1.Radiotherapy: radiation therapy, commonly known as “baking electricity” and “shining light”, is a method of treating tumors with radiation, usually using X (γ) rays, electron rays or proton rays to kill and damage cancer cells. Radiotherapy is one of the primary treatments for malignant tumors and is required for more than half of all tumor patients. Tens of thousands of tumor patients have been cured after receiving radiotherapy alone or a combination of treatments that include radiotherapy. 2.Localization: The process of precisely identifying and marking the treatment target area using special X-ray imaging technology in the design of radiation treatment plan. In order to ensure the accuracy of treatment, positioning techniques such as “face mask” and “body mask” are often used in the positioning process. 3.Radiotherapy field: the area in the body where the radiation is directed and passed through, also called “field”. 4.Radiotherapy plan design: It is the general term for a series of processes such as determining the treatment target area, selecting the appropriate radiation and designing a reasonable radiation field, and determining the dose of radiotherapy, etc. The purpose is to ensure that the radiation can kill the tumor to the maximum extent while minimizing the impact on the normal tissues of the body. 5.Conventional simulator: X-ray machine and equipment used for radiotherapy positioning. It is called “simulator” because its appearance is similar to radiotherapy machine and can simulate different angles of irradiation field, but cannot implement treatment. The X-ray image generated by the simulator is used to locate and mark the radiotherapy target area. 6.CT simulation and positioning: The CT scan and 3D reconstruction technology can be used to obtain the patient’s image data, which can display the tumor area and its surrounding normal tissues in 3D space, thus replacing the conventional simulator, and CT simulation and positioning is an important prerequisite and basis for the design of precise radiotherapy plans such as 3D conformal radiotherapy and intensity modulated radiotherapy. 7.Accelerator: It is also called linear gas pedal, which can produce high-energy rays for tumor treatment. Gas pedal is the most commonly used treatment equipment for radiation therapy. 8.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 split radiotherapy: It is the conventional radiotherapy with radiation dose of 1.5-2.0Gy/time and 5 times/week, which is applicable to the radiation therapy of most malignant tumors. 10.Unconventional fractionated radiotherapy: including super fractionated radiotherapy (increase the number of radiotherapy sessions, decrease the dose of each radiotherapy session, and keep the total course of treatment unchanged, the purpose is to further reduce the response to late radiotherapy while the tumor control is the same or better than conventional fractionated radiotherapy in the case of the same or mildly increased response to early radiotherapy), accelerated fractionated radiotherapy (increase the dose of each or daily radiotherapy sessions, and shorten the total course of treatment, the purpose is to reduce the impact of tumor proliferation on the treatment due to the tumor proliferation during the treatment process. The aim is to reduce the effect of tumor proliferation during treatment), accelerated hyperfractionated radiotherapy (increase the number of radiotherapy sessions, reduce the dose of each radiotherapy session, and shorten the total course of treatment, in order to reduce the response to advanced radiotherapy while reducing the effect of tumor proliferation during treatment).