Coordination-Mediated Synthesis of Ga-Labeled Purification-Free Trivalent Probes for in Vivo Imaging of Saturable Systems.

A large excess of unlabeled ligands over gallium-67 (Ga) provides Ga-labeled probes with high radiochemical yields in a short reaction time. However, the unlabeled ligands hinder target accumulation of radiolabeled probes by competing for target molecules. To circumvent the problem, we investigated the way to prepare Ga-labeled multivalent probes from monovalent ligands.