From the Guidelines
It is generally okay to undergo an I-123 uptake scan even if you have Graves' eye symptoms, as the scan itself does not typically worsen eye symptoms and can help confirm a diagnosis of Graves' disease. The I-123 uptake scan is a diagnostic test that measures how much iodine your thyroid gland absorbs, and it is a useful tool in the initial imaging of thyrotoxicosis, including Graves' disease 1. According to the American College of Radiology, US thyroid, I-123 radionuclide uptake and scan neck, or I-131 radionuclide uptake and Tc-99m pertechnetate scan neck are usually appropriate for the initial imaging of thyrotoxicosis, and the nuclear medicine studies are procedures that are equivalent alternatives and complementary with US 1.
When considering the use of an I-123 uptake scan in patients with Graves' eye symptoms, it is essential to weigh the potential benefits and risks. The scan involves taking a small dose of radioactive iodine by mouth and then measuring the uptake in your thyroid after 4-6 hours and again at 24 hours. No special preparation is needed except avoiding iodine-containing foods, supplements, and medications for 1-2 weeks before the test. Unlike radioactive iodine treatment (I-131), which is used to treat hyperthyroidism and can potentially worsen eye symptoms in some patients, the diagnostic I-123 scan uses a much lower dose of radiation and is not known to exacerbate thyroid eye disease.
Some key points to consider when undergoing an I-123 uptake scan with Graves' eye symptoms include:
- Informing your healthcare provider about your eye symptoms before the test, as they may want to coordinate your care with an ophthalmologist
- Avoiding iodine-containing foods, supplements, and medications for 1-2 weeks before the test
- Understanding that the scan itself does not typically worsen eye symptoms, but it is crucial to follow up with your healthcare provider to discuss the results and any potential implications for your eye symptoms. As stated in the acr appropriateness criteria, thyrotoxicosis may present with symptoms of hyperthyroidism, and imaging with an iodine uptake and scan can help confirm the cause for thyrotoxicosis, including Graves' disease 1.
From the Research
I-123 Uptake Scan with Graves' Eye Symptoms
- There is no direct evidence in the provided studies that discusses the safety or feasibility of performing an I-123 uptake scan in patients with Graves' eye symptoms.
- However, the studies suggest that patients with Graves' disease, which often presents with eye symptoms, can undergo various diagnostic tests, including CT and MRI scans, to evaluate the severity of their condition 2.
- Radioactive iodine (RAI) therapy is a common treatment for Graves' disease, but it can exacerbate or trigger Graves' ophthalmopathy in some patients 3, 4.
- The management of Graves' orbitopathy typically involves a multi-specialty team and may include local therapies, selenium, intravenous glucocorticoid therapy, and other treatments 5.
- While there is no specific information on I-123 uptake scans, the studies emphasize the importance of careful evaluation and management of patients with Graves' disease and eye symptoms to prevent complications and improve outcomes 2, 3, 6, 4, 5.