Q: What diseases can radionuclides treat?
A: Radionuclides can release beta rays when decaying, and their range is only a few millimeters, and almost all of them are absorbed by the diseased tissues, which can effectively destroy the diseased tissues and achieve the treatment purpose without any obvious effect on other tissues and organs.
Radionuclide therapy was first developed and most widely used for thyroid diseases, such as hyperthyroidism (hyperthyroidism), thyroid cancer and its metastases. Other treatments carried out include bone metastases from cancer, rheumatoid arthritis, ankylosing arthritis, and pheochromocytoma.
Q: What are the advantages of radionuclide 131 iodine treatment for hyperthyroidism (hyperthyroidism) and under what circumstances is radionuclide 131 iodine treatment suitable?
A: Radionuclide 131 iodine treatment for hyperthyroidism is one of the earliest methods used in nuclear medicine and has been used for nearly 70 years. 131 iodine is taken up by the thyroid gland and the beta rays emitted during decay have a very short range (about 2-3 mm) and are basically completely absorbed by the thyroid tissue. This method is easy, safe, economical, and effective, with a low recurrence rate and few complications, making it an ideal treatment for hyperthyroidism.
Patients with hyperthyroidism in Graves’ disease (toxic diffuse goiter) may be considered for radionuclide 131 iodine treatment in the following cases: abnormal liver function, leukopenia unsuitable for continued antithyroid drug treatment; allergy to antithyroid drugs; relapse after antithyroid drug treatment; relapse after surgical treatment or unwillingness to operate or contraindication to surgery; toxic nodular goiter with hyperthyroidism ( Plummer’s disease) and chronic lymphocytic thyroiditis combined with Graves’ disease may also be treated with radionuclide 131 iodine. Patients who are pregnant or breastfeeding, or who have hyperthyroidism combined with acute myocardial infarction or severe liver or kidney disease are not suitable for radionuclide 131 iodine therapy.
Q: What are the treatment options for hyperthyroidism in Graves’ disease? What are the advantages and disadvantages of each?
A: There are three main treatments for hyperthyroidism in Graves’ disease, including antithyroid medication, radionuclide 131 iodine treatment in nuclear medicine, and surgical treatment.
1. Anti-thyroid medication is relatively mild, and the dosage can be adjusted in time during the treatment. The disadvantage is that the course of treatment is long, usually requiring about 2.5 years of standardized treatment; during the treatment period, it may cause damage to liver function and hematopoietic system; when stopping or reducing the dosage, hyperthyroidism is prone to recurrence, and the recurrence rate is about 40%.
2.Radionuclide 131 iodine treatment is easy. Usually only one dose of radionuclide 131 iodine is taken, and the symptoms of hyperthyroidism start to be relieved about 4 weeks after treatment, and the cure rate of hyperthyroidism can reach 75~80% in about one year. Some patients whose hyperthyroidism symptoms do not improve significantly after six months of treatment can be treated with radionuclide 131 iodine again. Disadvantages: It is a destructive treatment for the thyroid gland, and hypothyroidism may occur after treatment, requiring lifelong application of thyroid hormone replacement therapy; it may aggravate Graves’ ophthalmopathy.
Surgery is usually used to treat hyperthyroidism by subtotal thyroidectomy, which relieves hyperthyroidism rapidly and is especially suitable for patients with obvious enlargement of the thyroid gland or with nodules. In some cases, it may cause complications such as damage to the laryngeal nerve and hypoparathyroidism. Some patients may still experience recurrence of hyperthyroidism or hypothyroidism after surgery.
Q: What preparations should be made before radionuclide 131 iodine treatment for hyperthyroidism?
A: Since iodine-containing foods, medications and anti-thyroid medications can affect the uptake of 131 iodine by the thyroid gland, anti-thyroid medications should generally be stopped for 1 to 2 weeks before treatment, and iodine, iodine-containing foods and medications should be stopped for about 2 to 4 weeks. During the discontinuation period patients with hyperthyroidism symptoms such as rapid heart rate and comorbidities such as low white blood cells and abnormal liver function should continue symptomatic treatment.
Q: What tests should be done before radionuclide 131 iodine treatment for hyperthyroidism?
A: Before the treatment of hyperthyroidism with radionuclide 131 iodine, patients should undergo routine tests such as thyroid function, blood and urine routine, biochemical indexes and electrocardiogram, etc. Ultrasound of the thyroid gland, thyroid nuclide imaging and iodine uptake rate measurement of the thyroid gland are used to determine the size of the thyroid gland and estimate the drug dose.
Q: Can a patient with hyperthyroidism with proptosis recover after radionuclide 131 iodine treatment?
A: According to different reports, 15-50% of hyperthyroid patients may have unilateral or bilateral proptosis. Some proptosis may appear before the onset of hyperthyroidism, some may appear during the treatment of hyperthyroidism, and a few patients may appear after the control of hyperthyroidism or even during hypothyroidism. The treatment of hyperthyroidism proptosis lacks special methods at home and abroad. Clinical practice shows that after radionuclide 131 iodine treatment, some patients’ proptosis is reduced; some patients’ proptosis is maintained; very few patients’ proptosis is aggravated even after their hyperthyroidism is controlled, and they should go to ophthalmology department for further symptomatic treatment.
Q: Does radionuclide 131 iodine treatment cause hypothyroidism (hypothyroidism)? How should hypothyroidism be treated?
A: A major complication of radionuclide 131 iodine treatment is hypothyroidism (hypothyroidism). Hypothyroidism can occur regardless of the method of treatment for hyperthyroidism, and is not unique to radionuclide 131 iodine therapy. Clinical manifestations of hypothyroidism include fear of cold, dry skin, swelling, joint inflexibility, muscle aches, drowsiness, and mental fatigue. Hypothyroidism is easy to diagnose and treat. Studies have shown that hypothyroidism that occurs within one year after radionuclide 131 iodine treatment (early onset hypothyroidism) can partially return to normal with thyroid hormone replacement therapy; however, hypothyroidism that occurs after one year (late onset hypothyroidism) often requires long-term or lifelong thyroid hormone replacement therapy. As thyroid hormone replacement therapy only replenishes the insufficient thyroid hormones in the patient’s body, it will not cause any dysfunction of tissues and organs and will not affect pregnancy or breastfeeding as long as the level of thyroid hormones in the body is adjusted to the normal range.
Q: What should I pay attention to after radionuclide 131 iodine treatment? In order to obtain better results after radionuclide 131 iodine treatment, patients must pay attention to the following aspects.
Food should be taken only after 2 hours of taking 131 iodine on an empty stomach to avoid affecting the absorption of 131 iodine.
Iodine, bromine and anti-thyroid drugs should not be used during the period before clinical symptoms start to improve, as this may affect the reabsorption of 131 iodine and reduce the efficacy of the treatment. A low iodine diet for 1 to 3 months after treatment and no sea plants such as seaweed and nori.
Patients should preferably rest in bed for one week after taking 131 iodine, avoid strenuous activities and mental stimulation, and prevent infection. Avoid squeezing the thyroid gland.
Some patients may experience digestive symptoms such as anorexia, nausea, vomiting, etc. A few have itchy skin, dizziness, and weakness, which can disappear in 2 to 3 days with symptomatic treatment.
After treatment, follow the doctor’s instructions for regular outpatient review and continue treatment of related comorbidities. No smoking and avoid smoking environment.
It is recommended to consider fertility plan more than 6 months after treatment.