treatment is a single injection of Radioisotope (I-131). The iodine
is absorbed by the thyroid tumor and the tumor is destroyed in
almost all cats treated. The cat does not require anesthesia or any
other invasive procedure besides the one injection. There are
usually no harmful side effects. Healthy thyroid tissue and the
associated parathyroid glands are not destroyed. Within one to three
months thyroid function should return to normal. No thyroid
supplementation is normally required. We suggest that your cat be
taken to your veterinarian for re-evaluation one month after
A complete physical exam of your cat is required by your veterinarian with T3 and T4 values taken within 2 weeks of treatment. Also, your veterinarian must x-ray the heart and lungs to evaluate heart size and any possible lung malignancy. It is important that the T3 and T4 blood samples are taken after several days of being off the Tapazole, unless there is a pre-Tapazole T4.
The state has very rigid requirements on the exposure of humans to any radioisotope. After the I-131 is administered to your cat, attendants and veterinarians can only feed the animal, clean the cage and evaluate the cat's physical condition. The long exposure needed for any special treatment would be prohibitive. We adjust room temperature accordingly, leave the lights on and play soft music in the isolation area.
The cat must remain in isolation until the level of radiation is safe. This level is usually reached within four days or less. After the cat is released, A few precautionary measures should be taken for the next 2 weeks. We suggest that litter pan liners be used in the litter box and disposable gloves be worn when cleaning the box. It is best not to let your cat sleep with you or snuggle up too long for this 2 week period. After any close contact, it is wise to wash hands. It is best for pregnant women and children not to care for the cat during this 2 week period. The regulation for using I-131 on animals is much more rigid than when used on people. Very likely one would receive more radiation from a day in the sun than would be received from the cat at this point, but it is best to follow regulations.
For any firther information on the treatment and length of time the cat must be in our isolation, please call us at (708) 349-8222
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