Radiation therapy, referred to as radiotherapy, and chemotherapy, referred to as chemotherapy. Both radiotherapy and chemotherapy are the main methods of cancer treatment. The differences are: 1. Different treatment principles. Radiotherapy uses rays, such as x-rays and gamma rays, to kill tumor cells, while chemotherapy uses toxic chemicals to kill cancer cells. 2. Different durations. The tumor-killing effect of radiotherapy is immediate, that is, there is a killing effect during radiotherapy and the effect is discontinued when the treatment is stopped, while the tumor-killing effect of chemotherapy can last for several days in general. This is because the presence of chemicals in the human body generally lasts for several days. 3, the scope of action is different. Radiotherapy can only kill the cancer cells within the radiation range. Chemotherapy, on the other hand, as the chemicals enter the blood circulation and circulate throughout the body, theoretically speaking, as long as the blood can reach the area, it can generally play a tumor-killing role. 4. Treatment methods are different. Radiotherapy is a kind of physical therapy, which only needs to receive radiation for a few minutes every day and usually lasts from ten days to dozens of days, while chemotherapy requires oral or intravenous injection of drugs, and a cycle is 3-4 weeks.