Angiogenesis Imaging Using ⁶⁸Ga-RGD PET/CT: Therapeutic Implications

Angiogenesis imaging is important for diagnostic and therapeutic treatment of various malignant and nonmalignant diseases. The Arg-Gly-Asp (RGD) sequence has been known to bind with the α_vβ₃ integrin that is expressed on the surface of angiogenic blood vessels or tumor cells. Thus, various radiolabeled derivatives of RGD peptides have been developed for angiogenesis imaging. Among the various radionuclides, ⁶⁸Ga was the most widely studied for RGD peptide imaging because of its excellent nuclear physical properties, easy-to-label chemical properties, and cost-effectiveness owing to the availability of a ⁶⁸Ge-⁶⁸Ga generator. Thus, various ⁶⁸Ga-labeled RGD derivatives have been developed and applied for preclinical and clinical studies. Clinical trials were performed for both malignant and nonmalignant diseases. Breast cancer, glioma, and lung cancer were malignant, and myocardial infarction, atherosclerosis, and moyamoya disease were nonmalignant among the investigated diseases. Further, these ⁶⁸Ga-labeled RGD derivatives could be applied to assess the effects of antiangiogenic treatment or theragnosis or both, of cancers. In conclusion, the angiogenesis imaging technology using ⁶⁸Ga-labeled RGD derivatives might be useful for the development of new therapeutic assessments, and for diagnostic and theragnostic applications.