal film is pressed and molded to completely adhere to and cover the target substrate.

6. The application according to claim 2, characterized in that, The niobium metal membrane is covered by an outer copper metal frame and then sealed with screws.

7. The application according to claim 2, characterized in that, A polytetrafluoroethylene seal is added between the copper metal frame and the niobium metal membrane.

8. A target for cyclotron irradiation of Ra-226, characterized in that, The cyclotron irradiates Ra-226 to prepare the medical isotope actinium-225, and the Ra-225 material on the target is covered with a niobium film.

9. The target according to claim 8, characterized in that, The thickness of the niobium film is 0.005-0.1 mm; Optionally, the niobium film is pressed and molded to completely adhere to and cover the target substrate; Optionally, the niobium metal film is covered by an outer copper metal frame and then sealed with screws; Optionally, a polytetrafluoroethylene seal is added between the copper metal frame and the niobium metal membrane.

10. A method for preparing actinium-225, characterized in that, The target as described in claim 8 or 9 is used.

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