TAC1 and neoplasm: In this respect, 68Ga-NODAGA-c(RGDyK) showed the best tumor to blood ratio of 23.1 in 90 min p.i. All three tested 68Ga-RGD peptides revealed excellent tumor to blood ratios (14.7–23.1), in contrast to 68Ga-DOTA-substance P (2.8).