On top of that, the hydrophilic linker (PEG2)between chelator and GRPR-targeting moiety ensured a rapid clearancefrom the background though the urinary system.24 Intrigued by the rapid clearance from the healthy tissueswith a rather high tumor uptake, we hypothesized that exchange ofthe DOTAGA chelator (2-(4,7,10-tris(carboxymethyl)-1,4,7,10-tetraazacyclododecan-1-yl)pentanedioicacid) with a chelator more suitable for Ga-68 labeling should resultin the development of a PET tracer able to visualize GRPR-expressinglesions with high contrast shortly after administration. This evidence concerns the gene GRPR and neoplasm.