As the name suggests, Cranial Gamma Knife is a gamma knife specialized in the treatment of cranial diseases, as opposed to the current body or whole-body gamma knife. Gamma Knife was first invented by Professor Leksell, a famous Swedish neurosurgeon, who originally invented it in order to reduce the risk of high disability and mortality rate of traditional craniocerebral surgeries, and to realize the ideal of surgery without knife. The world’s first Gamma Knife was introduced in 1968 and installed at Sophiahammet Hospital in Stockholm, Sweden. After several upgrades (Figure 1-5, Figure 1-6), it is now a Perfexion type gamma knife. So far, the world production of cranial gamma knife countries only Sweden and China, in addition to Sweden’s Medical Technology Company, China’s Ovo, Masipu and Zunrui company respectively produce their own patented cranial gamma knife. In Leksell invented the gamma knife after up to 30 years of time, the gamma knife are specifically for the treatment of cranial diseases, until China’s Shenzhen Aovo company in 1998, the application of the principle of cranial gamma knife invented the whole body gamma knife, and then a number of domestic companies have invented a super gamma knife, the moon God Gamma Knife, gyroscope knife and other radiation therapy equipment for tumors, the gamma knife only to differentiate between the necessity of the gamma knife. This is because the Gamma Knife specifically used for the treatment of craniocerebral diseases and other Gamma Knife is a completely different model, the requirements and standards are not the same, with higher mechanical and radiophysical indicators. Cranial Gamma Knife is the most representative equipment for stereotactic radiosurgery, which is the “gold standard” of directional radiosurgery. It is the “gold standard” of directional radiosurgery. It is superior for the treatment of most cranial brain diseases such as cerebral arteriovenous malformation, cavernous hemangioma, benign intracranial tumors, metastatic tumors, and low-grade gliomas with the cranial Gamma Knife. The knowledge of Gamma Knife introduced in this book refers to the specialized Gamma Knife for cranial brain, i.e. Cranial Gamma Knife.