A review after five years of iodine-131 treatment for thyroid cancer is recommended in nuclear medicine or endocrinology. Iodine-131 treatment for thyroid cancer is to take advantage of the fact that thyroid cells can ingest and use the mechanism of radioactive iodine to exterminate thyroid cancer, thus achieving the purpose of treating thyroid cancer. It is mainly applicable to differentiated thyroid cancer. Iodine-131 treatment is a kind of radiation therapy, which removes residual thyroid tissues and cancer cells and at the same time has certain radiation to other organs of the body, so it is necessary to regularly review the blood routine, liver and kidney functions and electrolytes, to observe the side effects, to adjust the dosage of thyroxine tablets as well as to evaluate the effect of iodine-131 treatment, so the review after five years should be done in the Endocrinology Department or the Department of Nuclear Medicine. In some patients, these tests and treatments are performed in the Department of General Surgery or the Department of Thyroid Surgery, which may also be the place to go for review. It is recommended that after thyroid iodine-131 treatment you need to follow the doctor’s instructions for regular review, and if there are any adverse reactions, they should be handled under the guidance of a medical professional.