Radioactive Iodine Therapy for Thyroid Disease
Thyroid hormones are essential for the human body. They regulate metabolic processes, the functioning of the gastrointestinal tract and cardiovascular system, and a person's mental state. Excess thyroid hormones (hyperthyroidism) or deficiency (hypothyroidism) can lead to serious disruptions in the body’s functioning.
Hyperthyroidism is a relatively common condition. The most common causes of this condition are the autonomous functioning of the thyroid nodules or immune-mediated hyperthyroidism, also known as Graves' disease or diffuse toxic goiter.
Drug therapy can only alleviate the symptoms of this condition; it cannot permanently eliminate the underlying cause. The desired outcome can be achieved through treatment with radioiodine therapy or surgical removal of thyroid tissue.
Both methods are equally effective, but radioactive iodine therapy carries fewer risks than surgery.
Radioactive iodine specifically targets only the overactive thyroid cells that need to be destroyed. At the same time, the recurrent laryngeal nerves and parathyroid glands remain unharmed. There is also no risk of postoperative bleeding. In each individual case, the doctor works with the patient to select the appropriate treatment method.
Radioiodine therapy in Germany: facts and figures
Radioiodine therapy was first performed in the United States in 1942. The first treatment with radioactive iodine in Europe took place in 1949 at Bonn University Hospital. Professor Winkler, the future director of the Center for Nuclear Medicine at the University Hospital of Bonn, performed the treatment on a patient with metastatic thyroid cancer at that time.
Treatment of benign thyroid tumours with radioactive iodine began in Germany in 1950 in Hamburg. Since then, this procedure has been performed millions of times worldwide. Over the years, tens of thousands of patients who have undergone radioactive iodine treatment have been the subject of extensive scientific research. In this context, virtually no adverse effects of radioactive iodine therapy were found, and the treatment was successful in most cases.
In Germany, around 60,000 radioiodine therapy sessions are performed each year. Due to strict government requirements, the number of specialised centres is limited. There are only around 150 such centres in Germany.
What is radioactive iodine therapy?
Radiative iodine therapy is the most common form of radioisotope therapy. During the procedure, the patient receives radioactive iodine in the form of an aqueous solution or capsule. "Radioactive iodine" refers to the radioactive isotope of this substance, iodine-131, but the body cannot distinguish it from ordinary iodine.
The iodine is transported via the bloodstream to the thyroid gland, which rapidly accumulates and stores it. Once the iodine reaches the damaged thyroid cells, it releases radioactive energy, ultimately destroying them.
The half-life of iodine-131 is eight days. During this time, 50% of the administered iodine breaks down into other components. In addition to physical decay, the body also excretes iodine, which shortens the effective half-life.
Why does the thyroid gland store iodine?
The thyroid gland regulates the body’s hormonal balance. It produces hormones (T3 and T4) using iodine obtained from food, which stimulate the body’s metabolism. This process is controlled by the pituitary gland. When necessary, the pituitary gland releases thyroid-stimulating hormone (TSH), which stimulates the production of thyroid hormones.
Who is a candidate for radioiodine therapy?
In certain cases, the pituitary gland cannot control the production of thyroid hormones. This causes the thyroid gland to enlarge and produce hormones uncontrollably, regardless of the body’s needs or the pituitary gland’s regulatory signals. Radioiodine therapy safely removes the abnormal thyroid tissue.
Radioiodine therapy is performed:
- As an additional treatment for thyroid cancer and its metastases (only in cases of differentiated thyroid cancer).
- For benign thyroid nodules that produce hormones uncontrollably (thyroid adenomas).
- For cases of immune-related inflammation, such as Graves' disease.
- For an enlarged goiter, which usually does not affect metabolism but, due to excessive growth of thyroid tissue, can lead to difficulty swallowing and present an aesthetic concern, treatment options are available.
No preoperative surgery is required, except in cases of thyroid cancer. In cases of thyroid cancer, radioactive iodine therapy is prescribed after surgery to remove residual thyroid tissue and any possible metastases.
How is radioiodine therapy performed?
The procedure itself is generally brief and simple, and it is always the same regardless of the condition being treated. Although the radiation from the iodine used extends only a few millimeters, there is a theoretical risk of harming those nearby. This is because, as radioactive iodine decays, it releases beta radiation, which is used for therapeutic purposes, as well as gamma radiation, which has a much longer range. For this reason, treatment is conducted on an inpatient basis, and visiting patients during treatment is prohibited.
Water used in the clinic for domestic purposes (e.g., toilets and showers) flows into a special storage tank where it is kept until the radiation ceases to be active.
On the first day of the hospital stay, the doctor explains the procedure to the patient, uses an ultrasound to monitor the size of the gland, and definitively determines and records laboratory values. A thyroid scintigraphy is performed before admission to the clinic.
To see how active the thyroid gland is, the patient first takes a test capsule. Only after this does the patient receive a therapeutic capsule or liquid containing radioactive iodine.
The length of the hospital stay is regulated by law and is at least 48 hours. Besides that, doctors constantly check how much radiation is left in your thyroid. It can't go over a certain safe limit. Because of this, your hospital stay might sometimes stretch to several weeks.
Radiotherapy is effective for about 90% of people, and it generally has very few side effects. After discharge, patients can immediately return to their daily routines.
Side Effects of Radioiodine Therapy
Just like with other treatments, radioiodine therapy can have side effects. Within two weeks of treatment, about 70% of patients will see some temporary changes in their blood tests. Around 10% to 40% of people might get some swelling and discomfort in their neck.
Sometimes, if you get a higher dose of radioactive iodine, your mouth might feel dry for a bit. About one-third of patients might also experience inflammation in their salivary glands or stomach. A few people also find their eyes get dry while they're having treatment.
A certain proportion of patients develop hypothyroidism after completing therapy. However, this is not dangerous because the missing hormones can easily be replaced with medication that has no side effects.
Contraindications
Radioiodine treatment isn't safe for women who are pregnant or breastfeeding. To prevent pregnancy, the use of contraceptives is recommended for 6–12 months following treatment.
Do you need advice on radioiodine therapy? Book an appointment now to receive:
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