[F]Fluoroacetate Positron Emission Tomography for Hepatocellular Carcinoma and Metastases: An Alternative Tracer for [C]Acetate?

Abstract

[ 11 C]Acetate (ACT) positron emission tomography/computed tomography (PET/CT) is useful in the detection of hepatocellular carcinoma (HCC). This study aimed to evaluate whether [ 18 F]fluoroacetate (FAC) could be an alternative analogue of [ 11 C]ACT for the diagnosis of HCC. [ 18 F]FAC was synthesized using the precursor t-butyl 2-(methanesulfonyloxy)ethanoate. Five volunteer patients with known HCC were recruited after consent. Whole-body [ 18 F]FAC PET/CT was performed at 20 minutes and 1 hour postinjection and compared to [ 11 C]ACT PET/CT at 20 minutes postinjection to assess biodistribution and tumor uptake characteristics. Qualitative and semiquantitative analyses were performed with statistical correlations on the physiologic organs of accumulation and HCC lesions for both tracers. [ 18 F]FAC was obtained with 99% radiochemical purity, and the reaction yield was 16.0% with 1-hour synthesis time. The biodistribution of [ 18 F]FAC on PET/CT was significantly different from that of [ 11 C]ACT ( p < .05) by the lack of preferential uptake in any specific organ, particularly the pancreas, resembling the pattern of blood-pool retention although partly metabolized via the bowel. There was no significant defluorination, and none of the [ 11 C]ACT-avid HCC lesions showed increased [ 18 F]FAC activity. These were different from the results reported on other species. [ 18 F]FAC may not be a potential alternative tracer for [ 11 C]ACT in PET/CT evaluation of HCC in human subjects.