Scandium-44: Benefits of a Long-Lived PET Radionuclide Available from the (44) Ti/(44) Sc Generator System

Ti-44/(44) Sc radionuclide generators are of interest for molecular imaging. The 3.97 hours half-life of Sc-44 and its high positron branching of 94.27% may stimulate the application of Sc-44-labeled PET radiopharmaceuticals. This review describes the current status of Ti-44 production, Ti-44/(44) Sc radionuclide generator development, post-processing of generator eluates towards medical application, identification of ligands adequate to Sc-III co-ordination chemistry, proof-of-principle labeling of Sc-44-DOTA-octreotides, investigation of in vitro and in vivo parameters, and initial applications for molecular imaging - both in small animals and humans.