Al18F-1 was prepared in aqueous conditions using a one-pot Al18F-radiofluorination method and its radiochemical purity was determined by HPLC. Biodistribution studies, using 131I-OIH as an internal control, were performed in normal rats and in rats with renal pedicle ligation. In vitro stability and metabolism of Al18F-1 were analyzed by HPLC. Dynamic microPET/CT studies were conducted in normal rats.
Al18F-1 showed excellent stability in vitro and in vivo. Biodistribution studies in normal rats and in rats with simulated renal failure confirmed that Al18F-1 was exclusively cleared through the renal-urinary pathway and that the hepatic/gastrointestinal activity was less for Al18F-1 than for 131I-OIH both at 10 and 60 min. Dynamic PET showed a rapid transit of Al18F-1 through the kidneys into the bladder.
These results suggest that the easily labeled Al18F-based compounds provide a highly promising approach for the development of a PET renal radiotracer that combines superior imaging qualities with a reliable measure of effective renal plasma flow.