In vivo, the rhCCK derivatives showed 3- (6.40 ± 1.48 %ID/g, [177Lu]Lu-(R)-DOTAGA-rhCCK-9) to 8-fold (15.7 ± 3.3 %ID/g, [177Lu]Lu-(R)-DOTAGA-rhCCK-16) higher activity levels in the tumour and 5- to 10-fold higher levels in the CCK-2R-positive stomach than the reference ligand, which was statistically significant in groups of four mice (p < 0.02). This evidence concerns the gene CCKBR and neoplasm.