Thyroid Nodules (cont.)
- This test is performed by a nuclear medicine specialist. After a small,
safe amount of radioisotope (123-iodine or Tc99) is taken by mouth or injected into a
vein, the radiologist obtains pictures of the thyroid.
- Nodules can be seen as dark spots (called "cold," because they do not take up the radioisotope) or bright spots (called
"hot," because they do take up the radioisotope).
- Nodules that concentrate the radioisotope are "hot" and usually
make excessive thyroid hormone. "Hot" nodules are rarely associated with
cancer and may not require FNAB investigation.
- Nodules that do not concentrate iodine are "cold" and usually make
less than normal amounts of thyroid hormone
- More than 80% to 85% of all thyroid nodules are "cold."
- These nodules are typically more worrisome for cancer, and require
evaluation with FNAB or surgery.
Medically Reviewed by a Doctor on 5/20/2013
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