Preoperative examination and preparation: ask for detailed medical history, read the preoperative CT and MRI films carefully, strictly abide by the operation standard and diagnosis and treatment guideline of tumor ablation therapy, correctly grasp the indications and contraindications of tumor ablation therapy, and decide on the treatment plan according to the patient’s condition, optional treatment means, and patient’s financial capacity. Before the implementation of tumor radiofrequency ablation therapy, the patients and their families should be informed of the purpose of the treatment, the risk of the treatment, the precautions to be taken after the treatment, the possible complications and the preventive measures, etc., and sign the informed consent. Zheng Zhaomin, Department of Minimally Invasive Oncology, Thousand Buddha Mountain Hospital, Shandong Province (1) Preoperative evaluation and laboratory examination of patients: tumor patients with ECOG score of 3 or less. Review blood routine, blood type, liver and kidney function, and complete set of blood clotting time. (2) Other preoperative examinations: mainly include monitoring vital signs such as blood pressure and pulse, receiving routine chest X-ray (to observe the presence or absence of emphysema and pleural hypertrophy) and electrocardiogram, abdominal ultrasound and other examinations. If clinical considerations need to go through the lung for radiofrequency ablation treatment of tumors in the hepatic area near the top of the diaphragm or in the lungs, the lung function should also be tested. (3) Preoperative preparation: fasting and water fasting for 6 hours before surgery. Empty the bladder before surgery. Prepare the intravenous indwelling needle and open the intravenous access. For highly nervous patients, ask them to relax, can take diazepam 10mg orally 1 hour before the operation. explain the purpose of radiofrequency ablation therapy to the patient, try to choose the supine position, avoid the oblique position. Breathing should be calm and closed at the end of inhalation. For those with significant cough that interferes with the operation, codeine 30mg should be taken 1 hour prior to the procedure. anticoagulant drugs (e.g. aspirin, etc.), if any, should be discontinued at least 72h prior to the radiofrequency ablation treatment. Intramuscular pethidine injection 75-100mg for analgesia 30 minutes to 1 hour before the procedure. (4) Preparation of items: radiofrequency treatment device (including cooling circulator), radiofrequency treatment needle, phlebotomy kit, ice, imipramine 5mg; 5ml syringe or 10ml syringe, 18G intravenous indwelling needle, 2% lidocaine, iodine and cotton swabs, adhesive tape, abdominal band, sphygmomanometer and stethoscope, sterile gloves. Have plasma or platelets available if necessary. The operating room should have oxygen, sputum, cardiac monitoring and defibrillator, ready to rescue drugs. 2.Operating method Emphasize that the operation should be guided by imaging technology to ensure the safety, accuracy and effectiveness of treatment. The scope of ablation should strive to include the paracancerous tissues over 0.5 cm, so as to obtain the “safe edge” and kill the tumor completely. For invasive cancer or metastatic cancer with unclear boundary and irregular shape, it is recommended to expand the peritumor safety margin to 1 cm or more if the adjacent liver tissues and structural conditions permit. The operation steps are as follows: (1) Choose the supine position as much as possible. Connect the radiofrequency wire and electrode plate between the electrode and the host computer, and routinely apply the electrode film to the hairless part of both thighs before the operation. (2) Routine disinfection of the skin, laying a sterile cavity towel, 2% lidocaine local anesthesia should reach the hepatic peritoneum. When it is estimated in advance that radiofrequency ablation may cause moderate to severe pain, it is strongly recommended that it be performed under intravenous anesthesia to ensure that radiofrequency ablation is performed smoothly. (3) It must be performed under image guidance and monitoring, and can be repeated several times to treat multiple lesions; the patient’s condition should be closely observed during the treatment, so that possible complications can be detected in time. (4) During the process of radiofrequency ablation, vital signs should be monitored; generally, a treatment process takes about 8 to 12 minutes, and larger lesions need to be maintained for 24 minutes or even longer; the ablation will be stopped automatically at the scheduled time; after the ablation is completed, the ablation of the needle tract should be carried out when the needle is withdrawn, so as to prevent postoperative hemorrhage and planting of the tumor along the needle tract; it is decided whether to ablate the other locations according to the situation. (5) In the process of tumor ablation treatment, it should be closely observed whether there are complications such as internal bleeding, pneumothorax, gastrointestinal perforation and so on. Evaluation and follow-up of the efficacy of radiofrequency ablation Establish and improve the technical evaluation and follow-up system of radiofrequency ablation therapy for tumors, and record according to regulations. The necrosis of the lesion should be regularly observed after ablation treatment, and if there is any residual lesion, remedial treatment should be actively carried out to improve the efficacy of radiofrequency ablation treatment. The standard method to evaluate the local efficacy is to use contrast-enhanced CT/MRI or ultrasonography to determine whether the tumor has been completely ablated about one month after RF ablation. For patients with more iodine oil deposits in the lesion, MRI can be used, which can avoid the artifacts of iodine oil and is more accurate than CT. Lesions with complete ablation show no blood supply, i.e., no enhancement. If ablation is incomplete, remedial therapy may be given. If complete ablation cannot be obtained after 3 ablations, ablation therapy should be abandoned and other treatments should be used. Precautions 1. If the liver function is not compensated and the coagulation time is significantly prolonged before the operation, plasma should be prepared, and platelets or coagulation factors should be transfused if necessary. For cirrhotic patients with coagulation disorders, a small dose of recombinant factor VIIa should be given; for patients with platelet count <50000/mm3, PT prolongation >4 seconds, and hepatic dysfunction, plasma and platelet transfusion can be used to correct the situation. 2. Before the operation, patients should be trained to hold their breath several times in advance to cooperate with the operation. The radiofrequency treatment needle should not be stirred after entering the liver. 3. Vital signs should be routinely monitored within 12 hours after surgery, first every 30 minutes to 1 hour, and then every 2 hours if stable. If the blood pressure drops during the period and there are signs of bleeding, the use of hemostatic drugs, blood transfusion (such as concentrated red blood cells, plasma or platelets) should be considered, and if necessary, surgical consultation should be requested for surgical exploration. 4. Patients with cardiac valvular diseases or those with the risk of bacteremia need to be given antibiotics prophylactically; if intraoperative transpulmonary treatment of liver tumors on the top of the diaphragm or lung tumors, preoperative prophylactic antibiotics and postoperative antibiotic treatment can be used. 5. Patients should not move their bodies during radiofrequency treatment, which is important to complete the procedure and minimize complications. 6. Patients with cardiac pacemaker should be under close cardiac monitoring. 7. patients should be asked to avoid heavy labor and strenuous physical activities etc. for one week after the operation. 8. Informed consent must be signed. Radiofrequency ablation therapy has the following risks: anesthesia accidents such as cardiac arrest, allergic reaction, etc.; radiofrequency treatment site bleeding, liver rupture, pneumothorax, shock, infected or bloody pleural effusion; damage to nerves, kidneys, adrenal glands, pancreas, etc.; damage to the stomach, the colon caused by perforation may be; biliary fistula, cholestatic peritonitis, liver abscess; electrode skin burns; radiofrequency ablation treatment failure, needle channel implantation metastasis, postoperative recurrence possible ; portal vein embolism after radiofrequency is a major cause of death, especially seen in patients with cirrhosis. and other unforeseen accidents. 9. Prevention and treatment of several common complications: (1) vagal reflex: the vagal reflex produced by radiofrequency heat production on the hepatic peritoneum and intrahepatic vagus nerve stimulation can cause slow heart rate, arrhythmia, drop in blood pressure, and in severe cases, it can lead to death. Preoperative atropine or scopoletin can be given for prevention. If vagal reflex occurs during operation, atropine or scopoletin can be given. (2)Injury of intra- and extra-hepatic bile ducts:Radiofrequency thermocoagulation of hepatocellular carcinoma in the first hepatoportal region should avoid injuring the larger bile ducts, so the range of thermocoagulation should not be too large. (3) Injury to perihepatic cavity organs: especially for those who have a history of surgery or imaging examination found that the tumor invades the surrounding cavity organs, radiofrequency thermo-coagulation should be especially cautious to prevent serious complications such as internal or external fistulae caused by injuring the cavity organs in order to completely thermo-coagulate the tumor. (4) Internal hemorrhage: for liver tumors that are close to the liver surface or protruding out of the liver, puncture should not be made from the surface of the tumor, but should be made through the non-tumor liver tissue and then into the tumor tissue. Intraoperative and postoperative hemostatic drugs need to be given, and the abdominal bandage with chest and abdominal compression bandage should be given immediately after treatment. (5) Pneumothorax: avoid penetrating into the thoracic cavity as much as possible under the guidance of ultrasound during the operation, observe whether the breathing is stable after the operation, if there is respiratory difficulty, emergency chest X-ray should be given to make a clear diagnosis, a small amount of pneumothorax with stable respiration can wait for self-absorption, if the lung compression is more than 30% or the respiratory difficulty is obvious, closed drainage of the thoracic cavity should be given immediately.