Preparing a ⁶⁸Ga-labeled Arginine Glycine Aspartate (RGD)-peptide for Angiogenesis

The α_vβ₃ integrin is a heterodimeric adhesion molecule involved in tumor cell migration and angiogenesis. The integrin is overexpressed in angiogenic tumor endothelial cells, where it typically has a low concentration. This specific expression of α_vβ₃ makes it a valid biomarker for antiangiogenic and imaging drugs. As a functional imaging modality, positron emission tomography (PET) provides information about biochemical and physiological changes in vivo, due to its unique high sensitivity at the nanomolar scale. Hence, radiometal-based PET radiopharmaceuticals have received great attention for the non-invasive quantification of tumor angiogenesis. This paper provides a systemic protocol to prepare a new radiometal-labeled peptide for the evaluation of angiogenesis. This protocol contains information about radiochemical reliability, lipophilicity, cell uptake, serum stability, and pharmacokinetic properties. The ⁶⁸Ga-RGD-peptide is one of the representative PET ligands toward α_vβ₃ integrin. Here, we introduce a protocol to prepare a ⁶⁸Ga-RGD-peptide and the evaluation of its biological efficacy.