Home Articles Hot Thyroid Nodule vs Cold Thyroid Nodule
Hot Thyroid Nodule vs Cold Thyroid Nodule
Sunday, 12 February 2012 11:32

It is common for doctors to order a radioisotope scan of your thyroid. Taking a very small oral dose of radioactive I123 or I131 can help doctors analyze the function of the thyroid and thyroid nodule tissue. Knowing that most thyroid nodules are benign (non-cancerous) it is unnecessary to do surgery on all nodules. Imaging the thyroid with a radioactive isotope I123 or I131 can show if a nodules is functioning as normal thyroid tissue or abnormal thyroid tissue (possibly cancer.) as compared with the surrounding tissue. Hyper-functioning (usually normal) thyroid tissue produces a “hot” scan. Hot scans are usually not cancerous. Abnormal or nonfunctional (hypo-functioning) thyroid tissue produces a “cold” scan. A “warm” scan is somewhere in-between.


Hot Nodule - excess uptake of I131, hyper-functioning thyroid tissue: Cancer in 5-9% 4

Warm Nodule - moderate uptake of I131:  Cancer in 5-9% 4

Cold Nodule - no uptake of I131, hypo-functioning thyroid tissue: Cancer in 15-20%  4



So a nodule that is a cold nodule has a 2-3 times higher risk of being cancerous when compare to a hot or warm nodule. This helps your doctor analyze your risks level and helps define how aggressive your treatment needs to be.


This is not an end all definitive test because hot, warm, or cold scan can all turn out to be cancer or turn out to be normal. A thyroid radioisotope scan can not diagnose thyroid cancer. The scan helps guide the doctors with one's treatment plan. But remember, having a hot nodule means one is at a very low risk of the nodule being cancer. Most hot and warm nodules are not cancer. Doctors are more concerned about the cold nodules.


HOT NODULE = low risk of nodule being cancer

WARM NODULE = low-moderate risk of nodule being cancer

COLD NODULE = moderate risk of nodule being cancer



Most thyroid nodules produce a cold scan and 15-20% of cold scan thyroid nodules are cancerous4. But remember 95% of all nodules are benign (not cancer). So just because one gets a cold scan it does not mean they will have thyroid cancer. A cold scan simply puts one at a higher risk of having thyroid cancer.

hot thyroid nodule

cold thyroid nodule

Last Updated on Friday, 11 January 2013 17:26

thyroid cancer calculator

dropbox image



   low iodine diet grocery list small

Download Free!

Low Iodine Diet

Grocery List