The present application discloses compositions and methods of synthesis and use of labeled targeting peptides, such as octreotide, octreotate, or other somatostatin analogs or derivatives. The targeting peptide may be labeled with a therapeutic or diagnostic isotope, such as 61Cu, 62Cu, 64Cu, 67Cu, 18F, 19F, 66Ga, 67Ga, 68Ga, 72Ga, 111In, 177Lu, 44Sc, 47Sc, 86Y, 88Y, 90Y, 45Ti or 89Zr, preferably 18F or 19F. More preferably, the targeting peptide is NOTA-octreotate, NOTA-MPAA-octreotate, pyridine-NOTA-octreotate or triazole-NOTA-octreotate. The labeled targeting peptides may be used for detection, diagnosis, imaging and/or treatment of sst2+ tumors, such as neuroendocrine tumors.
