In 1982, Betti and Derechinsky et al. began to explore the combination of stereotactic instrument and linear gas pedal to implement linear gas pedal isocentric rotational irradiation. In the same year, Colombo et al. proposed the theory and method of X-knife, and in 1987, Winston and Lutz et al. further improved the collimator, rotating frame and treatment bed of linear gas pedal, so as to make it compatible with stereotactic and rotational therapy, and established the method and standard of linear gas pedal isocenter test and calibration. In the early 1990s, X-knife gradually matured and rapidly spread its use around the world. China began to introduce X-knife in 1994, and later designed its own X-knife treatment system. X-knife is actually an improvement on the medical linear gas pedal used in conventional radiotherapy. In the original linear gas pedal with collimator, stereotactic device, adapter and treatment planning system and other auxiliary devices, through the linear gas pedal frame, the treatment bed were to do horizontal and vertical rotation (a number of non-coplanar arc dynamic focusing), so that the linear gas pedal through the X-rays emitted by the collimator to focus on the center of the three-dimensional localization of the disease coincides with the lesion, thus destroying the lesion tissue, while the normal tissues around the lesion only receive a small dose of radiation. Normal tissues are protected by a smaller dose of X-rays. Comprehensive head gamma knife and X-knife difference is mainly manifested in the following aspects: First, the source of radiation and rays are different: Gamma Knife is cobalt 60 as a radioactive source, radiating photon streams that is γ-rays. X-knife is a linear gas pedal through high-speed movement of charged particles to hit the target and radiated photon streams and characteristics of the radiation collectively referred to as X-rays. Although all are electromagnetic radiation, but γ-rays and X-rays are fundamentally different, the quality and energy are different, the controllability of the ray and the biological effects are not the same, the efficacy is not the same. Secondly, the localization method of the lesion is not the same: the head gamma knife stereotactic positioning framework is bone fixed, with four small screws directly fixed in the skull, firm and error-free. x-knife in addition to the one-time treatment with the gamma knife similar to the bone fixation, most of the time need to be irradiated, and thus more than the use of the head and face mold fixation. When bone fixation is used for positioning and single irradiation, X-knife belongs to the category of SRS; when head and face mold fixation is used for positioning and subdivided irradiation, X-knife belongs to the category of SRT. Thirdly, the precision of treatment is different: due to the X-knife in the treatment process, the gas pedal frame, the treatment bed to rotate and pull the arc movement, so the center of the X-rays may occur 0.6mm deviation. The source of head gamma knife is quite fixed, the distance from the source to the focus point is short, and the focus point has a fixed position, so the mechanical error of head gamma knife is less than 0.3mm, which is more accurate than X-knife, and more suitable for the treatment of small foci in the brain and the destruction of some nuclei in the brain. Fourthly, the degree of simplicity of operation is different: X-knife is more complicated and cumbersome to operate, and it needs to test and calibrate the accelerator-related parts and devices frequently, especially before each treatment, MIS must be used for isocenter verification, and only when it is confirmed that the error is not more than plus or minus 0.5mm can the treatment be carried out. Together with some other problems, this is probably the reason why X-knife is not used much nowadays and has been gradually marginalized. The operation of Gamma Knife is simpler and quicker, more automated and programmed, and only needs to be tested once a year, and its accuracy does not need to be verified before each treatment to ensure the safety of the treatment.