For about a week before a thyroid scan, your doctor may ask you to avoid certain foods and medications that can interfere with the results, including thyroid hormones, T4 for 3 weeks, T3 for 10 days, multivitamins or any iodine products or supplements for 3 weeks, PTU or Tapazole for 3 days and shellfish for 3 days (which contain iodine).
No IV (iodine) contrast for 3 weeks (CT scan, IVP, Myelogram and MRI or CT Angiogram have iodine).
You might also need to have blood tests that check thyroid function.
If you have any question please call Nuclear Medicine department at 713 589 5228
