Gamma Knife Treatment Principle: Stereotactic Gamma Ray System (Body Gamma Knife) is a kind of stereotactic radiotherapy equipment integrating stereotactic and surgical techniques to treat body diseases. It adopts the geometric focusing method of gamma rays, and through precise stereotactic orientation, a certain dose of gamma rays is planned to be irradiated on the pre-lighting target point, so that the tumor tissues can be irradiated in multiple fields and angles, and the radiotherapy is carried out in accordance with the different shapes and sizes of the tumors. The treatment volume is basically equal to the volume of the lesion (i.e. “target”), which can lethally destroy the tumor tissues in the target point, or through the accumulation of high energy gamma rays in the target area of the tumor to form the accumulation of radiation, gradually reaching the lethal member of the tumor tissues to kill the diseased tissues, in order to achieve the effect of surgical resection or destruction of the tumor. Due to the way of rotating radiation aggregation, the radiation passing through the human body and normal tissues is only subjected to instantaneous, almost harmless irradiation, and the radiation outside the target point is sharply reduced, so its therapeutic irradiation range is very clear with the boundaries of normal tissues, and the edge of it is like a knife, which is imaginatively known as the “Gamma Knife”. What is the clinical application of Gamma Knife therapy? Radiation therapy plays an important role in the comprehensive treatment of cancer. In China, more than 70% of patients with malignant tumors require radiotherapy at different stages of their disease. However, since the efficacy of traditional radiotherapy depends on the sensitivity and repair ability of tumor tissues and surrounding healthy tissues to rays, the unnecessary irradiation of healthy tissues around the tumor by conventional radiotherapy has become a major constraint to increase the dose to the target area. In recent years, three-dimensional conformal radiotherapy technology has rapidly matured, which can conform the radiation high-dose area (irradiation field) to the tumor (target area) and improve the dose rate of the target tissues, resulting in a high dose to the target area and a low dose to the surrounding tissues (the target center should be more than 50% higher than the peripheral dose). Single or multiple high-dose irradiation can achieve the purpose of killing the tumor or locally controlling the tumor. High-dose fractionated irradiation is more consistent with radiobiological principles than single irradiation. “Precision Radiation Therapy” is considered by the radiation oncology community as the development direction of today’s radiation therapy, and is the mainstream of the development of radiation therapy technology. Indications of Gamma Knife I. Cranio-cerebral diseases 1. Various types of cranio-cerebral tumors: pituitary tumor, acoustic neuroma, meningioma, craniopharyngioma, chordoma, brain metastases, glioma, nasopharyngeal carcinoma and other benign and malignant tumors of the head of the eyes, ears and nose, etc. 2. Cerebral vascular malformations: cerebral arterio-venous malformations and cerebral cavernous angiomas. 3. Functional cerebral neuralgia diseases: trigeminal neuralgia, epilepsy, Parkinson’s disease, malignant pain and refractory mental illnesses, etc. 2. Body diseases 1. primary lung cancer and lung metastatic cancer; 2. primary liver cancer and liver metastatic cancer; 3. esophageal cancer, mediastinal tumors; 4. pancreatic cancer, gallbladder cancer, bile duct cancer; 5. rectal cancer, bladder cancer, prostate cancer; 6. metastatic tumors of lymph nodes in hilar, mediastinal, abdominal and pelvic cavities, etc.; 7. renal and adrenal cancer; 8. gynecological tumors. Superiority of Gamma Knife: 1. No incision, no bleeding, no pain. Gamma Knife adopts stereotactic technology to focus high-energy rays on the target area to achieve the purpose of treatment without incision, general anesthesia, and the patient stays awake during the treatment process, and can even eat and drink, so there is no pain; 2. Simple and time-saving. Gamma Knife treatment of brain tumors only takes 2~3 hours, the real implementation of ray irradiation only takes a few minutes to dozens of minutes, usually before and after the treatment can be hospitalized for 1~2 days; 3, high precision, small damage. Gamma Knife is a high-tech product, its therapeutic error is only 0.1~0.3mm, so there is almost no damage to normal tissues around the tumor when treating brain tumors, which avoids the risk of hemorrhage and hemiplegia that may be brought about by open surgery; 4. For the old and frail patients, as well as patients suffering from high blood pressure, heart disease and diabetes, who can not tolerate the surgical treatment, the treatment with Gamma Knife has obviously increased the security of the treatment.