Development of a large scale production of 67Cu from 68Zn at the high energy proton accelerator: Closing the 68Zn cycle

A number of research irradiations of 68Zn was carried out at Brookhaven Linac Isotope Producer aiming to develop a practical approach to produce the radioisotope 67Cu through the high energy 68Zn(p,2p)67Cu reaction. Disks of enriched zinc were prepared by electrodeposition of 68Zn on aluminum or titanium substrate and isolated in the aluminum capsule for irradition. Irradiations were carried out with 128, 105 and 92 MeV protons for at least 24 h. After irradiation the disk was chemically processed to measure production yield and specific activity of 67Cu and to reclaim the target material. The recovered 68Zn was irradiated and processed again. The chemical procedure comprised BioRad cation exchange, Chelex-100 and anion exchange columns. Reduction of the oxidation degree of copper allowed for more efficient Cu/Co/Zn separation on the anion exchange column. No radionuclides other than copper isotopes were detected in the final product. The chemical yield of 67Cu reached 92–95% under remote handling conditions in a hot box. Production yield of 67Cu averaged 29.2 μCi/[μA−h×g 68Zn] (1.08 MBq/[μA−h×g 68Zn]) in 24 h irradiations. The best specific activity achieved was 18.6 mCi/μg (688.2 MBq/μg).

► Irradiation of recovered 68Zn resulted in high specific activity 67Cu.
► Separation procedure perfected.
► Zinc disk electroplating carried out remotely.
► Valuable target material recovered and irradiated again.