2-Deoxy-2-[18F]Fluorosorbitol (18F-FDS) as a Potential PET Tracer for Renal Imaging and GFR Measurement: Comparative Assessment with 68Ga-EDTA and 99mTc-DTPA

Background Accurate assessment of glomerular filtration rate (GFR) is critical for monitoring renal function. This study aims to evaluate its feasibility as a PET radiopharmaceutical for renal imaging and GFR assessment. Its novelty lies in the direct, head-to-head comparison with 68Ga-EDTA and 99mTc-DTPA to comprehensively assess the potential advantages and translational relevance of 18F-FDS for clinical GFR measurement. Methods 18F-FDS was synthesized via a reduction reaction, and its radiochemical purity was evaluated using radio-TLC. In vitro stability was assessed for up to 4 hours. Plasma protein and erythrocyte binding rates of 18F-FDS, 68Ga-EDTA, and 99mTc-DTPA were determined to evaluate their pharmacokinetic suitability for renal imaging. Dynamic and static renal imaging was performed in healthy male Wistar rats. Time-activity curves were generated to calculate Tmax, biological half-life (T1/2), normalized residual activity (NORA), and GFR. Results 18F-FDS was synthesized with a radiochemical purity exceeding 98% and demonstrated high in vitro stability over 4 hours. Plasma protein binding and erythrocyte of 18F-FDS was lower than for all radiopharmaceuticals. Dynamic small-animal imaging revealed rapid renal uptake and efficient urinary excretion for all agents. No statistically significant differences were observed in GFR values or kinetic parameters derived from 18F-FDS and 68Ga-EDTA imaging (p > 0.05). Conclusions The favorable in vitro characteristics and renal kinetic profiles of 18F-FDS support their potential use as PET radiopharmaceuticals for renal imaging and GFR quantification. In particular, the low plasma protein binding and comparable GFR measurements suggest that 18F-FDS may serve as a promising alternative to established tracers for functional renal assessment.