Harvesting 67Cu from the Collection of a Secondary Beam Cocktail at the National Superconducting Cyclotron Laboratory

Isotope harvesting is a promising new method to obtain isotopes for which there is no reliable continuous supply at present. To determine the possibility of obtaining radiochemically pure radioisotopes from an aqueous beam dump at a heavy-ion fragmentation facility, preliminary experiments were performed to chemically extract a copper isotope from a large mixture of projectile fragmentation products in an aqueous medium. In this work a 93 MeV/u secondary beam cocktail was collected in an aqueous beam stop at the National Superconducting Cyclotron Laboratory (NSCL) located on the Michigan State University (MSU) campus. The beam cocktail consisted of similar to 2.9% Cu-67 in a large mixture of co-produced isotopes ranging in atomic number from similar to 19 to 34. The chemical extraction of 67Cu was achieved via a two-step process: primary extraction using a divalent metal chelation disk followed by anion-exchange chromatography. A significant fraction (74 +/- 4%) of the 67Cu collected in the aqueous beam stop was recovered with >99% radiochemical purity. To illustrate the utility of this product, the purified 67Cu material was then used to radiolabel an anti-EGFR antibody, Panitumumab, and injected into mice bearing colon cancer xenografts. The tumor uptake at 5 days postinjection was found to be 12.5 +/- 0.7% which was in very good agreement with previously reported studies with this radiolabeled antibody. The present results demonstrate that harvesting isotopes from a heavy-ion fragmentation facility could be a promising new method for obtaining high-quality isotopes that are not currently available by traditional methods.