Both agents, only differing in the radiometal chelator system used, were evaluated in vitro regarding their GRPR- and FRα-affinities on T47D tumor cells, both showing affinities to both receptors in the low nanomolar range (IC50(GRPR)29: 3.2 ± 1.0 nM, IC50(FRα)29: 6.3 ± 1.5 nM, IC50(GRPR)30: 4.8 ± 0.9 nM, and IC50(FRα)30: 9.1 ± 1.5 nM). Here, GRPR is linked to neoplasm.