Cyclotron production and radiochemical separation of 55Co and 58mCo from 54Fe, 58Ni and 57Fe targets

This work presents the production with a cyclotron of the positron emitter Co-55 via the Fe-54(d,n) and Ni-58(p,alpha) reactions and the Auger electron emitter Co-55m via the Fe-57(d,n) reaction after high current (40 mu A p and 60 mu A d) irradiation on electroplated targets. High specific activity radionuclides (up to 55.6 GBq/mu mol Co-55 and 31.8 GBq/mu mol Co-55m) with high radionuclidic purity (99.995% Co-55 from Fe-54, 98.8% Co-55 from Ni-58, and 98.7% Co-55m from Fe-57 at end of bombardment, EoB), in high activity concentration (final separated radionuclide in < 0.6 mL) and with almost quantitative overall activity separation yield (> 92%) were obtained after processing of the irradiated targets with novel radiochemical separation methods based on HCl dissolution and the resin N,N,N',N'-tetrakis-2-ethylhexyldiglycolamide (DGA, branched). One hour long irradiations using 38-65, 110-214 and 59-78 mg of enriched Fe-54 (99;93%), Ni-58 (99.48%) and Fe-57 (95.06%), respectively, electroplated over a 1.0 cm(2) surface, yielded 58(2) +/- 66 MBq Co-55, 372 +/- 14 MBq Co-55 and 810 +/- 186 MBq Co-55m, respectively, decay corrected to EoB. The separation methods allow for the recovery of the costly enriched target materials, which were reconstituted into metallic targets after novel electroplating methods, with an overall recycling efficiency of 93 +/- 4% for iron. The produced radionuclides were used to radiolabel the angiogenesis marker antibody TRC105 conjugated to the chelator NOTA as a demonstration of their quality.