Abstract: Objective The purpose of this study was to investigate the ¹⁸F-FDG PET/CT dual phase imaging in diagnosis of patients with different sizes of hepatocellular carcinoma （HCC）. Methods 40 patients with small HCC,40 with nodular HCC and 40 with giant HCC which were pathologically proved were retrospectively evaluated in this study. All patients underwent ¹⁸F-FDG PET/CT imaging by Siemens Biograph Turepoint 40 PET/CT. The maximum standard uptake values（SUVmax） were calculated based on semi-quantitative assessment. Results Out of 40 patients with small HCC,21 cases（52.5%）,of 40 with nodular HCC,24 cases （60%）,and of 40 with massive HCC,37 cases（92.5%） had the SUVmax in delayed phase increased as compared with the early phase（F=16.714,P=0.000）;The SUVmax of early phase and delayed phase in patients with small HCC were 3.99±1.40 and 4.17±1.99,respectively（t=-1.406,P=0.168）,the SUVmax of early phase and delayed phase in patients with nodular HCC were 5.04±1.87 and 5.23 ±2.25,respectively（t=-1.364,P=0.180）,and the SUVmax of early phase and delayed phase in patients with giant HCC were 6.98±2.57 and 8.10±3.11 respectively,and the difference in the latter group was statistically significant（t=-4.119,P=0.000）;There were statistical differences in the early phase of SUVmax values among the three groups （F=22.765,P=0.00）,and there were statistical differences in the delayed phase of SUVmax values among the three groups too（F=26.435,P=0.000）. Conclusion The diagnosis of HCC by dual phase PET/CT imaging is feasible in patients with large tumor mass.

Key words: Hepatocellular carcinoma, Computer tomography, Deoxyglucose