Therapy with radioactive iodine is used in diseases of the thyroid gland, which cause this organ to become overactive. Radioactive iodine-131 is an alternative to surgical treatment, and its goal is to inhibit the overproduction of thyroid hormones. Check what is the treatment with radioactive iodine, what are the indications for its use and what side effects may be.
Radioactive iodine treatmentis usedin diseases of the thyroid glandto suppress the thyroid gland and thus reduce the secretion of hormones by this organ.
The radiation emitted by 131I acts on the cells of the thyroid gland. As a result of this interaction, they partially destroy them and, as a result, inhibit the secretion of hormones. An additional effect of radioiodine treatment is the reduction of the size of the entire gland.
Treatment with radioactive iodine - indications
Iodine treatment 131is indicated in diseases of the thyroid gland in the course of which there is an overproduction of thyroid hormones, i.e. hyperthyroidism. These are mainly Graves' disease, nodular (nodular) thyroid goitre, and toxic adenoma. It is also used in diseases that are not related to hyperthyroidism, but that involve pressure goiter on the trachea.
Iodine treatment of the thyroid glandis an alternative to surgical treatment.
- In the treatment of hyperthyroidism, the iodine131I radioisotope can be used, which accumulates in the thyroid nodules or parenchyma and gradually eliminates cells that produce excessive amounts of hormones - says prof. Bożena Birkenfeld from the Department of Nuclear Medicine, Pomeranian Medical University in Szczecin.
- The decision on radioisotope or surgical treatment is made when pharmacological treatment does not help or is insufficient. Which method of treatment will be used depends largely on the patient's own decision: whether he prefers to swallow a capsule with radioactive iodine and return home, or for some reason he will decide to undergo an anesthetic operation and stay in hospital - explains Prof. Bożena Birkenfeld.
- Both radioisotope treatment and surgery can lead to a situation where the thyroid hormones will not be enough in the body (hypothyroidism will develop) andyou will need to take them as tablets every day. In many cases, this is considered to be the desired effect of the therapy. Taking thyroid hormone pills does not cause any side effects if the dosage is correct. It is worth noting that currently the dosage of such drugs is very precisely monitored - says Dr. Maria Listewnik from the Department of Nuclear Medicine of the Pomeranian Medical University in Szczecin.
Radioactive iodine treatment - contraindications
The only contraindications for treatment with radioactive iodine are pregnancy and breastfeeding.
Radioactive iodine treatment - how to prepare?
A week (and in some cases even a month) before starting treatment, all anti-thyroid medications and other iodine-containing medications (e.g. fish oil) should be discontinued. Other medications (e.g. for high blood pressure, diabetes) should be taken as recommended
It is recommended to eat a light meal 2-3 hours before taking the iodine-131 capsule.
Radioactive iodine treatment - what is it?
1) Research
Before using radioiodine therapy, it is necessary to perform preliminary tests to determine whether treatment with 131I can be performed.
The tests include the determination of the concentration of thyroid hormones and antibodies in the blood, measurements of the ability to uptake radioactive iodine by the thyroid gland, scintigraphy (thyroid scintigraphy) and ultrasound of the thyroid gland (USG of the thyroid gland).
In selected cases, an additional fine-needle biopsy of the thyroid gland is performed in order to exclude the development of a neoplastic process in the patient's thyroid gland. The results of these tests are assessed by the attending physician during the qualifying visit for radioiodine therapy.
A specialist in nuclear medicine decides whether to qualify a patient for this treatment. The date of administration of a dose of radioiodine is determined individually with each patient.
2) Administer radioactive iodine
In women, a pregnancy test is performed before the administration of radioiodine (on the day of the planned treatment).
If symptoms of hyperthyroidism worsen a few days after taking iodine-131 (increased nervous excitability, fast or uneven heartbeat, sweating, trembling hands), see an endocrinologist or a nuclear medicine doctor .
Treatment consists in administering a capsule (similar in size and shape to capsules of popular antibiotics) with radioactive iodine-131, which must be swallowed. After entering the body, the radioactive iodine is taken up by the thyroid gland and the radiation destroys itoveractive tissue. In this way, the activity of the thyroid gland is inhibited, and hence - the production of hormones by this organ is reduced.
A large part of the radioactive isotope is captured by the thyroid gland and remains active there for about a few weeks. However, a portion of the administered radiopharmaceutical dose is excreted in urine, sweat and faeces in the first few days after treatment with 131I.
After administration of the preparation, the patient goes home - hospitalization is not necessary.
It is worth knowing that radioactive iodine is a drug produced and imported to nuclear medicine facilities in doses ordered individually for each patient based on previously performed tests and recommendations of a specialist doctor.
Diagnostics, administration of radioiodine and care for one year after the dose of 131I are administered on the basis of the contract of the given center with the National He alth Fund, therefore the patient qualified for the therapy is treated free of charge.
- During the tests, the doctor assesses the ability of the patient's thyroid to accumulate iodine (the human body absorbs radioactive iodine in the same way as iodine from other sources, such as sea fish). Ultrasound examination and scintigraphy of the thyroid gland are performed, as well as laboratory tests, including the concentration of anti-thyroid antibodies in the serum, and possibly a fine-needle biopsy to examine the nature of the detected nodules and exclude a tumor - says Prof. Bożena Birkenfeld.
3) Control visits
After the administration of the therapeutic dose of 131I, follow-up tests are performed to help assess the effectiveness of the treatment. The first check-up is carried out within one to three months after the treatment, the next check-ups are carried out after 6 and 10 months.
Occasionally an underactive thyroid becomes or a persistent hyperthyroidism occurs. The most common effect of this therapy is the achievement of normal thyroid function. The therapy can also be used in children and women in the reproductive period.
According to an expertDr. Maria Listewnik from the Department of Nuclear Medicine of the Pomeranian Medical University in SzczecinBoth radioisotope treatment and surgery may lead to the situation that there will be insufficient thyroid hormones in the body (hypothyroidism will develop) and it will be necessary to take them daily in the form of tablets. In many cases, this is considered to be the desired effect of the therapy. Taking thyroid hormone pills does not cause any side effects if the dosage is correct. It is worth noting that currently the dosage of such drugs is very carefully monitored.
ImportantA woman after treatment with radioactive iodine for 12 months should not become pregnant
You should use contraception for about a year after taking radioactive iodine to prevent pregnancy. It is the time necessary for the DNA of all reproductive cells damaged by harmful radiation to be repaired.
Radioactive iodine treatment - what to do after receiving radioiodine?
1. No food should be taken up to two hours after administration of the drug, but after this time you can eat as usual, there are no indications for dietary restrictions. This is an undoubted advantage of radiopharmaceutical therapy - the patient does not have to deal with additional restrictions.
A person treated with radioactive iodine is on sick leave. Radiation from the dose taken does not pose a threat to the patient, nor does it pose a threat to people from the patient's close environment, provided that medical recommendations are followed.
2. For a few days (3-4) you should:
- minimize staying in the same room with other members of the household
- drink plenty of fluids to quickly remove radioiodine from the body that is not captured by the thyroid gland
- sucking on candy or chewing gum to reduce iodine build-up in your salivary glands
- flush toilet twice
- thoroughly wash the bathtub or paddling pool after bathing
- wash your hands often
- abstain from sexual intercourse
- sleep in a separate bed
- underwear and bed linen should be washed separately and rinsed thoroughly
Avoid close contact with children and pregnant women for at least 2 weeks
After the administration of radioactive iodine, the patient emits radiation (its intensity depends mainly on the dose received by the patient) until the radioiodine is not excreted from the body, which lasts about 2 weeks. Does it pose a threat to the environment? If you pass someone in the corridor, stand next to you on the bus or even shake your hand, it is not a threat. However, being close to a person after radioactive iodine treatment for more than 24 hours can be dangerous. For this reason, a person who has undergone this type of therapy should limit contact with household members to a minimum. The precautions apply especially to children and pregnant women, as for them radioactive iodine is particularly dangerous. Close and long-term contact with pregnant women and young children (cuddling, sleeping in one bed, etc.) should be avoided for a minimum of two weeks after radioiodine administration.