Tumor targeting with Tc radiolabeled peptides: Clinical application and recent development.

Targeting overexpressed receptors on the cancer cells with radiolabeled peptides has become very important in nuclear oncology in the recent years. Peptides are small and have easy preparation and easy radiolabeling protocol with no side-effect and toxicity. These properties made them a valuable tool for tumor targeting. Based on the successful imaging of neuroendocrine tumors with In-octreotide, other receptor-targeting peptides such as bombesin (BBN), cholecystokinin/gastrin analogues, neurotensin analogues, glucagon-like peptide-1, and RGD peptides are currently under development or undergoing clinical trials. The most frequently used radionuclides for tumor imaging are Tc and In for single-photon emission computed tomography and Ga and F for positron emission tomography imaging. This review presents some of the Tc-labeled peptides, with regard to their potential for radionuclide imaging of tumors in clinical and preclinical application.