Gamma knife is a device for radiosurgery, invented by Professor Lekcell of Sweden, is the use of focused gamma rays, through 192 rays focused to a point, which produces a high radiation dose, with this high radiation dose point to irradiate tumors or vascular malformations, or some functional lesions, to achieve the purpose of treating cranio-cerebral diseases, this a radiosurgery device. It is the gold standard of radiosurgery treatment at present. The scope of treatment mainly includes cranial tumors, various vascular malformations, functional diseases, such as trigeminal neuralgia, including epilepsy, obsessive-compulsive disorder, these functional diseases, can achieve the effect of an excellent neurosurgeon surgery to treat cranial diseases, in the clinical area it is called Gamma Knife.