[¹⁸F]Fluoroacetate Positron Emission Tomography for Hepatocellular Carcinoma and Metastases: An Alternative Tracer for [¹¹C]Acetate?

Abstract

[11C]Acetate (ACT) positron emission tomography/computed tomography (PET/CT) is useful in the detection of hepatocellular carcinoma (HCC). This study aimed to evaluate whether [18F]fluoroacetate (FAC) could be an alternative analogue of [11C]ACT for the diagnosis of HCC. [18F]FAC was synthesized using the precursor t-butyl 2-(methanesulfonyloxy)ethanoate. Five volunteer patients with known HCC were recruited after consent. Whole-body [18F]FAC PET/CT was performed at 20 minutes and 1 hour postinjection and compared to [11C]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. [18F]FAC was obtained with 99% radiochemical purity, and the reaction yield was 16.0% with 1-hour synthesis time. The biodistribution of [18F]FAC on PET/CT was significantly different from that of [11C]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 [11C]ACT-avid HCC lesions showed increased [18F]FAC activity. These were different from the results reported on other species. [18F]FAC may not be a potential alternative tracer for [11C]ACT in PET/CT evaluation of HCC in human subjects.

Utility of [18F]FSPG PET to Image Hepatocellular Carcinoma: First Clinical Evaluation in a US Population

“…In this scenario, [ 11 C]acetate PET/CT was collected prior to [ 18 F]FSPG PET/CT, with approximately 2 h in between the injections. [ 11 C]acetate imaging was conducted similarly to previously reported methods [12]. Twenty minutes following intravenous administration of [ 11 C]acetate (7.4 MBq/kg body weight), the patient was positioned on the imaging table, and a whole body (vertex of the skull to mid-thigh) transmission CT scan acquired (~90 s) followed by a whole body (vertex of the skull to mid-thigh) PET scan at 4 min/bed position (~40 min).…”

Positron Emission Tomography Imaging of Tumor Cell Metabolism and Application to Therapy Response Monitoring

“…[ 18 F]Fluoroacetate ([ 18 F]FACE), a [ 18 F]fluorinated acetate analog (t1/2: 110 min), which is putatively converted to fatty acids and incorporated into lipids, has been tested as an alternative PET tracer for imaging fatty acid synthesis. However, there are only limited clinical reports using [ 18 F]FACE for oncologic diagnosis of patients with cancer ( 103 , 104 ), thus far with no studies evaluating therapy response.…”

Functional imaging of hepatocellular carcinoma

“…While encouraging, subset analysis revealed a significantly lower sensitivity (32%) for the detection of small HCC lesions (1-2 cm). 18 F-acetate was studied as an alternative to 11 C-acetate due to its longer half-life (110 vs 20 min) and more favorable biodistribution [106]. However, no difference was observed in the uptake of 18 F-acetate by the tumorcompared with 18 F-FDG [107].…”