Hepatocellular carcinoma is the most common primary tumor in the liver. FDG PET has been applied for staging and treatment planning of hepatocellular carcinoma. It could reflect tumor prognosis because glucose metabolism assessed by FDG PET is known to have correlations with the differentiation and aggressiveness of the tumor. Although the ability of FDG PET to detect well-differentiated or low grade tumors and intra-hepatic lesions is not good, it is expected to play a major role in pre-surgical assessments for liver transplantation because it is useful in detecting extra-hepatic lesions and unexpected distant metastases with a better diagnostic performance than other conventional imaging modalities. Additionally, FDG PET has an advantage to screen other cancers through whole body scanning. As a new tracer for PET, Acetate demonstrates higher sensitivity and specificity to FDG in evaluating hepatocellular carcinoma. It thus seems that simultaneous use of Acetate PET with FDG PET could be helpful in diagnosis, especially detecting extra-hepatic metastases. (Nucl Med Mol Imaging 2008;42(suppl 1):60-65)