Efficient preparation of high-quality 64Cu for routine use

IntroductionCopper-64 is an attractive radionuclide for positron emission tomography and is emerging as a radiotherapeutic agent. The demand of 64Cu with low metallic impurities has increased because of its wide applications when incorporated with antibodies, peptides, and proteins. In this study, we propose a new separation method to produce high-quality 64Cu using a cation exchange column, as well as an automated separation system suitable for large-scale production.Methods64Cu was produced from an electrodeposited 64Ni target via the 64Ni(p,n)-reaction with a 24 MeV HH+ beam at 10 eμA (electrical microampere) conducted for 1–3 h. The irradiated target was transported to a hot cell and disassembled remotely. 64Cu was separated by a solvent mixture of HCl and acetone on a cation-exchange resin, AG50W-X8. The chemical purity of 64Cu final product was evaluated using ion-chromatography coupled with a UV detector and inductively coupled plasma mass spectroscopy for quality as well as metallic impurities.ResultsWe obtained 64Cu in dried form at a yield of 5.2–13 GBq at the end of separation, or 521 ± 12 MBq/eμA h as the final product within 2.5 h of processing time. The metallic impurities were a satisfactory low level in the order of ppb. Major contaminants of Co and Ni were lower than those samples obtained by a widely accepted separation using an anion-exchange resin.ConclusionUsing a cation-exchange resin and a systematic operation, we successfully reduced the contamination level of the 64Cu product. As a straightforward separation method, which shortened the entire processing time, we obtained a satisfactory amount of high-quality 64Cu available for routine use.