Overview of Radiation Oncology Radiation oncology is an independent discipline that combines multidisciplinary and high-tech technologies. About 70% of tumor patients need to receive radiation therapy to varying degrees in order to cure the tumor or relieve symptoms and improve the 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. Like all other disciplines, radiation oncology is still developing and improving, and will continue to make great contributions to the defense of human health in a long period of time in the future. What are the advantages of radiation therapy? Radiation therapy is one of the three major clinical treatments for tumors (surgery, radiotherapy and chemotherapy). Its advantages are as follows: 1. It has a wide range of application and can treat almost any tumor in all parts of the body. Patients who cannot tolerate other therapies because of their age, poor physical condition or multiple surgeries can receive radiation therapy. 3.The effect of treatment is reliable and the treatment method is reliable. 4.The treatment process is simple, painless, does not necessarily require hospitalization, and is easily accepted by patients. It can avoid anesthesia accident caused by surgery, blood transfusion reaction, postoperative infection, and side effects such as hair loss and vomiting caused by chemotherapy. 6.Radiation therapy is non-invasive and can preserve the physiological function of diseased organs. The goal of radiation therapy for tumors is to maximize the radiation dose to the lesion (target area) and kill the tumor cells, while protecting the surrounding normal tissues and organs from unnecessary irradiation. The technical classification of radiotherapy: 1. Conventional radiotherapy: The technical characteristics of conventional radiotherapy: 1. 2, the dose distribution of each point in the irradiation 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 included in the irradiation field, which is not suitable for cases with sensitive tissues and vital organs around the tumor. Precise radiotherapy (taking intensity modulated conformal radiotherapy as an example) Features of precise radiotherapy: 1. 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. What is intensity modulation? According to the tumor condition, using CT scan, the inverse 3D treatment planning system designs a reasonable and variable dose distribution to make the tumor surface and internal points receive uniform dose. 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 radiotherapy indications. Disadvantages: It is necessary to use spiral CT scan 3D imaging, analog positioning system and reverse 3D treatment planning system, which is more expensive and technically complicated.