Radiotherapy is categorized into internal radiation therapy and external radiation therapy. In principle, there is no need to isolate children after external radiation therapy, while internal radiation therapy requires isolation from children. External radiation therapy patients themselves do not carry radioactive particles, generally speaking, as long as the environment is removed from the radiation therapy, the patients themselves are radiation-free, and can be in contact with children and other special populations. However, internal radiation therapy is to implant radioactive particles into the patient’s body, and there is a radioactive source in the patient’s body, which cannot come into contact with children and should be isolated from children so as not to affect children’s growth and development. If patients undergo radiation therapy, they should ask the doctor in detail about the precautions for radiation therapy, follow the doctor’s instructions, and stay away from pregnant women, children and other special groups.