MicroPET imaging with 2-[18F]fluoropropionic acid in Lewis lung carcinoma-bearing mice

Abstract

Objective To prepare 2-[18F]fluoropropionic acid (18F-FPA) and evaluate its biodistribution and imaging capacity in Lewis lung carcinoma-bearing mice. Methods 18F-FPA was prepared by nucleophilic substitution reaction, and its hydrophilicity was analyzed. 18F-FPA (7.4-11.1 MBq) was injected into Lewis lung carcinoma-bearing mice via tail vein. MicroPET imaging was performed at 20, 80 min after the injection. The biodistribution of 18F-FPA in organs was analyzed. The blocking effects of sodium propionate and dichloroacetate to 18F-FPA were tested in vivo. Data were analyzed by two-sample t test using GraphPad Prism software. Results The synthesis of 18F-FPA took 40 min. 18F-FPA had high radiochemical purity (>99%) and hydrophilicity. 18F-FPA was mainly distributed in the carcinoma, the urinary bladder and the caecum. The radioactive uptakes in muscles, brown fat and bones were relatively low. Quantitative analysis showed that the uptake of 18F-FPA in Lewis lung carcinoma from 20 min to 80 min was slightly increased ((17.03±2.87) %ID/g vs (19.33±2.45) %ID/g) without significant difference (t=1.100, P>0.05). Neither sodium propionate nor dichloroacetate could block the uptake of 18F-FPA in Lewis lung carcinoma (t=1.544, 0.894; both P>0.05). Conclusions 18F-FPA can be quickly synthesized and has good physicochemical properties. It can be used as a tracer to visualize Lewis lung carcinoma in mice, and its tumor uptaking can not be blocked by propionate and dichloacetate. 18F-FPA PET has the potential to detect lung cancer noninvasively in clinic. Key words: Propionic acids; Isotope labeling; Fluorine radioisotopes; Tomography, emission-computed; Tomography, X-ray computed; Lung neoplasms; Mice