Nuclear medicine in the treatment of thyroid disease
What is hyperthyroidism?
Hyperthyroidism is a clinical syndrome caused by an increase in thyroid function and an overproduction of thyroid hormones due to various causes. The main manifestations of hyperthyroidism include panic attacks, fear of heat, excessive sweating, hyperphagia, weight loss, increased frequency of stools, fatigue, agitation, and enlargement of the thyroid gland. The most common type is diffuse goiter with hyperfunction. This is followed by autonomic hyperfunctional thyroid adenoma and multinodular goiter with hyperthyroidism. Lv Zhongwei, Department of Nuclear Medicine, Shanghai Tenth People’s Hospital Xie Wenjie, Department of Hematology and Oncology, Penglai Chinese Hospital
Why does the human body get hyperthyroidism?
At present, the cause and pathogenesis of hyperthyroidism have not yet been fully elucidated. Modern medical research proves that the disease is triggered by stress factors such as infection, mental stimulation and trauma on a genetic basis, and is an autoimmune disease.
Who is prone to hyperthyroidism?
Hyperthyroidism is more common in women, younger people and people with a family history of hyperthyroidism. Clinical statistics show that there are significantly more women than men with hyperthyroidism, and the ratio of male to female patients is about 1:4-6. Although the disease can develop in all age groups, it is more common in younger people (20-40 years old), followed by older people, and less common in children. The incidence of hyperthyroidism in the family is significantly higher than that in the general population.
What are the clinical manifestations of hyperthyroidism and what are the risks?
The typical clinical manifestations of hyperthyroidism are fear of heat, excessive sweating, hyperphagia, easy hunger, emaciation, fatigue, panic and shortness of breath, emotional instability, irritability, poor sleep, protruding eyes, enlarged thyroid gland, increased stools or diarrhea, muscle weakness, periodic paralysis, osteoporosis, decreased menstruation or amenorrhea in females, and a lack of blood pressure. decreased menstruation or amenorrhea in women, and impotence in men. Therefore, hyperthyroidism is not a localized disease, but a systemic disease that affects all organs and systems. If left untreated or not treated properly, it will seriously endanger the health of patients.
Can a woman with hyperthyroidism get pregnant? Does it have any effect on the fetus?
Both thioureas (methyl and propylthiouracil) and radioactive iodine can enter the fetus through the placenta, which can cause fetal brain failure and fetal goiter at high doses and may cause obstructed labor. At the same time, hyperthyroidism pregnancy can aggravate the disease and even cause serious complications, which is extremely unfavorable to the pregnant woman herself. Therefore, women with hyperthyroidism should not rush to get pregnant, but should actively treat their hyperthyroidism and wait until they are cured before they can get pregnant.
What should I do if I have hyperthyroidism?
Generally speaking, if a patient has fear of heat and sweating, excessive food and weight loss, excitement and irritability, trembling of the hands and feet, and continuous or frequent tachycardia, she should consider that she may have hyperthyroidism and should go to a regular hospital as soon as possible. Once the diagnosis is confirmed, treatment should be carried out according to the doctor’s advice. Don’t delay the treatment because of light symptoms, and don’t go to irregular private clinics or small hospitals to save money, resulting in missed diagnosis, misdiagnosis or mistreatment.
What are the advantages and disadvantages of internal treatment (oral anti-thyroid drugs) for hyperthyroidism?
Advantages: wide range of application, from infants to the elderly and pregnant women; effective in most cases; flexible in medication and can be adjusted according to the patient’s condition; relatively inexpensive and easy to accept.
Disadvantages: high relapse rate after stopping medication, up to 50%; some patients have difficulty tolerating side effects of medication; for patients with complications of hyperthyroidism, such as hyperthyroid heart disease, hyperthyroidism with periodic paralysis, and diffuse goiter eye disease, medication is less effective.
Can hyperthyroidism be treated surgically?
Yes. However, with the exception of patients with obvious goiter or clinically suspected thyroid tumors, surgery for hyperthyroidism is no longer necessary because isotope 131 iodine therapy and surgery are both curative treatments for hyperthyroidism, and the latter is considered a non-invasive surgical treatment.
Why can radioactive 131 iodine treat hyperthyroidism?
The thyroid gland uses iodine as the main raw material to synthesize thyroid hormone, so it is highly iodophilic, i.e. once iodine from food, water or medicine enters the body through the digestive tract, it is quickly absorbed by the thyroid gland, so 80% of the total iodine in the body is concentrated in the thyroid gland. Radioactive iodine is also an element of iodine. When taken orally, it can be concentrated in the thyroid gland as quickly as ordinary iodine, and the b-rays released by it can gradually destroy the hyperplastic thyroid tissue, causing the patient’s thyroid gland to shrink unknowingly and reducing the production of thyroid hormones, thus reducing or curing hyperthyroidism. This is a biological missile type of treatment. Surgery involves removing a portion of the thyroid gland with a scalpel to achieve treatment, while radioactive iodine uses b-rays to destroy a portion of the thyroid gland to achieve treatment. These two treatments can be considered similar. However, surgical treatment is bloody, painful and dangerous, while radioactive iodine treatment is bloodless, safe and painless. It is no wonder that some patients call it a “no-incision, no-bleed, no-pain surgery”.
Why is radioactive 131 iodine an excellent and new treatment for hyperthyroidism?
The treatment is particularly easy, economical, safe and painless. Most patients are treated on an outpatient basis and do not need to be hospitalized. After taking the medication for 2 to 3 weeks, the symptoms begin to decrease and are gradually cured, without the pain of surgery and avoiding the disadvantages of other medications that require long-term medication and are difficult to cure. It can be said that this one-time treatment method is the easiest and most economical treatment method for hyperthyroidism at present. Even if a few patients have reactions, they can be avoided or minimized if appropriate measures are taken before and during the treatment. Even if a few patients have reactions, they can be avoided or reduced to a minimum if appropriate measures are taken before and during treatment.
The treatment effect is particularly good. The effectiveness rate is more than 98%, and the cure rate (i.e. the cure rate of taking one dose or one sip of medicine) is as high as 70-80%.
It can treat patients with serious complications, such as heart disease, recurrence after surgery, or difficulty in re-operation after surgery.
There is no damage to the parathyroid glands, the recurrent laryngeal nerve and other peri-thyroid tissues, and thus no complications that may arise from surgical treatment, such as twitching of the hands and feet, hoarseness and inability to speak. There is no scarring of the neck, and it does not affect the aesthetics.
In the few cases where radioactive iodine has not healed once, the treatment can be repeated, and it does not affect the switch to other methods of treatment in the future.
No significant toxic side effects.
Because of the unique advantages of radioactive iodine treatment that cannot be replaced by other methods, it is currently considered the first choice for adult hyperthyroidism, except for patients who are not suitable for this treatment during lactation and pregnancy.
Why is 131 iodine treatment for hyperthyroidism safe?
Radioactive iodine treatment for hyperthyroidism has no significant effect on the bone marrow and therefore does not cause a decrease in white blood cells; nor does it cause hair loss, affect fertility, cause secondary leukemia, cause malformations or genetic abnormalities, or cause cancer. This is the scientific conclusion of long-term research on radioactive iodine treatment of hyperthyroidism by scholars at home and abroad over the past decades. Some bizarre rumors in the society and deliberate exaggerations in some literary works are unfounded and not credible. Although a small number of patients may have hypothyroidism (hypothyroidism for short), it will be corrected rapidly with thyroid hormone replacement therapy.
What are the contraindications of 131 iodine treatment for hyperthyroidism?
Pregnant and lactating patients;
Patients with significant enlargement of the thyroid gland with symptoms of pressure;
Patients with hyperthyroidism with recent myocardial infarction;
Patients with severe hepatic or renal insufficiency.
What are the indications for 131 iodine treatment of hyperthyroidism?
Patients with hyperthyroidism other than those contraindicated above.
What other diseases can be treated by nuclear medicine?
Thyroid cancer: Modern medicine believes that the formal treatment of thyroid cancer consists of three parts, one of which is indispensable. One is surgical removal of the primary lesion and the metastatic lesions that may be removed; the second is destruction of the residual thyroid tissue and occult metastatic lesions after surgery with radioactive 131 iodine; and the third is lifelong thyroid hormone replacement therapy to correct hypothyroidism and inhibit the recurrence and growth of the tumor.
Bone metastasis cancer: bone metastasis may occur in almost all malignant tumors, and autopsy confirms its incidence to be 50%, among which the bone metastasis rate of prostate cancer, breast cancer and lung cancer can be as high as 85%, which seriously affects the quality of life of patients. Radionuclide treatment for bone metastases has the following advantages: easy treatment, good pain relief, elimination and reduction of bone metastases, and no serious bone marrow suppression. Currently, 153Sm-EDTMP (153Sm-EDTMP) and 89SrCl2 (89 strontium dichloride) are well established and effective radiopharmaceuticals.
Malignant pheochromocytoma, neuroblastoma and extra-adrenal malignant paraganglioma and its metastases, carcinoid tumor, medullary thyroid carcinoma: 131I-MIBG (131 iodine-m-iodobenzylguanidine) is a neuronal blocking agent that can be taken up by such tumors with neurosecretory granules. 131I-MIBG releases b-rays that cause tumor cells to be inhibited and destroyed by larger radiation, thus achieving therapeutic purpose.
Certain blood diseases: After 32P (32 phosphorus) enters the body, the diseased tissues are very sensitive to the b-rays released by it, and the activity of the abnormally proliferating cells in the bone marrow can be blocked and inhibited, thus achieving therapeutic purposes. In clinical practice, 32P is most effective in true erythrocytosis and primary thrombocytosis.
Radionuclide colloid therapy: Radionuclides are injected directly into the body cavity or organ cavity to irradiate local tumor cells in order to control tumor development. It is mainly applied to those with resected primary or metastatic lesions and still positive biochemical indexes, those with partially resected or unresected primary or metastatic lesions, cancerous thoracoabdominal fluid, recalcitrant or recurrent synovial fluid overflow due to arthritis or rheumatoid arthritis.
Radionuclide interstitial therapy (or intra-tissue therapy): Radionuclide is directly injected and infiltrated into tumor tissues. It is mainly applied to metastatic lymph nodes that cannot be treated by other methods and primary foci of cancer that have metastasized extensively and cannot be removed, such as ovarian cancer, lung cancer, prostate cancer and cervical cancer.
Radionuclide dressing therapy: using radionuclides emitting b-rays to irradiate certain superficial lesions externally, which only affects the lesioned tissues and does not cause damage to normal tissues, mainly applicable to simple cutaneous hemangioma, spongy cutaneous hemangioma, keloid, stubborn eczema, limited neurodermatitis, axillary odor, corneal cloud opacity, etc. The treatment is painless, easy to operate, convenient to treat and has remarkable therapeutic effect, which is easily accepted by patients, including infants and children.
Why must 131 iodine therapy be performed after thyroid cancer surgery?
Many metastatic lesions of thyroid cancer, especially distant metastases, such as lung and bone, are difficult to be removed by surgery;
In order to avoid damaging the parathyroid glands and the laryngeal nerve, it is impossible to remove all thyroid tissues during surgery, and there will always be residual thyroid tissues;
The residual thyroid tissue after surgery often makes the method of detecting recurrence and metastasis of thyroid cancer much less sensitive, which prevents early diagnosis and delays treatment.