On the other hand, the tumor/muscle ratios of tumor receptor-targeting peptides, including the αvβ3 integrin-derivative 68Ga-c(RGDyK) [45] and the CXCR4-derivative 68Ga-CPCR4-2 [46] are higher (9.30 ± 3.90 and 16.6 ± 3.80, respectively, at 60 min) than that of 67Ga-NOTA-KV6 (5.05 ± 1.51 at 120 min). Here, CXCR4 is linked to neoplasm.