Labeling of NGR Peptide With ¹⁸⁸Re and Its Biodistribution and SPECT Imaging in Tumor-bearing Nude Mice

To evaluate its radiochemical characteristics, biodistribution and imaging for nude mice bearing HepG2, ¹⁸⁸Re-NGR was prepared directly with 2-mercapto-ethanol as reductant and sodium gluconate as middle ligand. The labeling yield of ¹⁸⁸Re-NGR was more than 85%, and the radiochemical purity (RCP) was more than 90%. In vivo, ¹⁸⁸Re-NGR can specifically bind with tumor. The tumor uptake was (2.84±0.51)%ID/g at 1 h after injection， the uptake was(4.62±0.71)%ID/g at 12 h and remains （2.01±0.38）%ID/g for 24 h, the contrl group was (1.43±0.61)%ID/g. The ratio of tumor to muscle was 4.76 at 12 h. The xenografted tumor became visible at 1 h and was the most clearly at 12 h. The results showed that NGR had the function of good targeting.