The thyroid uses the iodine to create the thyroid hormones. With little iodine, the cells cannot produce enough hormone. The pituitary, another gland in the brain, sends a signal to the thyroid to try to make more hormones. In doing so, the thyroid can grow or enlarge in an attempt to make more cells to create more T3 and T4 hormones.
Because the thyroid is the only type cell to uptake iodine, for over 50 years doctors have used radioactive iodine to essentially poison and kill and remaining thyroid cells, whereever they are in your body.
Radioactive iodine treatment is recommended for anyone who has had thyroid cancer with a total thyroidectomy.
The process works as follows:
1. In order for the radioactive iodine treatment to be effective and destroy any remaining thyroid tissue, the levels of TSH (thyroid stimulating hormone), secreted by the pituitary gland must rise to elevated levels.
2. For the levels of TSH to rise, the levels of thyroid hormone must have dropped to very low levels, which makes the pituitary create more TSH in an attempt to have the thyroid create more thyroid hormones.
3. The TSH stimulates the remaining thyroid cells to take up the radioactive iodine. This happens wherever they may be in the body--residual tissue in the neck area that was not removed, to stray cancerous thyroid cells that broke off and have been transported to other parts of the body.
4. Thyroid hormone has a long half life--so it takes many weeks for thyroid hormone levels to drop and TSH levels to rise.
5. Normally it takes from 3-5 weeks for all of this to happen.
6. To avoid prolonged hypothyroidism, some patients will take T3, which must be stopped ~ 14 days prior to the radioactive iodine treatment.
7. The doctor gives the patient a radioactive iodine pill, which is swallowed. The starving thyroid cells ravenously absorb the radioactive iodine, and are killed.
Precautions need to be taken to avoid contact with other individuals for several days, after radioactive iodine treatment. The radioactivity is not harmless. The benefits to the patient far outway the risks, but there is a risk to others who may become in contact with the radiation.
Note: Thyrogen is a synthetic form of TSH that was approved by the FDA.
just three days after my surgery on 12/17/07. Thyrogen can be used instead
of stopping the thyroid hormones for several weeks. Going for weeks
without thyroid hormones has many negative side effects, such as being tired,
decreased heart rate, decreased metabolism (increased weight gain), among
others. The use of thyrogen avoids these side effects, because the
thyroid hormones are never stopped. However, in tests, there is a
slightly better success rate in doing reducing thyroid hormones compared to the
use of thyrogen. When dealing with cancer, my opinion is to take
every extra step possible