Production and quality control of 65ZN radioisotope for medical and agricultural applications

Purpose: Today, 65Zn radioisotope is widely used in medical, biomedical and agricultural research. Some applications of this radioisotope are: zinc metabolism and absorption research in normal and tumoral tissues (1, 2, 3,4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20 ,21, 22, 23), study and imaging of brain tumors (24, 25, 26, 27, 28, 29, 30) and agricultural research (31, 32, 33, 34, 35). The idea of production of 65Zn in the country arouse according to its wide range of applications. Important physical characteristics of 65Zn radioisotope are given in table 1 (36). Table l confirms that 65Zn can be considered as a good Euger electron emitter and it can be used for therapy purposes(23). Methods: 1 Selection of the Best Reaction. A list of various nuclear reactions which may be used for the production of 65Zn radioisotope, are given in table 2 (37, 38). Among the reactions listed in table 2, those which use deuteron or 3He beams were discarded since high energy and high intensity beams of deuteron and 3He are not available in the country at present. For 66Zn(p, d)65Zn and 64Zn(n, γ)65Zn reactions, chemical separation processes are assumed to be difficult, expensive and time-taking due to the equal chemical properties of the product and the target material, so the final product would have a low specific activity. Thus the only remained choice was 65Cu(p, n)65Zn reaction. Natural copper as comprised of two stable isotopes: 65Cu (31%) and 63Cu (69%), so the possibility of replacing natural copper with 65Cu isotope as the target material was also investigated in order to reduce the total costs. 2 Cross Section Calculations for Proton Reactions with Copper. Characterization of excitation function is an important step in the determination of the beam optimal energy range. Excitation function can be given by computer codes such as ALICE code (39) or experimental methods. In the present research performed in the cyclotron department of Atomic Energy Organization of Iran (IBA, Cyclon-30), cross sections were calculated for copper (65Cu, 63Cu) reactions with 3-30 MeV protons. Results of cross section calculations for 65Cu and 63Cu are given in figures 1 and 2 respectively. (authors)