1. Radiotherapy: Radiotherapy, commonly known as “baking electricity” and “shining light”, is a method of treating tumors with radiation, which usually adopts X (γ) lines, electron lines or proton rays to kill and damage cancer cells. Radiotherapy is one of the most prominent treatments for malignant tumors, with more than half of all tumor patients requiring radiotherapy. Tens of thousands of patients with tumors have been cured after receiving radiotherapy alone or comprehensive treatment that includes radiotherapy. 2.Localization: The process of using special X-ray imaging techniques to precisely identify and mark the treatment target area in the design of the radiation treatment plan. In order to ensure the accuracy of treatment, “mask”, “body membrane” and other body fixation techniques are often used in the positioning process. Radiotherapy field: The area of the body to which the radiation is directed and through which the radiation passes, also known as the “field of fire”. 4, radiotherapy plan design: refers to determine the treatment target area, select the appropriate ray and design a reasonable irradiation field, determine the dose of radiotherapy and a series of processes, the purpose is to ensure that the radiation can maximize the killing of tumors, while minimizing the impact on the body’s normal tissues. 5, conventional simulator: X-ray machine and equipment used for radiotherapy positioning. The reason why it is called “simulation machine” is because its appearance and radiotherapy machines like, can simulate different angles of the irradiation field, but can not implement the treatment. X-ray images generated by the simulator to locate and mark the radiotherapy target area. 6, CT simulation positioning: through the CT scanning and image of the three-dimensional reconstruction technology to obtain the patient’s image data, can be in three-dimensional space to show the scope of the tumor and its surrounding normal tissues, so as to replace the conventional simulation machine. CT simulation positioning is an important premise and basis for the design of three-dimensional shape-adapted radiotherapy and intensity-modulated radiotherapy and other precise radiotherapy plan. 7, accelerator: also called linear gas pedal, can produce high-energy rays for tumor treatment. Gas pedal is the most commonly used therapeutic equipment for radiotherapy. Radiotherapy sensitivity: the degree of difficulty for tumor cells or normal cells to be affected by radiation. Cells that proliferate and divide quickly are easily damaged by radiation and have high radiosensitivity. 9.Conventional fractionated radiotherapy: It refers to the conventional radiotherapy with a dose of 1.5-2.0Gy/times, 5 times/week, which is applicable to the radiotherapy of most malignant tumors. Unconventional fractionated radiotherapy: including super-fractionated radiotherapy (increase the number of radiotherapy, reduce the dose of each radiotherapy, the total course of treatment remains unchanged, the purpose is to further reduce the response of late radiotherapy in the case of the same early radiotherapy response or mild increase, and the control of the tumor is the same as or better than that of conventional fractionated radiotherapy), accelerated fractionated radiotherapy (increase the dose of radiotherapy each time or every day, the total course of treatment is shortened, the aim is to reduce the risk of proliferation of the tumor during the treatment process to the treatment. Accelerated fractionated radiotherapy (increasing the dose per treatment or per day and shortening the total course of treatment in order to reduce the effect of tumor proliferation during treatment), accelerated hyperfractionated radiotherapy (increasing the number of radiotherapy sessions, decreasing the dose per session, and shortening the total course of treatment in order to reduce the response of advanced radiotherapy, and at the same time, reducing the effect of tumor proliferation during treatment on the efficacy of the treatment).