Objective: Hepatocelluar carcinoma (HCC) has a high recurrence rate even after curative resection.Rising AFP levels often occur even when conventional imaging studies and clinical examination are normal.The preliminary data are promsing for the use of FDG-PET as an indicator of tumor viability after therapy.The aim of this study was to evalute the value of 18F-FDG PET/CT in investigating HCC with unexplained serum AFP elevation following by surgical resection, transarterial chemoembolization (TACE) or radiofrequency ablation (RFA).Methods: A retrospective study was conducted involving 17 HCC patints (13 men, 4 women;mean age at diagnosis, 57 years; range, 28-80 years) who underwent 18F-FDG PET/CT for evaluation of AFP without evidence of HCC recurrence.The 18F-FDG PET/CT results were correlated with histological findings, as well as long-term radiological and clinical follow-up (shortest follow-up period after FDG-PET was 6 months).Results: Among the 17 patients, 12 patients demonstrated HCC recurrence(6 interahepatic,3 extrahepatic and 3 interahepatic/extrahepatic).Metastatic foci were found in the lymph node(3 patients), bone(1 patient), lung and muscle(1 patient), lung and crura of diaphragm (1 patient).The 18F-FDG PET/CT indentified 7 interahepatic and 6 extrahepatic.Overall, the 18F-FDG PET/CT had 10 true-positives, 3 false-negatives,4 true-negatives and zero false-positives for the detection of HCC recurrence.The sensitivity, pecificity, positive predictive value and negative predictive value were 77%、 100%、 82%、 100%、 57%, respectively.Conclusions: When conventional examinations are normal, the 18F-FDG PET/CT is a valuable imaging tool in patients who have rising AFP levels after HCC treatment.