[177Lu]Lu-PKB2 and [177Lu]Lu-PKB3 demonstrated high in vivo specificity, as evidenced by the significant reduction in activity uptake in the tumor and GRPR-expressing organs (pancreas, stomach, and small intestines (Xiao et al. 2001; Monstein 2006)) after co-administration of an excess of NOTA-PEG2-RM26. Here, GRPR is linked to neoplasm.