The contrast medium ICG is excreted by liver and its excretion time in tumor cells is different from that in normal cells. ICG will be nearly exclusively excreted in normal liver cells in 7 days after intravenous injection prior to surgery while it cannot be excreted in tumor cells. Liver tumors can be detected by using fluorescence-guided imaging technology of which the detection rate of subcapsular lesions is higher than by preoperative imaging and by intraoperative ultrasonography.