The most common brain tumors are metastatic and primary malignant tumors (e.g., astrocytoma) or benign tumors (e.g., meningioma, auditory neuroma). Surgery and chemotherapy are the most widely used treatments for brain tumors, but in recent decades, radiation therapy and radiosurgery have become important treatment options for brain tumors. The goal of radiosurgery is to relieve symptoms, control localized tumors, and thereby prolong the life of the patient. 1. Due to the high recurrence rate of resected malignant tumors, brain tumor surgery is mostly performed after conventional radiation therapy. Radiofrequency knife can provide patients with tumor-only radiation therapy after brain tumor surgery, without affecting patients’ health as conventional radiation therapy does. The non-isocentric delivery of the radiation beam (i.e., the beam does not need to be concentrated at a single point) allows the dose distribution to smooth out irregularly shaped tumors.3. The accuracy of the radio wave knife is less than 1 mm, allowing the system to deliver high doses of radiation without damaging vital body structures. 3. The stentless and non-invasive radiosurgery of the radio wave knife can be used for single or multiple radiation treatments, and the dose can be delivered in 2 to 5 doses to reduce the impact of damage to sensitive structures such as brain nerves and eyes. 4. The safety and effectiveness of the radiofrequency knife in the treatment of intracranial malignant lesions are well known. Published literature shows that this system can control tumors in the majority (91%) of patients with intracranial tumors and has a low rate of complications. 5. The radiofrequency knife is also effective in treating benign intracranial tumors. The tumor control rate is 97% and the hearing preservation rate is 74% in 61 patients with auditory neuroma treated from 1991 to 2001. 6. Staged radiosurgery with the radiofrequency knife is also effective in patients with paraneoplastic tumors. High tumor control rate (94%) and visual preservation (94%) were also observed in 49 consecutive patients.