GRPR and neoplasm: For this reason, we decided to design a series of pharmacophore-modified GRPR ligands that allow for easy and rapid 99mTc-labeling via a 6-carboxy-1,4,8,11-tetraazaundecane (N4) chelator conjugated to the N-terminus, and which show improved tumor-to-abdomen contrast, as bombesin-derived compounds tend to accumulate mainly in the pancreas, but also in the stomach (both GRPR-positive organs) and the intestine [17,22,32,33].