To evaluate the safety and efficacy of ultrasonography (US) -guided radiofrequency ablation
for liver tumors, the investigators used preoperative and postoperative
US/CEUS(contrast-enhanced ultrasonography)/CT/MRI to assess lesions, and laboratory tests
including the tumor markers to evaluate the general condition of patients. Intraoperative
US/CEUS/CT would be applied to monitor ablation lesions.