Taking radioactive 131 iodine for the treatment of hyperthyroidism is easy to use, has a high one-time cure rate and is low-cost, which is popular among patients. However, some people are worried that the radiation is harmful, will hurt people’s vitality, and will cause infertility. What are the facts? We should have a correct understanding of it. Hyperthyroidism (hyperthyroidism for short) is a very common endocrine disease with many causes and types, but the common feature is the secretion of too much thyroid hormone. Common self-conscious symptoms of hyperthyroidism include panic, rapid heartbeat, fear of heat, excessive sweating, short temper, fatigue, loss of weight, hyperphagia, increased bowel movements, etc. Some patients may also find that they are suffering from hyperthyroidism. Some patients may also notice a thickening of the neck and protruding eyes. If the above signs and symptoms occur, you should go to the hospital in time to do the relevant examinations. Patients suffering from hyperthyroidism do not need to panic, this disease is completely curable. However, it is different from cold and flu which will be cured in a few days, there is a process. At present, there are three common treatment methods: internal medicine anti-hyperthyroidism drug treatment; surgical treatment; radioactive iodine 131 treatment. Internal medicine refers to the use of anti-thyroid drugs, such as Tabazole, hyperthyroidism, methylthiouracil, propylthiouracil, etc., to inhibit the synthesis of thyroid hormones, the efficacy of which is certain and the method is simple. Its disadvantage is the long course of treatment, at least one and a half years of regular medication, and after stopping the drug recurrence rate is high, up to more than 50%. Surgery is the most effective treatment for toxic thyroid adenomas. If the adenoma is removed cleanly, there is usually no recurrence of hyperthyroidism in the future. The disadvantage is that it is a surgical procedure after all, which carries certain risks and has a high recurrence rate (30%). The use of radioactive 131 iodine to treat hyperthyroidism is currently recognized as an effective method in the world. Former U.S. President George W. Bush suffered from hyperthyroidism during his administration, after many world-class authoritative medical experts to consult and discuss, and finally determined to use this method of treatment, received good results. At present, this has been included in the preferred method in some western countries. Why isotope therapy has such obvious efficacy? Because the thyroid gland synthesizes thyroid hormones, iodine is the necessary raw material, radioactive 131 iodine and stable iodine have the same physiological and biochemical characteristics, the thyroid tissue also has a high degree of absorption and concentration ability. A large number of concentrated radioactive 131 iodine makes the thyroid gland subject to radiation, part of the thyroid tissue is destroyed, so that the production of thyroid hormones is reduced, hyperthyroidism is alleviated or cured. 131 iodine is an unstable radionuclide, in the process of decay can be emitted γ and β rays, and β rays account for 99% of the therapeutic role. Because of the short range of β-rays, the average 1 mm, the longest 2.2 mm, and thus the impact on the surrounding tissues and organs of the thyroid gland is very small or basically no effect. This shows that radioactive 131 iodine treatment of hyperthyroidism is a safe and simple method. Who is suitable for radioactive iodine treatment for hyperthyroidism? It is generally recognized that it is suitable for both male and female adult patients. There is a debate about the treatment of women of childbearing age and children. At the beginning of the use of 131 iodine in the treatment of hyperthyroidism, there were concerns about the risk of carcinogenicity, leukemia, and congenital anomalies in the fetus. After half a century of clinical practice, these concerns have been eliminated. Statistics of more than 1 million patients at home and abroad have not found any increase in the incidence of leukemia and thyroid malignancy, fetal malformations do not exceed the natural incidence, and there is no effect on fertility and development of offspring. It is now unanimously recognized by experts that treatment with 131 iodine is contraindicated in patients with hyperthyroidism during pregnancy and breastfeeding, because it can cause hypothyroidism in the fetus or infant. Therefore, we believe that 131 iodine is a safe treatment for patients of all ages (including women of childbearing age and children), except for pregnant and lactating women. Treatment of hyperthyroidism with radioactive 131 iodine is performed in the Department of Nuclear Medicine, and most patients are controlled after treatment and can be cured with a single dose. A few patients require a second treatment. It takes more than 3 weeks after taking 131 iodine for the treatment effect to begin to appear, and within 3 months the symptoms gradually improve, the thyroid gland shrinks, and the protruding eyes of some patients can also be reduced. 6 months to 2 years the symptoms are completely eliminated. If a second treatment is needed, it should be carried out after half a year, preferably 8 to 10 months apart. Some patients with hyperthyroidism have protruding eyes, the cause of which is more complicated and may be related to certain immune disorders in the body and other factors. Some people have also found that there is a substance in the patient’s serum that is related to the occurrence of protruding eyes. The combined effect of various factors makes the post-eyeball tissue increase and accumulation, muscle fiber tissue edema, lymphocyte infiltration, etc. 131 iodine treatment only a few cases may make the protruding eyeballs aggravated, and this should be correctly recognized. Hyperthyroid patients generally have no adverse reactions after taking 131 iodine, only a few patients have early reactions within 2 weeks after taking the drug, mainly nausea, vomiting, dizziness, fatigue; a few other patients have skin rashes and itching, which are generally mild and can disappear on their own. Late complications are mainly hypothyroidism, which is caused by insufficient synthesis and secretion or physiological effect of thyroid hormone. 131 iodine treatment caused by transient hypothyroidism, the symptoms are mild, and it can disappear by itself after 6~9 months. The other is permanent hypothyroidism, China reported that the incidence rate is 2%~5% in the first year, and with the extension of time, the incidence rate increases by 2%~3% year by year. However, hypothyroidism is not terrible, as long as the right amount of thyroxine is supplemented, normal thyroid function can be maintained. Some scholars believe that hypothyroidism is the natural history of hyperthyroidism, which can occur after various treatments and is not unique to 131 iodine treatment. To summarize, several methods of treating hyperthyroidism have their own characteristics, relatively speaking, radioactive 131 iodine treatment of hyperthyroidism has a wide range of indications, simple methods, safe and effective, less frequent medication, and a high cure rate.