THE PURIFICATION AND THE QUALITY CONTROL OF 68Ga ELUATES FROM 68Ge/68Ga GENERATOR

Today the majority of positron emission tomography (PET) studies are performed with F-18 radiophannaceuticals requiring an on-site cyclotron or shipment from a site in close proximity to the place where the investigation is performed. Generator based radionuclides would allow easier availability and more flexibility in use. Ge-68/Ga-68 generators provide cyclotron-independent access to PET radiopharmaccuticals. Ga-68 is a short lived positron emitter (half-life 67.6 min) and is coming from his parent Ge-68, which have a half-life of 270.8 days. The 270 days half-life of the parent allows the use of the generator for a long period, potentially up to 1 year or even longer. The 67.6 minutes half-life of the Ga-68 matches the pharmacokinetics of many peptides and other small molecules owing to rapid diffusion, localization at the target and fast blood clearance. The Ga-68 solutions eluted from the generator are usually containing small amounts of other cations. Before the radiolabelling of peptides with it we have to purify the eluate. Because of the metallic impurities (Fe, Zn, breakthrough of Ge), the eluate has to be purified either on a cation exchange column, on an anion exchange column or both of them, combined. In this paper the results obtained after the purification on a cation exchange column, anion exchange column, both of them and fractioned elution will be presented. Purification using anion resin and fractioned elution are feasible leading to a high quality eluate suitable for peptide radiolabelling.