“Gamma knife” named “knife”, but is not a real scalpel, it is a modern radiation physics, radiation biology, medical imaging, computers, intelligent automation control and other disciplines in one, in order to treat human cranio-cerebral diseases, mainly large high-tech Radiosurgery treatment equipment. Gamma knife is also known as stereotactic gamma radiation therapy system. Its basic principle is the use of three-dimensional stereotactic technology to precisely locate the lesion in the skull, the gamma rays will be precisely focused irradiation to the lesion, a one-time high dose to destroy the lesion tissue, to achieve the effect similar to surgical excision. Because of the gamma radiation irradiation lesion and the surrounding normal tissue boundary sharp as a knife cut, so the image is called “gamma knife”. Gamma knife through the CT and magnetic resonance and other modern imaging technology is precisely located in a certain area, we call the “target point”. Gamma knife positioning is extremely accurate, the error is often less than 1.0 mm. Therefore, Gamma Knife has the advantages of small trauma, short hospitalization time, fast recovery, cost saving, low risk and complications. Gamma knife is divided into head gamma knife and body gamma knife. The head gamma knife is a multiple cobalt source installed in a spherical helmet, so that it is focused on a point in the skull, forming a narrow beam of sharp-edged gamma rays. During treatment, the narrow beam of rays is converged on the lesion to form a limited high-dose area to destroy the lesion, mainly used for the treatment of small intracranial tumors and functional diseases. Body Gamma Knife is mainly used to treat various tumors throughout the body. Brain actinomata, cavernous hemangiomas, pituitary tumors, metastases, auditory neuromas, meningiomas, postoperative residual intracranial tumors, trigeminal neuralgia, etc. can all be treated with Gamma Knife.