Simplified and reproducible radiochemical separations for the production of high specific activity ~(61)Cu, ~(64)Cu, ~(86)Y and ~(55)Co

摘要

Four positron-emitting radiometals ~(61)Cu, ~(64)Cu, ~(86)Y and ~(55)Co are increasingly being employed as labels for positron emission tomography (PET) imaging due to their favorable half-lives that match the pharmacokinetics of targeting moeities such as peptides, antibodies and antibody fragments and due to their use in internal dosimetry and treatment planning of targeted radionuclide therapy when they are substituted by their therapeutic analogues ~(67)Cu, ~(90)Y and ~(58m)Co. The main disadvantage of the production methods reported in the literature for these radionuclides is that the final separated radioactive product is diluted in a large volume (> 5 mL), which obligates a lengthy evaporation step in a large vessel that is difficult to automate in-line after the chromatographic steps and that results in a highly variable amount of radioactivity lost in the vessel's surface. In this work we present simplified radiochemical separation methods for the production of ~(61)Cu, ~(64)Cu, ~(86)Y and ~(55)Co that result in: 1) a final eluate volume ≤ 600 μL; 2) reproducible separation yields of 84± 4%, 82±6%, 94±5% and 93±6%, respectively; and 3) effective specific activities of 64.0±45.0 GBq/μmol NOTA, 114.9±40.1 GBq/μmol NOTA, 1.4±0.5 GBq/μmol DTPA and 10.1±5.7 GBq/μmol NOTA, respectively; without compromising the recycling efficiencies of the respective isotopically-enriched target materials ~(60)Ni, ~(64)Ni, ~(86)SrCO_3 and ~(58)Ni, which accounted for 98±1%, 96±3%, 90±3% and 94±1%, respectively.