Abstract: Objective: To elucidate the correlations between pathological gross tumor volume (GTV), unenhanced CT GTV, the arterial-phase CT GTV and the portal venous phase CT GTV of hepatocellular carcinoma (HCC).Methods:Partici -pants included 11patients with histologically verified HCC who had undergone hepatectomy. Patients’surgical specimens and CT scans were obtained. All CT images were imported into the three-dimensional treatment planning system Philips ADAC Pinnacle 3 8.0. The radiological GTV were contoured on the unenhanced CT, arterial-phase images and portal ve -nous-phase images and the volumes were calculated with our RT planning system. After removing the specimens, they were sliced into parallel sections. All of the pathologic slices were scanned into a computer. The pathological GTVs were contoured on Adobe Photoshop CS 3 Extended software and the surfaces were calculated using the GTV delineated on the pathologic slices. The total pathological GTVs were calculated by integration. Results: The average volumes of pathological GTV, unenhanced CT GTV, arterialphase CT GTV and portal venous-phase CT GTV were 27.67± 24.84cm3 , 29.43± 26.83cm3, 28.13± 26.34cm3, and 28.57± 26.81cm3，respectively ( P>0.05). The coefficient of variation in tumors with and withoutcapsules was0.05± 0.02and 0.15± 0.08，respectively ( P=0.07). Conclusion:Radiological and pathological analysis of GTV yield similar results. In order to ensure all of the pathological GTVs allow for HCC without capsules, GTV on all phase CT images should be delineated and the largest GTVs chosen as the radiological GTV for planning.