Feasibility and availability of 68Ga-labelled peptides

Ga-68 has attracted tremendous interest as a radionuclide for PET based on its suitable half-life of 68 min, high positron emission yield and ready availability from Ge-68/Ga-68 generators, making it independent of cyclotron production. Ga-68-labelled DOTA-conjugated somatostatin analogues, including DOTA-TOC, DOTA-TATE and DOTA-NOC, have driven the development of technologies to provide such radiopharmaceuticals for clinical applications mainly in the diagnosis of somatostatin receptor-expressing tumours. We summarize the issues determining the feasibility and availability of Ga-68-labelled peptides, including generator technology, Ga-68 generator eluate postprocessing methods, radiolabelling, automation and peptide developments, and also quality assurance and regulatory aspects. Ge-68/Ga-68 generators based on SnO2, TiO2 or organic matrices are today routinely supplied to nuclear medicine departments, and a variety of automated systems for postprocessing and radiolabelling have been developed. New developments include improved chelators for Ga-68 that could open new ways to utilize this technology. Challenges and limitations in the on-site preparation and use of Ga-68-labelled peptides outside the marketing authorization track are also discussed.