The Gamma Knife is not really a scalpel, but a very advanced radiation therapy device with the full name: Gamma Ray Stereotactic Therapy System. It shines many narrow beams of gamma rays through the body from different angles and directions and causes them all to converge at one point to form a focal point. The principle of Gamma Knife treatment is similar to the process of focusing a magnifying glass. When a magnifying glass is placed in the sunlight, a bright and eye-catching class of light, the focal point, is formed underneath the magnifying glass. Beyond the focal point, the person feels as normal, but at the focal point there is a high level of heat, enough to set some objects on fire. Of course, to focus in the human body, with the sun’s rays is impossible, and must be used with penetrating high-energy rays such as gamma rays; at the same time, to make gamma rays focus is not as simple as a magnifying glass to focus, and the comprehensive use of nuclear physics, computers, bio-radiology, electromechanical and a series of modern technology to achieve. Gamma Knife treatment, the first three-dimensional positioning system for diagnosis and localization of the lesion, three-dimensional positioning system is a special coordinate system, the patient in the three-dimensional positioning system is relatively fixed, through the CT/MRI tomography scan of the lesion can show the lesion and the coordinate system of the relative position of the reference points. After diagnosis and positioning, the treatment planning system automatically processes the CT/MRI scanning pictures, computer reconstructs the three-dimensional morphology of the body surface, the lesion and its surrounding sensitive tissues, and carries out the treatment planning based on the prescription dose prescribed by the doctor, calculating the number of target points required for treatment, the coordinates of the target points, the collimator number and irradiation time to be used for each target point, and so on. After receiving the relevant data from the treatment planning system, the electrical control system controls the treatment bed to deliver each target point to the focal point in sequence and turn on the corresponding collimator for quantitative irradiation to achieve the purpose of tumor treatment. Treatment scope of head gamma knife 1, cerebrovascular disease: intracranial arteriovenous malformation, intracranial arteriovenous tumor, cavernous hemangioma. Intracranial tumors: acoustic neuroma, meningioma, pituitary adenoma, pineal region tumor, craniopharyngioma, brain stem tumor, embryonal tumor, brain metastasis tumor, glioma, chordoma, etc. Especially tumors located in the functionally dense area and with greater surgical risk. Nasopharyngeal cancer: ocular melanoma and other benign and malignant tumors of the eye. Functional neurological diseases: intractable pain, Parkinson’s disease, epilepsy, primary trigeminal neuralgia and so on. 5.Some postoperative residuals that have not been removed cleanly by conventional craniotomy.