The development of modern medicine has gradually made human control and conquest of cancer a reality. In the clinical treatment of tumors, surgery, radiotherapy and chemotherapy are the three main treatment methods, and radiotherapy is more selective due to its broad indications, so that more than 70% of malignant tumor patients can receive radiotherapy at some stage of their treatment. The purpose of radiotherapy is to maximize the radiation dose to the lesion area (target area) to kill the tumor cells, while the surrounding normal tissues or organs are less or free from unnecessary irradiation, and some important organs such as brainstem, crystal, spinal cord, kidney, gonads, etc. need special protection. Many people think that modern radiotherapy technology still stays at the level of traditional radiotherapy technology and it is impossible to do this, but in fact, it is not. The modern precision radiotherapy technology, which is brought about by the combination of advanced computer technology and the linear gas pedal, is moving towards this idealized goal. Precision radiotherapy is based on conventional radiotherapy and incorporates three-dimensional image processing technology, high-precision radiation dose calculation algorithm, sophisticated linear gas pedal series technology, advanced tumor diagnosis technology and other technological achievements, so it is also called stereotactic radiotherapy. It is based on the premise of effective body position fixation and precise tumor localization, to accurately gather rays on the tumor from multiple directions in three-dimensional space, forming a high-dose area that closely follows the tumor, so that the dose difference between tumor tissues and normal tissues is enlarged, and finally achieving the purpose of killing tumor cells and reducing radiation damage to surrounding normal tissues. Unlike traditional radiotherapy techniques, precise radiotherapy includes 3D conformal radiotherapy and intensity modulated conformal radiotherapy, which has the advantages of “four most”, i.e. the highest dose in the target area (lesion area), the smallest dose to the normal tissues around the target area, the most uniform dose distribution in the target area, and the most accurate target area positioning and irradiation, and has benefited numerous tumor patients. Don’t fall into the misunderstanding of radiotherapy sensitivity Director Ma pointed out that it is now necessary to re-understand the issue of radiation sensitivity of tumors. Modern radiotherapy will make the original moderately sensitive tumors become highly sensitive and insensitive tumors become moderately sensitive. If a total dose of 100Gy or more is allowed to be irradiated, or 70Gy or more is irradiated in a relatively short period of time (within 2-3 weeks), most tumors will be completely eliminated, at which time sensitivity and insensitivity are not important, and insensitive tumor cells are difficult to survive. Therefore, the sensitivity or insensitivity of tumor to radiation is only a reference factor for doctors to give the amount of radiation therapy dose, but not a key factor to decide whether radiation therapy can be given. In other words, even if the tumor is pathologically classified as insensitive, if the tumor is small and the location allows high dose and short course of irradiation, the tumor can be cured radically. On the contrary, when the tumor is too large and the normal tissues involved in irradiation are too extensive to allow too much dose, even if the tumor is sensitive, good treatment effect cannot be achieved. Therefore, whether a tumor is effective for radiation therapy should be judged by the location of the tumor, the size of the tumor, the dose tolerance of the surrounding normal tissues and other factors, and finally the total dose and time of irradiation allowed to determine the efficacy, and the traditional sensitivity or insensitivity of radiation therapy should never be used to determine whether radiation therapy is available. Some early-stage tumors can be cured radically A large number of clinical results have proved that stereotactic radiotherapy can be used for primary or secondary tumors in the head and neck, chest, abdomen, pelvis and extremities, as well as the treatment of residuals after surgery or the treatment of mass reduction before surgery. It can obtain the same radical effect as surgery in the treatment of early stage lung cancer and liver cancer, etc., and is free from the pain and risk of surgical procedures. In addition, it has shown unparalleled therapeutic advantages in some special cases. In a lung cancer patient, the tumor grows close to the spine, if irradiated with conventional techniques, the treatment is definitely palliative, also commonly known as “not curable”, because the radiation tolerance of the spinal cord is much lower than the radical dose of the tumor, and curing the tumor is definitely at the cost of “paralysis”. “If the spinal cord is avoided, the tumor will be palliated, which is irreconcilable. In this case, the intensity modulated conformal radiotherapy can play the role of both treating the tumor and protecting the spinal cord, which is of great significance. Therefore, many experts and scholars at home and abroad call intensity modulated conformal radiotherapy a revolution in the history of radiotherapy treatment, which is applicable to the radiotherapy of most tumors such as prostate cancer, lung cancer, head and neck tumors, mesothelioma, central nervous system tumors, etc. It can not only enable patients to obtain a better tumor cure rate, but also a higher quality of survival, and is the mainstream of tumor radiotherapy in the 21st century.