Abstract: Objective To investigate the tumor targeting efficacy of 18F-AlF-NOTA-PRGD2, a novel radiotracer of
Arginine-glycine-aspartic acid (RGD) peptides. Methods 18F-AlF-NOTA-PRGD2 was synthesized in one-step by conjugating
NOTA-RGD2 with 18F-AlF at 100 ℃. The tumor targeting efficacy and in vivo biodistribution profile of 18F-AlF-NOTA-RGD2,
following intravenous injection via the tail vein, were evaluated in a nude mouse model bearing subcutaneous U87MG
glioblastoma xenograft by radioactivity biodistribution assessment, PET/CT and microPET/CT. Results NOTA-RGD2 was
18F-fluorinated successfully in one-step with a yield of 17%-25% within 15-20 min. Radioactivity biodistribution study
confirmed the tumor-targeting ability of 18F-AlF-NOTA-PRGD2 in the tumor-bearing mice. At 1 and 2 h following injection,
18F-AlF-NOTA-PRGD2 uptake in the tumor reached 4.14±1.44 and 2.80±1.18 % ID/g (t=1.910, P=0.070) with tumor/brain ratios of
2.95 ± 0.61 and 5.21 ± 2.62, respectively (t=-1.686, P=0.167). Both PET/CT and microPET/CT were capable of showing the
radioactivity biodistribution of 18F-AlF-NOTA-PRGD2 in the mouse model and clearly displayed the tumor, but microPET/CT
showed a much better image quality. Conclusion 18F-AlF-NOTA-PRGD2 prepared by one-step radiosynthesis can selectively
target to the tumor, demonstrating its potential as a good radiotracer for tumor imaging.