GRPR and neoplasm: As shown in Fig. 7a, a significant decrease in pancreatic uptake (2 ± 1%IA/g controls vs. 0.18 ± 0.05%IA/g in block, p < 0.0001) as well as in tumor uptake (11 ± 1%IA/g controls vs. 0.8 ± 0.4%IA/g in block, p < 0.0001) was observed between the animals coinjected with excess of the GRPR-antagonist NOTA-PEG2-RM26 compared to controls, further implying a GRPR-mediated process.