Therefore, [68Ga]Ga-DATA-TOC was selected as the first target for comparison with [68Ga]Ga-DOTA-TOC as the clinically established reference in a series of biological in vitro and in vivo models expressing the somatostatin subtype 2 receptor (hSST2), specifically (i) competition binding assays in human SST2/3/5-positive cell membranes, (ii) biodistribution and small animal PET imaging in a preclinical mCherry-expressing mouse phaeochromocytoma (MPC-mCherry) model with high SST2 density [24, 25], and (iii) clinical studies in a patient previously diagnosed with NETs. Here, SSTR2 is linked to pheochromocytoma.