Radioactive iodine (I-131) can be used in medical therapies as a treatment and a diagnostic tool. It is most commonly used in the treatment of hyperthyroidism due to Graves’ disease or a nodule in the thyroid gland. I-131 can be therapeutically administered as a single capsule that is to be taken orally.
What is iodine 131 used for?
Iodine-131 is used to treat hyperthyroidism and thyroid cancer. For diagnostic purposes, it is used in a specialized imaging procedure known as a thyroid scan. During this type of procedure, a device uses small amounts of radiation to produce images of the thyroid gland. These images help the doctor assess the degree of functionality of the gland.
What is the effect of iodine on thyroid?
Those at the highest risk include ( 4, 5, 6 ):
- Pregnant women.
- People who live in countries where there is very little iodine in the soil. This includes South Asia, Southeast Asia, New Zealand and European countries.
- People who don’t use iodized salt.
- People who follow a vegetarian or vegan diet.
What is the half life of iodine 131?
Research shows that iodine can aggravate the overproduction of thyroid hormones in hyperthyroidism. Consuming a low-iodine diet is essential for managing thyroid hormones. Too much caffeine can cause insomnia, anxiety, restlessness, and heart palpitations.
Is iodine bad for hyperthyroidism?
How is iodine-131 used in diagnosis?
I-131 is a radioactive iodine salt that alters the mechanism of iodine absorption in the thyroid gland. Its use is particularly useful in the destruction of cells in the thyroid gland that are overactive. It can also be used in diagnostic imaging techniques used for pheochromocytoma and neuroblastoma.
How does iodine-131 treat Graves disease?
Radioactive iodine 131I (RAI) treatment is an effective definitive treatment of hyperthyroidism, used as a first line or second line treatment for over six decades, 131I being selectively concentrated by functioning thyroid tissue that subsequently is destroyed over weeks by beta-radiation [1,2,3].
Why is iodine-131 used in thyroid cancer?
It uses a radioactive form of iodine called iodine 131 (I-131). It is a useful treatment in thyroid cancer because the thyroid gland absorbs and stores most of the iodine in your body. The thyroid gland gets iodine from certain foods and uses this to make essential thyroid hormones.
What is iodine therapy used for?
Radioiodine therapy is used to treat hyperthyroidism and thyroid cancer. Hyperthyroidism occurs when your thyroid gland makes excess thyroid hormones. Radioiodine treats this condition by killing overactive thyroid cells or by shrinking an enlarged thyroid gland.
Is radioactive iodine used to treat Graves disease?
Radioactive iodine (I131) is a common definitive treatment for Graves' Disease. Potential complications include worsening, or new development of Graves' eye disease and development of a radiation thyroiditis.
What are the benefits of iodine-131 in treating goiter?
Summary: The benefits of I-131 remnant ablation include: [1] facilitating the interpretation of subsequent serum thyroglobulin levels, [2] increasing the sensitivity of detection of locoregional and/or metastatic disease on subsequent follow-up radioactive iodine whole-body scans, [3] maximizing the therapeutic effect ...
Which radioisotope is used for diagnosing thyroid disorders?
Radioactive iodine takes advantage of the fact that thyroid cells and thyroid cancer cells absorb iodine; therefore, it has been used to diagnose or treat various thyroid disorders. Iodine is made into two radioactive isotopes, I-123 and I-131, that are commonly used in patients with thyroid disease.
What is iodine 131 used for?
Iodine-131 Medical Use. Radioactive iodine (I-131) can be used in medical therapies as a treatment and a diagnostic tool. It is most commonly used in the treatment of hyperthyroidism due to Graves’ disease or a nodule in the thyroid gland.
What is 131 used for?
Its use is particularly useful in the destruction of cells in the thyroid gland that are overactive. It can also be used in diagnostic imaging techniques used for pheochromocytoma and neuroblastoma.
What is the use of beta radiation?
It can also be used in diagnostic imaging techniques used for pheochromocytoma and neuroblastoma. It is the beta radiation from I-131 that provides the therapeutic benefit of the treatment. The majority (90%) of the effect is carried out by this radiation, although the gamma radiation also plays a role.
Can I-131 be taken orally?
Administration. I-131 can be therapeutically administered as a single capsule that is to be taken orally . The radioactive iodine emits both beta and gamma radiation. The beta radiation is the active agent that kills the overactive thyroid cells and travels small distances, not usually exiting from the patient’s body.
Is radioactive iodine safe for hyperthyroidism?
Treatment with radioactive iodine in therapeutic doses is well tolerated and is considered to be a safe and effective treatment for hyperthyroidism. The most common adverse effect is hypothyroidism, due to the excessive destruction of thyroid cells that lead to under activity of the gland.
What is radioactive iodine?
Radioactive iodine (I-131) Therapy for Thyroid Cancer. Radioactive iodine (RAI) is a therapy used in the treatment of some thyroid cancers, specifically papillary and follicular thyroid cancer. For the thyroid gland to make thyroid hormone, the first step in the process is for the thyroid cells to "take up" iodide from the bloodstream.
How long before I-131 injections?
You may receive injections of a medication called Thyrogen over two days prior to your I-131 therapy. Thyrogen is recombinant TSH and these injections will elevate the TSH level in your blood, which in turn stimulates the thyroid cells to take up the I-131.
What is the first step in thyroid hormone production?
TSH is what signals the thyroid cells to produce thyroid hormone and, as discussed above, the first step in thyroid hormone production is for the thyroid cells to take up iodide from the bloodstream. Therefore, to maximize the amount of I-131 that enters the thyroid cells, your TSH level must be high.
What is RAI for thyroid cancer?
RAI for remnant ablation destroys any residual normal thyroid tissue, allowing your physicians to more easily detect if your thyroid cancer comes back . A blood test called thyroglobulin is used in surveillance monitoring of thyroid cancer.
How long after I-131 treatment can I go home?
After the whole body scan is completed, you will then receive the oral I-131 treatment pill. After taking the I-131, you will be sent home or, rarely, you may be required to remain in the hospital for a few days . You will be asked to return to the nuclear medicine department 7-10 days later to have another whole body scan, also known as the "post-therapy scan," that will show where the I-131 was deposited in your body. This scan may also identify any new sites of iodine-avid thyroid cancer not seen on the first whole body scan.
How long does it take for I-131 to work?
To prepare you for I-131 therapy and to maximize the effects I-131, there are two things that must happen. First, you must follow a low iodine diet for 1-2 weeks to deplete your body of iodine. Iodine is found in many foods that we eat. This will make your thyroid cells "hungry" for the I-131 and help to increase the amount ...
How long after I-131 can I breastfeed?
Men should not father a child for at least 3 months after treatment. Women should not breastfeed after I-131 treatment; but may be able to breastfeed with future pregnancies.
Why is 131 I used for thyroid cancer?
For this reason, 131 I is used for the treatment of thyrotoxicosis (hyperthyroidism) and some types of thyroid cancer that absorb iodine.
Why is 131 I given?
131 I therapy is given postoperatively for three reasons: it destroys normal thyroid remnants, thereby increasing the sensitivity of subsequent 131 I total body scans and the specificity of measurements of serum thyroglobulin for the detection of persistent or recurrent disease; it may destroy occult microscopic carcinoma, thereby decreasing the long-term recurrence rate , and it permits a postablative 131 I total body scan, a sensitive tool for persistent carcinoma.
How long does 131 I last?
The 131 I isotope has a half-life of 8 days and emits γ radiation and β particles. Given orally, it is concentrated in the thyroid, where the β particles destroy the gland. Symptoms of hyperthyroidism begin to improve in a few days to a few weeks, but 2 to 3 months are often required for a complete effect.
How long does it take for 131 I to work?
This may be achieved by rendering the patient either euthyroid or hypothyroid. 131 I typically takes 6 to 8 weeks to produce its effects, and euthyroidism is expected 3 to 6 months after 131 I administration.
Is MIBG 131 I still in the experimental stage?
131 I-MIBG therapy is still in the experimental stage. It can be considered as an option in chemotherapy-resistant tumors and patients where chemotherapy doses cannot be increased due to clinical limitations like decreased hematopoiesis, mucosal toxicity, and so on. Other therapy options are required in cases of high-risk neuroblastoma. When 131 I is tagged with MIBG, it selectively targets tumors cells with limited effect on normal cells. In many cases, the therapeutic dose of 131 I-MIBG diagnosed new metastatic lesions, which was not seen previously in the diagnostic 131 I-MIBG scan ( Fig. 8.6) [87–89]. Previous studied demonstrated a 37% response rate in relapsed cases of neuroblastoma [90]. Another study showed stable disease in 34% of patients [91].
Is 131 I a thyroid hormone?
Because adequate thyroidal io dine (and hence 131 I) uptake is a prerequisite for 131 I therapy, it is not an appropriate treatment modality for thyroid-stimulating hormone (TSH)-dependent hyperthyroidism and for other causes of hyperthyroidism with low iodine uptakes such as thyroiditis.
Is 131 I ablation safe?
In low-risk patients, the long-term prognosis after surgery alone is so favorable that 131 I ablation is not usually recommended. However, patients who are at high risk of recurrence are routinely treated with 131 I, because it decreases both the rate of recurrence and the rate of death. Table III.
What is radioactive iodine?
Radioactive Iodine I-131 (also called Radioiodine I-131) therapy is a treatment for an overactive thyroid, a condition called hyperthyroidism. Hyperthyroidism can be caused by Graves' disease, in which the entire thyroid gland is overactive, or by nodules within the gland which are locally overactive in producing too much thyroid hormone.
What is radioiodine therapy?
Settings. Fullscreen. Radioiodine therapy is a nuclear medicine treatment for an overactive thyroid, a condition called hyperthyroidism, and also may be used to treat thyroid cancer. When a small dose of radioactive iodine I-131 (an isotope of iodine that emits radiation) is swallowed, it is absorbed into the bloodstream and concentrated by ...
What is the name of the isotope of iodine that is absorbed into the bloodstream
When a thyroid gland is overactive, it produces too much of these hormones, accelerating the metabolism. Radioactive iodine (I-131), an isotope of iodine that emits radiation, is used for medical purposes. When a small dose of I-131 is swallowed, it is absorbed into the bloodstream in the gastrointestinal ...
How long does it take for iodine to leave the body?
The majority of the radioactive iodine that has not been absorbed leaves the body during the first two days following the treatment, primarily through the urine. Small amounts will also be excreted in saliva, sweat, tears, vaginal secretions, and feces.
Where is radioiodine 131 absorbed?
The radioiodine I-131 is swallowed in a single dose, in capsule or liquid form, and is quickly absorbed into the bloodstream in the gastrointestinal (GI) tract and concentrated from the blood by the thyroid gland, where it begins destroying the gland's cells.
Where is I-131 absorbed?
When a small dose of I-131 is swallowed, it is absorbed into the bloodstream in the gastrointestinal (GI) tract and concentrated from the blood by the thyroid gland, where it begins destroying the gland's cells. Radioactive iodine I-131 may also be used to treat thyroid cancer. top of page.
How long after I-131 can I breastfeed?
Also, it is recommended that pregnancy be delayed until at least six to 12 months after I-131 treatment.
Administration
Pharmacology
- I-131 is a radioactive iodine salt that alters the mechanism of iodine absorption in the thyroid gland. Its use is particularly useful in the destruction of cells in the thyroid gland that are overactive. It can also be used in diagnostic imaging techniques used for pheochromocytoma and neuroblastoma. It is the beta radiation from I-131 that provid...
Adverse Effects
- Treatment with radioactive iodine in therapeutic doses is well tolerated and is considered to be a safe and effective treatment for hyperthyroidism. The most common adverse effect is hypothyroidism, due to the excessive destruction of thyroid cells that lead to under activity of the gland. Some patients with severe hyperthyroidism may experience worsening of symptoms imm…
Post-Treatment Isolation and Monitoring
- Due to the exposure to I-131 in patients receiving therapeutic doses, there is a need for some level of isolation following therapy to minimize the risk to surrounding individuals. The majority of the radioactive iodine is eliminated from the body through natural decay in the first 3-5 days following administration, with total elimination several weeks later. The following methods help to reduce …
References
Further Reading
Remnant Ablation
- RAI for remnant ablation destroys any residual normal thyroid tissue, allowing your physicians to more easily detect if your thyroid cancer comes back. A blood test called thyroglobulin is used in surveillance monitoring of thyroid cancer. Thyroglobulin is a protein that is only produced by either normal thyroid cells or thyroid cancer cells. After surgery you may still have a small amount of n…
Rai Effect on Cancer Cells
- Some thyroid cancer cells also share the same ability as normal thyroid cells to take up iodine from the bloodstream. These are referred to as "iodine-avid". If your cancer cells are able to do this, then I-131 may also destroy microscopic residual thyroid cancer cells or be used as a treatment for thyroid cancer that has spread to lymph nodes or o...
Preparing For Treatment
- Although I-131 is a pill, you cannot simply take the pill without prior preparation. To prepare you for I-131 therapy and to maximize the effects I-131, there are two things that must happen. First, you must follow a low iodine diet for 1-2 weeks to deplete your body of iodine. Iodine is found in many foods that we eat. This will make your thyroid cells "hungry" for the I-131 and help to incre…
Treatment Procedure
- Prior to treatment, patients will have a "whole body scan" that is performed one day after taking a small dose of a different radioiodine isotope (I-123). I-123 does not destroy thyroid cells and will allow your treatment team to visualize the location and amount of any remaining thyroid remnant and possibly thyroid cancer. After the whole body scan is completed, you will then receive the or…
Safety After Treatment
- I-131 remains in your system for up to a few weeks and excess not taken up by the thyroid is excreted in urine, stool, saliva and perspiration over the first 1-2 days following treatment. As the radioactivity of the I-131 in your system is a concern for those around you, you need to follow radiation safety precautions after receiving I-131. The length of time one has to follow these pre…
Resources For More Information
- ThyCa: Thyroid Cancer Survivors' Association, Inc. National Cancer Institute Thyroid Cancer Page American Thyroid Association Radioactive Iodine FAQ's