Comparison of three 18F-labeled carboxylic acids with 18F-FDG of the differentiation tumor from inflammation in model mice

Abstract

Background: The aim of this study was to compare the properties and feasibility of the glucose analog, 2-18F-fluoro-2-deoxy-D-glucose (18F-FDG), three short 18F-labeled carboxylic acids, 18F-fluoroacetate (18F-FAC), 2-18F-fluoropropionic acid (18F-FPA) and 4-(18F)fluorobenzoic acid (18F-FBA), for differentiating tumors from inflammation. Methods: Biodistributions of 18F-FAC, 18F-FPA and 18F-FBA were determined on normal Kunming mice, and positron emission tomography (PET) imaging with these tracers were performed on the separate tumor-bearing mice model and inflammation mice model in comparison with 18F-FDG. Results: Biodistribution results showed that 18F-FAC and 18F-FPA had similar biodistribution profiles and the slow radioactivity clearance from most tissues excluding the in vivo defluorination of 18F-FAC, and 18F-FBA demonstrated a lower uptake and fast clearance in most tissues. PET imaging with 18F-FDG, 18F-FAC and 18F-FPA revealed the high uptake in both tumor and inflammatory lesions. The ratios of tumor-to-inflammation were 1.63 ± 0.28 for 18F-FDG, 1.20 ± 0.38 for 18F-FAC, and 1.41 ± 0.33 for 18F-FPA at 60min postinjection, respectively. While clear tumor images with high contrast between tumor and inflammation lesion were observed in 18F-FBA/PET with the highest ratio of tumor-to-inflammation (1.98 ± 0.15). Conclusions: Our data demonstrated 18F-FBA is a promising PET probe to distinguish tumor from inflammation. But the further modification of 18F-FBA structure is required to improve its pharmacokinetics.