Recent advances in PET probes for hepatocellular carcinoma characterization.

INTRODUCTION: Positron Emission Tomography (PET) with 18F-fluorodeoxyglucose (FDG) presents some limitations for imaging of hepatocellular carcinoma (HCC), the most common primary hepatic malignancy. AREAS COVERED: The authors discuss the accuracy and limitations of FDG for HCC detection. Then, authors examine the recent advances in PET tracers other than FDG for the biological and prognostic characterization of HCC such as 11C-acetate, 11C-choline, and its 18F-labeled derivatives. EXPERT COMMENTARY: FDG PET can be helpful for the identification of the more aggressive and poorly differentiated HCC. 11C-acetate is readily incorporated into intracellular phosphatidylcholine membranes and proved useful for the in vivo biological characterization of the more differentiated and less aggressive HCC. Nevertheless, the short half-life of 11C- radionuclide limits the clinical application of this compound. 11C-choline, another surrogate biomarker of cell membrane biosynthesis, has been demonstrated effective for HCC imaging. The availability of choline derivatives labeled with 18F-radionuclide (i.e. 18F-fluoroethylcholine, 18F-fluorocholine) has overcome the drawbacks due to 11C, thus triggering the clinical applications of choline PET for HCC diagnosis and management. Further research needs to be conducted to better define the alternative or complementary role of these PET probes for the characterization of HCC, with particular regard to the dual-tracer PET-CT modality.