Hyperthyroidism Radioactive iodine (131I) treatment for hyperthyroidism is the earliest and most widely used radionuclide treatment technique in clinical practice, with a history of more than 50 years. It is an ideal treatment for hyperthyroidism because it is simple, safe, economical and highly effective, and has a low recurrence rate and few complications. If the patient receives proper guidance in time and strictly carries out the medical prescriptions of the nuclear medicine specialist, the cure rate of radioactive iodine for single treatment of hyperthyroidism is generally over 75%, and the overall cure rate for repeated treatment is over 90%, only a few patients have poor results and need additional treatment. In some cases, transient or prolonged hypothyroidism may occur after treatment, which can be corrected by daily oral replacement therapy with appropriate amounts of thyroxine tablets. Metastatic bone pain from malignant tumors Many advanced malignant tumors will have bone metastases to varying degrees, among which the more common ones include breast cancer, prostate cancer, lung cancer, nasopharyngeal cancer, thyroid cancer and rectal colon cancer. Some tumors with bone metastases have obvious bone pain symptoms, and even develop into refractory bone pain, which is difficult to control even with external irradiation, chemotherapy and anesthetic analgesic drugs. If the clinical diagnosis is clear and the bone metastases have obvious osteogenic metabolic manifestations, in principle, radionuclide therapy (strontium 89Sr, trade name: Metatron; samarium 153Sm-EDTMP, trade name: samarium lysine) should be taken in time to relieve the pain and/or control the development of bone lesions, so as to effectively improve the survival and quality of life of patients. Neuroendocrine malignancies Some specific types of neuroendocrine malignancies (e.g., pheochromocytoma, neuroblastoma, medullary thyroid carcinoma, etc.) may be difficult to radically treat surgically, and the efficacy of chemotherapy and external radiotherapy for these tumors is often uncertain, making it difficult to control the progression of the disease with conventional treatment. These cancer lesions can ingest and collect radioactive 131I-MIBG. The beta radiation released by 131I exposes the tumor to a large amount of radiation, which inhibits and destroys the activity of the tumor, so that the symptoms can be reduced, the tumor can be shrunk or the further development of the cancer lesion can be controlled for treatment purposes. The efficiency of this treatment method is about 50%. If the treatment is effective but not cured, it can be repeated several times depending on the development of the disease, and the interval between treatments is usually 1 to 2 months. Differentiated thyroid cancer cells generally retain the ability of normal thyroid cells to take up and use iodine ions, so these cancer cells can also take up and collect the radioisotope iodine 131I, which releases radioactive particles (b-rays and g-rays), and these rays (especially b-rays) have a strong effect on killing cancer cells. Thyroid cancer cells are quickly killed by the radiation after ingesting and collecting radioactive 131I, just like “drinking their own poison”. Radioactive iodine 131I is the most effective and reliable method to treat residual lesions and/or metastases of thyroid cancer after surgery. The overall efficiency of treatment is nearly 90%, in which some patients (especially those who are young, with mild disease, small number of metastases and small lesions) can be cured, and in most cases the disease can be controlled and the quality of life improved. In very few cases, the treatment is ineffective.