Radioactive iodine uptake test

Radioactive iodine uptake test

A radioactive iodine uptake test also called a thyroid uptake test, can help check thyroid function and find the cause of hyperthyroidism. The thyroid “takes up” iodine from the blood to make thyroid hormones, which is why this is called an uptake test. Your health care professional may ask you to avoid foods high in iodine, such as kelp, or medicines containing iodine for a week before the test.

Swallow a small amount of radioactive iodine: For this test, you will swallow a small amount of radioactive iodine in liquid or capsule form. During the test, you will sit in a chair while a technician places a device called a gamma probe in front of your neck, near your thyroid gland. The probe measures how much radioactive iodine your thyroid takes up from your blood. Measurements are often taken 4 to 6 hours after you swallow the radioactive iodine and again at 24 hours. The test takes only a few minutes.

 Graves’ disease: If your thyroid collects a large amount of radioactive iodine, you may have Graves’ disease, or one or more nodules that make too much thyroid hormone. You may have this test at the same time as a thyroid scan.

A small amount of radiation: Even though the test uses a small amount of radiation and is thought to be safe, you should not have this test if you are pregnant or breastfeeding.

Shorter half-life: 123I has a shorter half-life than 131I (a half day vs. 8.1 days), so the use of 123I exposes the body to less radiation, at the expense of less time to evaluate delayed scan images. Furthermore, 123I emits gamma radiation, while 131I emits gamma and beta radiation.

Inputs Courtesy: ENT Specialist Doctor with 41 years of experience. He can be reached Only on  WhatsApp messages at 9243301223.