Iodine 131 treatment is a type of radiotherapy. Iodine 131, also known as I131 in clinical practice, uses the radioactive isotope of iodine that can be ingested by thyroid cells and then releases ß and γ rays to destroy local thyroid tissues, and it is a type of radiotherapy because it utilizes the principle of radioactivity for treatment. Iodine 131 is mainly used in the treatment of adult Graves’ disease. Due to the radioactive nature of the treatment, it is contraindicated in pregnancy and lactation, and women are required to exclude pregnancy before treatment and avoid pregnancy for 6 months after treatment. Therefore, Iodine 131 treatment has a certain degree of radioactivity, it is recommended to consult with a doctor to understand the advantages and disadvantages of the treatment before treatment, and actively treat according to the doctor’s evaluation recommendations.