Radiation oncology is a separate discipline that brings together multidisciplinary and high-tech technologies. About 70% of tumor patients need to receive radiation therapy to varying degrees to cure tumors or relieve symptoms and improve quality of life. At present, the five-year cure rate of nasopharyngeal cancer, laryngeal cancer, rectal cancer and other early-stage or stage I tumors can reach more than 80-95% after simple radiation therapy, and the five-year survival rate of nasopharyngeal cancer, cervical cancer, Hodgkin’s lymphoma and prostate cancer at all stages can reach 40-50%. The combination of radiotherapy with surgery and chemotherapy can make 40% of all types of cancers strive for clinical cure. The remission rate of radiotherapy for intractable pain caused by bone metastasis of malignant tumors can reach 80-90%, and it can achieve the purpose of local control of tumors to different degrees. In recent years, with the recognition and clinical implementation of comprehensive tumor treatment theory and viewpoint, as well as the development and improvement of radiotherapy equipment and radiotherapy technology, especially the clinical application of conformal intensity modulated three-dimensional radiotherapy technology, the scope of radiotherapy indications has been expanded and the efficacy of tumor radiotherapy has been improved. The fact that radiotherapy has become one of the important and effective means to treat and control tumors is well recognized. Zhao Jing, Department of Oncology, Hebei Provincial People’s Hospital Radiation oncology, like all other disciplines, is still developing and improving, and will continue to make great contributions to safeguarding human health in a long period of time in the future. The goal pursued by radiation therapy for tumors is to be able to concentrate the radiation dose to the lesion (target area) to the maximum extent, kill the tumor cells, and at the same time protect the surrounding normal tissues and organs from unnecessary irradiation, which is the goal pursued by radiation therapy for tumors. The technical classification of radiotherapy: 1. conventional radiotherapy: The technical characteristics of conventional radiotherapy: 1. irregularly shaped irradiation field in two-dimensional direction obtained by regular shape or by lead mold masking. 2. The dose distribution of each point in the radiation field is relatively uniform. Advantages: the equipment and technical conditions are less demanding, the operation is relatively simple, and it is mostly used for radiotherapy before and after malignant tumor surgery. Disadvantages: the shape of the irradiation field does not exactly match the shape of the tumor in the three-dimensional direction, and there are more normal tissues in the irradiation field, which is not suitable for cases with sensitive tissues and vital organs around the tumor. Precision radiotherapy (taking intensity modulated conformal radiotherapy as an example) Features of precision radiotherapy: 1. What is conformal? In the three-dimensional direction, multiple fields and multiple angles are used for irradiation, and the cross-sectional shape of each field is consistent with the corresponding tumor cross-sectional shape. 2. 2. What is intensity modulation? The reverse 3D treatment planning system designs a reasonable and variable dose distribution based on the tumor condition using CT scans to achieve uniform dose at all points on the surface and inside the tumor. Advantages: It can increase the irradiation dose of tumor and kill tumor cells more effectively, and it can achieve the purpose of protecting normal tissues and organs more effectively, improving the efficacy and survival quality, and expanding the scope of indications for radiotherapy. Disadvantages: It is necessary to use spiral CT scan 3D imaging, analog positioning system and inverse 3D treatment planning system, which is more expensive and technically complicated, with strict repetition of body position and difficult operation.