Diagnosis and Treatment for Hyperthyroidism
Diagnosis of hyperthyroidism
If your healthcare provider suspects you have hyperthyroidism, or excess production of hormones by the thyroid gland, they may recommend that you first get a blood test that measures your levels of T-3, T-4 and thyroid-stimulating hormone (TSH). High levels of T-4 and low levels of TSH are often seen in people with hyperthyroidism. If the blood test confirms hyperthyroidism, your healthcare provider may send you to ARA to get further tests.
Radioiodine I-123 scan and uptake test
For this exam, you will come to the imaging center and take a small amount of a radiopharmaceutical called radioiodine I-123, by mouth. Then you will return to the imaging center twice (once after 4 hours for a 15-minute appointment and once after 24 hours for a 45-minute appointment) to get readings and a scan of your thyroid which will enable your radiologist to make a diagnosis.
This exam uses sound waves to evaluate abnormalities of the thyroid gland. It is especially useful for finding nodules. Thyroid ultrasound may be used for people who are pregnant or breastfeeding, since there is no radiation involved.
If your scan indicates that you would benefit from treatment for hyperthyroidism, your radiologist and your health care provider may recommend a safe and effective treatment called radioiodine therapy, which is available at ARA.
Treatment of hyperthyroidism with radioiodine therapy
Radioiodine (radioactive iodine) therapy is a molecular radiology treatment that uses a radioactive form of iodine called iodine-131 (I-131) to destroy abnormal thyroid cells and reduce the production of thyroid hormones. It is often recommended as a first line of treatment for hyperthyroidism.
How does radioactive iodine therapy work?
Radioiodine therapy works by taking advantage of the fact that thyroid cells are very efficient at absorbing and storing iodine from your diet. When you swallow a capsule or liquid containing I-131, it travels through your bloodstream and reaches your thyroid gland. There, it is taken up by the thyroid cells and emits radiation that damages or kills them, reducing or normalizing your hormone levels.
The amount of radiation delivered by I-131 depends on the dose you receive and how much iodine your thyroid cells take up. The dose is calculated based on your body weight, age, type and extent of your thyroid issue, and other factors. Your healthcare provider will monitor your response to the treatment using blood tests and scans.
The radiation from I-131 has a very short range, so it mainly affects your thyroid gland and nearby tissues. Most of the excess I-131 that is not absorbed by your thyroid is eliminated from your body through urine within a few days.