Saul Marcus, ND - Naturopathic Doctor

257 West 39th street, 10th floor - New York, NY 10001

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Should I get a radioiodine uptake scan (RAI-U)?

In a radioiodine uptake scan (abbreviated RAI-U) the patient swallows radioiodine. Since the thyroid takes in more iodine than other organs, it can then be scanned to see how much iodine was taken up, and if concentrated in any areas.

An elevated RAI-U is associated with Graves' disease, iodine deficiency and other less common illnesses.

Nodules can also be seen on the uptake scan as areas of higher concentration.

RAI-U test is often recommended in cases of hyperthyroidism. It can be used to different Graves' disease from other causes of hyperthyroidism such as a thyroid secreting nodule.

Image radioiodine uptake test

Patients are often concerned over exposure to radiation. In conventional medicine this test is considered safe and patients are told there are no side effects to worry about.

The only source I have found which actually discusses possible side effect of RAI-U test is the excellent book from Elaine Moore and Lisa Moore: Advances in Graves Disease and Other Hyperthyroid Disorders.

Key points to consider are:

  • Radiation may take years or decades to manifest as symptoms
  • No long term population studies have been done on those who have had the RAI-U test

Nonetheless, at times this can be a very important test to get done - such as when the diagnosis seems to be Graves' but is not. Antibodies that cause Graves' disease (TSI or thyroid stimulating immunoglobulin) could alternatively be tested instead of the RAI-U test.

Whether or not to have a RAI-U test should be considered on a case by case basis. Sometimes endocrinologist recommend the RAI-U test immediately after diagnosis of hyperthyroidism and other times they do not.

In my clients I have not noticed any consistency in terms of what endocrinologist recommend. Some patients are simply prescribed anti-thyroid medications based off of blood work and symptoms, and others are told to a RAI-U test right away.

With regards to this test, I try to guide people to the information they need, in order for them to make their best informed decision. I'm not against this test at all when needed, but at times suspect that it may be over utilized.