Radioactive iodine 131I emits not only b-rays but also g-rays. g-rays are highly penetrating and can cause radiation hazards to the patient himself, the patients in the same ward, as well as to the surrounding health care workers and other normal people. Therefore, shielding isolation is required when high-dose radioactive iodine 131I treatment is performed. In addition, there is a large amount of radioactive excretion in the early days (within 5 days) of the patient’s treatment with radioactive iodine 131I, and this excretion requires a special sewage treatment system, otherwise it will seriously pollute the environment. Therefore, the entire early phase of radioactive iodine 131I treatment needs to be carried out under radiation isolation conditions. In addition, patients may develop various complications while receiving high-dose 131I treatment, and hospitalization can be detected and treated early to reduce the occurrence of accidents. For more information about the requirements and precautions for isolation treatment in nuclear medicine wards, please refer to the bulletin board in the ward or consult our physician on duty at our nuclear medicine specialty clinic.