Cranial gamma knife is through the stereotactic technology, the distribution of tens or even hundreds of cobalt 60 sources on the half of the spherical steel body radiated lower energy gamma rays (γ rays), from different positions and angles, through guidance, collimation, beam limiting, focus will be precisely converge to the predetermined target area in the skull, in the target area to form a huge energy dose field. The energy in the center of the focal point is the largest, and the dose decreases sharply in the surrounding area, and the gradient of the dose decrease is very large and fast, and the energy outside the focal point is very small, so that the focal point is like a sharp “knife”. And the size and shape of the focus can be changed and optimized through the computerized treatment plan design system, so that the size and shape of the effective dose field of the focus exactly matches the size and shape of the intracranial lesion, and the huge energy of the radiation focus destroys the tissue inside the lesion at one time, while the normal brain tissue outside the lesion is protected from damage because it is only exposed to a small amount or momentarily. Because the cranial gamma knife treatment has a surgical-like effect and almost no damage to normal brain tissue, the cranial gamma knife to achieve a one-time high dose of irradiation treatment, without the need for split treatment (unless special circumstances or special lesions intentionally), which is currently other stereotactic radiation therapy equipment does not have the advantage. From the radiobiological point of view, the gamma knife once treatment dose is equivalent to or even greater than the total radiation dose of a course of ordinary radiotherapy, even for benign intracranial tumors that are not sensitive to ordinary radiotherapy can also play a good therapeutic role.