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

Highlights: • ⁵⁵Co is produced via ⁵⁴Fe(d,n) and ⁵⁸Ni(p,α) with maximum power depositions ≥492 W. • The Auger-emitter ^58mCo is produced via ⁵⁷Fe(d,n) with 60 μA and 8.2 MeV. • The electroplating method for Fe allows the efficient recovery of target material. • > 92 % of the activity at EoB is eluted in 0.6 mL of HCl. • The effective specific activities with NOTA are ≥ 10 GBq/μmol. - Abstract: This work presents the production with a cyclotron of the positron emitter ⁵⁵Co via the ⁵⁴Fe(d,n) and ⁵⁸Ni(p,α) reactions and the Auger electron emitter ^58mCo via the ⁵⁷Fe(d,n) reaction after high current (40 μA p and 60 μA d) irradiation on electroplated targets. High specific activity radionuclides (up to 55.6 GBq/μmol ⁵⁵Co and 31.8 GBq/μmol ^58mCo) with high radionuclidic purity (99.995% ⁵⁵Co from ⁵⁴Fe, 98.8% ⁵⁵Co from ⁵⁸Ni, and 98.7% ^58mCo from ⁵⁷Fe at end of bombardment, EoB), in high activity concentration (final separated radionuclide in 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 ⁵⁴Fe (99.93%), ⁵⁸Ni (99.48%) and ⁵⁷Fe (95.06%), respectively, electroplated over a 1.0 cm² surface, yielded 58² ± 66 MBq ⁵⁵Co, 372 ± 14 MBq ⁵⁵Co and 810 ± 186 MBq ^58mCo, 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.