Ex-vivo biodistribution and micro-PET/CT imaging of 18F-FDG, 18F-FLT, 18F-FMISO, and 18F-AlF-NOTA-PRGD2 in a prostate tumor-bearing nude mouse model.

OBJECTIVE: (18)F-Fluorodeoxyglucose ((18)F-FDG), (18)F-fluoro-3'-deoxy-3'-L-fluorothymidine ((18)F-FLT), (18)F-fluoromisonidazole ((18)F-FMISO), and (18)F-AlF-NOTA-PRGD2 ((18)F-RGD) are all commonly used PET tracers for tumor diagnosis based on different mechanisms of tissue uptake. This study compared the ex-vivo biodistribution and PET/computed tomography (CT) imaging studies of these four PET tracers in a xenograft prostate tumor-bearing mouse model.

MATERIALS AND METHODS: Nude mice were inoculated with 5 × 10 PC-3 cells in the right armpit. The ex-vivo biodistribution of (18)F-FDG, (18)F-FLT, (18)F-FMISO, and (18)F-RGD at 30, 60, 90, and 120 min after injection was compared. Micro-PET/CT images of (18)F-FDG, (18)F-FLT, and (18)F-RGD were acquired at 60 min, whereas (18)F-FMISO images were acquired at 90 min after injection.

RESULTS: The tumors were clearly visualized by micro-PET/CT using all four PET tracers. Ex-vivo biodistribution results showed highest tumor accumulation and tumor-to-muscle ratio of (18)F-FDG at each time point, accompanied by physiologically high uptakes in the brain, heart, and intestinal tract. Modest uptake of (18)F-FLT and (18)F-FMISO in tumors was observed at 60 and 90 min after injection, with less interference from other tissues compared with (18)F-FDG. Besides, (18)F-RGD also exhibited high tumor specificity; however, relatively low uptake was observed in the tumor.

CONCLUSION: Our results demonstrated the potential of (18)F-FMISO and (18)F-FLT in the diagnosis of xenograft prostate cancer.