Radiotherapy, or “radiotherapy” for short, is one of the main means of cancer treatment and has a wide range of application. The indications for radiotherapy include: 1. Tumors suitable for radiotherapy alone include early to mid-stage nasopharyngeal cancer, early to mid-stage sinus cancer, early tongue cancer, early laryngeal cancer, cervical and mid-stage esophageal cancer, early cervical cancer, early Hodgkin’s disease and early prostate cancer, etc. 2. 2.Tumors suitable for radiotherapy combined with surgery include early and mid-stage intracranial tumors, middle and late stage head and neck tumors, early thyroid cancer, lower esophageal cancer, early and mid-stage gastric cancer, early and mid-stage lung cancer, malignant thymoma, mid-stage cervical cancer, early and mid-stage rectal cancer, early and mid-stage anal canal cancer, seminomatous cell tumors and some soft tissue tumors. 3.Tumors suitable for radiotherapy combined with chemotherapy include small cell lung cancer of all stages, middle and late stage Hodgkin’s disease, malignant lymphoma of all stages and most of late stage malignant tumors. 4.Some adenocarcinomas and malignant mixed tumors cannot be treated with radiotherapy, such as breast cancer, thyroid cancer, gastric cancer, colon cancer, rectal cancer, liver cancer and parotid mixed tumors, etc. Most of them are treated mainly by surgery, and sometimes they can be combined with radiotherapy before or after surgery.