Soon after Roentgen’s discovery of X-rays in 1895, X-rays were used as the earliest form of treatment for malignant tumors, i.e. radiotherapy. Through X-ray therapy machines (10-60KV), superficial X-ray machines, deep X-ray machines, 60Co therapy machines, linear gas pedals, to today’s image guided radiotherapy systems (IGRT) (based on linear gas pedals) and so on. From two-dimensional radiotherapy (conventional radiotherapy), it has evolved to three-dimensional conformal (3D-CRT), intensity-modulated radiotherapy (IMRT), and four-dimensional intensity-modulated radiotherapy (including image-guided radiotherapy, IGRT; respiratory gated intensity-modulated radiotherapy; adaptive radiotherapy; bio-intensity-modulated radiotherapy, BRT, etc.). Gamma-knife, X-knife and gyroknife are all methods of radiation therapy Similar in principle, they are characterized by a single high-dose irradiation, which can play a rapid role in killing tumors. Radiotherapy for tumors can use the above methods, but it needs to be combined with irradiation of clinical target area (CTV). Some units ignore the irradiation of clinical target area (CTV) when they irradiate the whole tumor target area (GTV) with γ-knife, X-knife or gyroknife, and as a result, the tumor is easy to recur, which is not desirable. Most of the linear gas pedals can carry out X-knife radiotherapy technology, which can fully meet the needs of radiotherapy for tumors in all parts of the body.