The technetium is selectively taken up
by abnormal thyroid tissue, and this can be detected using a special camera (a «gamma camera»).
Cats with this problem are best treated with radioactive iodine to
destroy abnormal thyroid tissue but they can also be managed with a medication called methimazole (Tapazole).
The antithyroid medications may decrease uptake by
the abnormal thyroid tissue, and therefore will decrease its effectiveness.
Medical management for any length of time can make therapy with radioiodine more difficult by allowing
the abnormal thyroid tissue to continue to grow which then requires higher doses of radioiodine and therefore a longer hospital stay for the cat.
The quantity of radiation destroys
the abnormal thyroid tissue but does not damage the surrounding tissues or the parathyroid glands.
When an injection of radioactive iodine is given, it destroys
the abnormal thyroid tissue without endangering other organs.
Treatment: The current treatment of choice is destruction of
the abnormal thyroid tissue with radioactive iodine (I131).
Not only is this test accurate in diagnosing the problem, it will also let us know if some of
the abnormal thyroid tissue has repositioned itself further down the chest.
Before your pet is treated with radioactive iodine we will test its kidney function with Tapazole to determine if kidney function will be adequate after the radioactive iodine destroys
the abnormal thyroid tissue.
The iodine will destroy
abnormal thyroid tissue, leaving surrounding tissues and parathyroid glands untouched and thus not causing any additional damage.
The iodine, which is required for the production of both T3 and T4, is taken up by the thyroid gland and the emitted radiation destroys
the abnormal thyroid tissue without damaging the surrounding tissues or the parathyroid glands.
Images of the thyroid gland are then acquired using a gamma camera to provide information on nodule size, the presence of single or multiple nodules, and the location of
the abnormal thyroid tissue.