NEW GERMANIUM-68-GALLIUM-68 GENERATOR

Abstract

A Ge-Ga generator producing EDTA-free 68Ga would permit synthesis of a broad range of 68Ga radiopharmaceuticals and thus facilitate widespread application of positron tomography. A solvent-extraction generator system producing the weak complex of 68Ga with 8-hydroxyquinoline (68Ga oxine), free of EDTA, was investigated. Conditions for optimum 68Ga yield and minimum 68Ge breakthrough involved extraction with chloroform from pH 5 buffer containing Ge4+ carrier, followed by evaporation to dryness. This produces 68Ga yields of 70-80%, with 68Ge breakthrough of < 0.003%. The 68Ga oxine was readily converted to other radiopharmaceuticals such as 68Ga EDTA, 68Ga EDTMP, or 68Ga colloid and is conveniently delivered dry. The extraction system is simple and amenable to automation, and low loss rate and 280-day half-life of 68Ge provide a generator with a long useful lifetime.