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The α_Vβ₃ integrin plays an important role in metastasis and tumor-induced angiogenesis. Targeting with radiolabeled ligands of the α_Vβ₃ integrin may provide information about the receptor status and enable specific therapeutic planning. Previous studies from our group resulted in tracers that showed α_Vβ₃-selective tumor uptake. However, these first-generation compounds predominantly revealed hepatobiliary excretion with high radioactivity found in the liver. In this report, the synthesis and biological evaluation of the first glycosylated RGD-containing peptide (RGD-peptide) for the noninvasive imaging of α_Vβ₃ expression are described. Peptides were assembled on a solid support using fluorenylmethoxycarbonyl-coupling protocols. The precursor cyclo(-Arg-Gly-Asp-d-Tyr-Lys(SAA)-) GP1 was synthesized by coupling 3-acetamido-2,6-anhydro-4,5,7-tri-O-benzyl-3-deoxy-β-d-glycero-d-gulo-heptonic …