Ga-68 labeled neurotensin NTS1R ligands: Is a separation of the labeling precursor advantageous for tumor uptake?

Ziel/Aim Recently, we described new Ga-68 labeled neurotensin NTS1R PET ligands [1]. One peptidic PET ligand with high NTS1R affinity (Ki=1.2 nM) was used to explore whether separation of the PET ligand from the precursor of comparable NTS1R affinity (Ki=5.9 nM) affects tracer uptake into the tumor.