The Production and use of ~67Cu as Pharmacokinetic and Toxicokinetic Copper Tracer via the ~67Zn(n,p) ~67Cu reaction

摘要

~67Cu has ideal radiotracer properties for copper related pharmacokinetic and toxicokinetic research. Its high carrier free specific activity (2 x 10~(18) Bq/ mol) allows application without interfering with ongoing processes, while its gamma energies and half-life (2.6 d) permit repetitive live counting of individual subjects over a reasonable period. However, care should be taken in the production process that a (radio)chemical pure and reliable tracer is obtained, i.e. that can be applied in a similar form as the tracee. In this work, we showed that ~67Cu produced via the ~67Zn(n,p)~67Cu reaction and purified with anion exchange chromatography fulfils these requirements. The purified ~67Cu fraction had a half-life of 2.576(4) d and an effective specific activity of 10~(15) Bq/mol, due to trace amounts of stable copper in the zinc target. Contaminants were adequately removed and high ~67Cu to contaminant activity ratios (> 10~5) were obtained. Contaminants were mainly ~5Zn and ~60Co. Trace amounts of contaminants may interfere with the ~67Cu-signal, due to bioconcentration, but this was not observed for three freshwater fish species, an euryhaliene fish and an oligochaete. ~67Cu uptake rates were identical to those measured simultaneously with ~64Cu, indicating that ~~67Cu is a reliable tracer for waterborne copper.