A Prospective Evaluation of 18F-FDG and 11C-Acetate PET/CT for Detection of Primary and Metastatic Hepatocellular Carcinoma

90 patients with primary HCC were 60.9%, 75.4%, and 82.7%, respectively. Elevated serum a-fetoprotein levels, an advanced tumor stage, portal vein tumor thrombosis, large tumors, and multiple tumors were significantly associated with positive 18F-FDG PET/CT results. Uptake of 11C-acetate was associated with large and multiple tumors. For 18 F-FDG, the sensitivities according to tumor size (1‐2, 2‐5, and $5 cm) were 27.2%, 47.8%, and 92.8%, respectively; for 11 C-acetate, these respective values were 31.8%, 78.2%, and 95.2%. 18 F-FDG was more sensitive in the detection of poorly differentiated HCC. Overall survival was lower in patients with 18 F-FDG PET/CT positive for all indexed lesions than in those with FDG negative or partially positive through the entire follow-up period. In analysis based on biopsied lesions, the sensitivity of 18F-FDG PET/CT was 64.4% for primary HCC and 84.4% for 11 C-acetate PET/CT. The overall sensitivities of 18F-FDG, 11C-acetate, and dual-tracer PET/CTfor35metastaticHCCswere85.7%,77.0%,and85.7%, respectively. There was no significant difference in the sensitivity of tracers according to metastatic tumor size, location, or differentiation. Conclusion: The addition of 11C-acetate to 18F-FDG PET/CT increases the overall sensitivity for the detection of primary HCC but not for the detection of extrahepatic metastases. 18 F-FDG, 11 C-acetate, and dual-tracer PET/CT have a low sensitivityforthedetectionofsmallprimaryHCC,but 18 F-FDGPET/CT has a relatively high sensitivity for the detection of extrahepatic metastases of HCC.