Principle of Tumor Radiofrequency Ablation Tumor radiofrequency ablation (RFA) refers to the placement of unipolar or multipolar electrodes into the tumor tissue, through the electrode emits frequent changes of high-frequency alternating current, so that the conductive ions or polarized molecules within the tissue cells rapidly change direction, and generate heat energy by mutual oscillation and friction, resulting in a local temperature of the tissue of more than 60 ℃, and the tumor cells rapidly undergo protein denaturation and coagulation necrosis, so as to achieve the purpose of tumor treatment. Tumor cells rapidly undergo protein denaturation and coagulation necrosis, thus achieving the purpose of tumor treatment. With the progress of applied physics and the innovation of cold circulation technology, it can overcome the defects of various technologies of microwave ablation and become a new generation of ablation technology with easy manipulation of thermal field effect, larger ablation range and more effective treatment. In recent years, the complete ablation effect and safety in radiofrequency treatment of liver tumors have been significantly improved, and the progress has been more rapid, paving a promising road for minimally invasive treatment of liver cancer. Advantages of Radiofrequency Ablation for Liver Cancer Minimally invasive surgical advantages such as less pain, less trauma, faster recovery, fewer complications and shorter hospitalization time. However, the non-standard use of non-specialized doctors and the superficial understanding of radiofrequency technology in the past have made most of the tumors, even small liver cancers, fail to achieve the purpose of complete ablation, which directly affects the near- and long-term effects, and puts the efficacy of this technology into question. With the development of science and technology, the scope of ablation has been expanded and safety has been improved. For early primary small hepatocellular carcinoma on or near the surface of liver, expanding the scope of ablation treatment under the combined guidance of laparoscopy and intraoperative ultrasound can achieve comparable effect with surgical resection; (2) For tumors adjacent to liver blood vessels, bile ducts and other deep important structures, which are difficult or impossible to be removed by surgical resection, this technique shows its superiority, which can not only achieve the purpose of complete ablation, but also avoid the need for laparotomy, so that the efficacy of this technique can be questioned. It can not only achieve complete ablation of tumor, but also avoid serious complications such as abdominal bleeding, bile leakage, bile duct injury, abscess and organ perforation, liver failure, etc.; (3) The close combination of this technique with trans-femoral artery puncture hepatic artery chemoembolization (TACE) or simple embolization can further consolidate and improve the long-term efficacy of the ablation treatment for liver cancer in these special areas. Scope of application of radiofrequency ablation 1, patients with the desire to receive minimally invasive treatment with radiofrequency ablation; 2, single or multiple tumors less than 5cm in diameter or less than 3 foci with no distant metastasis; 3, poor liver reserve function, which makes it difficult or impossible to be resected by surgical resection; 4, patients who are unwilling or unable to receive liver transplantation; 5, patients with unsatisfactory efficacy after TACE; 6, tumors located on the surface of the liver or close to the surface, especially adjacent to the diaphragm and the liver artery, and especially adjacent to the diaphragm. The tumor is located at or near the surface of the liver, especially adjacent to the diaphragm, stomach and colon; 7. The tumor is located in the 1st and 2nd hepatic hilar, the caudate lobe, the right anterior and right posterior upper lobe (hepatic segments I/VII/VIII), the sagittal part of the portal vein, and adjacent to the inferior vena cava, and other important bile ducts and blood vessels of the special parts of the liver.