●What areas of tumors can be treated with the radio wave knife? What are the clinical advantages of the radiofrequency knife? Radiofrequency knife can treat tumors in all parts of the body. According to the recommendation of AAPM 101, the best indications are that the tumor envelope is intact, the boundary is clear, and the diameter does not exceed 5cm. Tumors close to important organs, such as the eye, brainstem, spinal cord, etc., where ordinary radiation therapy is difficult to implement and ineffective; complex tumors located in complex tissues and organ structures, which are difficult to be removed by surgery; multiple metastases requiring simultaneous treatment; tumors that have recurred after radiation therapy or tumors that require additional doses can be treated with radiofrequency knife. Currently, the radio wave knife is widely used in intracranial lesions, head and neck lesions, spinal cord vertebral lesions, chest tumors, abdominal tumors, and pelvic tumors. For brain tumors such as meningiomas, gliomas, auditory neuromas, metastases, craniopharyngiomas, pituitary tumors, etc., traditional surgery is difficult, risky, prone to recurrence, and difficult to treat radically. Clinical applications have shown that the radiofrequency knife can kill tumors with great precision and also does not harm the surrounding healthy tissues. In the field of conventional radiation therapy, the treatment of tumor displacement generated by breathing is one of the biggest difficulties in current radiation therapy. Tumors in the chest and abdomen, such as lung (Figure 32), liver, and retroperitoneal metastatic tumors, are often displaced due to the influence of breathing movement. The breath tracking system of radio wave knife can more accurately track the movement of thoracic and abdominal tumors with breathing, control the radiation dose reaching thoracic and abdominal tumors, and reduce the radiation dose to nearby healthy tissues, which has good effect on treating liver, lung and pancreatic cancer. However, it is not suitable for the initial treatment of some cavity organ tumors such as esophageal cancer, gastric cancer, rectal cancer and head and neck tumors such as nasopharyngeal cancer with the radiofrequency knife.