“…We do not have a full explanation for the strong influence of the choice of radiometal. We explained the metal iondependent differences in the case of the agonists with differences in the coordination sphere as revealed by x-ray crystal structures of the model peptides Y-DOTA-D-Phe-NH 2 , Ga-DOTA-D-Phe-NH 2 and Ga(NODASA) (21,22). X-ray structures are given in the supplemental information (supplemental materials are available online only at http:// jnm.snmjournals.org).…”