On the formation of non-radioactive copper during the production of Cu-64 via proton and deuteron-induced nuclear reactions on enriched Ni-64 targets

摘要

Routine production of Cu-64 commonly exploits the Ni-64(p,n) or Ni-64(d,2n) reactions. Above specific threshold energies, however, non-radioactive Cu-63 and/or Cu-65 are also co-produced. The non-radioactive (cold) Cu can significantly decrease the specific activity (SA) of Cu-64-labelled radiopharmaceuticals. Based on nuclear model calculations for the formation of non-radioactive Cu isotopes, theoretical specific activities (TSA) for Cu-64 were estimated. Reported current production methods, however, often yield SA values that are lower than the corresponding TSA predictions by more than an order of magnitude. Most of the non-radioactive Cu causing this has been found to originate from sources other than co-production, indicating that there is still significant potential for method improvement.