What to Expect from Radiation Treatment for Your Hyperthyroid Cat

If the veterinarian has diagnosed your cat with a thyroid tumor, you now realize that the insatiable appetite and nervous behaviors you once thought were just quirks in your pet were actually being caused by the changes in your cat's metabolism because of the disease. If you're considering radiation treatment to completely remove the tumor, here is how that treatment can cure your cat's hyperthyroidism and what to expect during and after treatment.

Getting the Radiation to Target the Thyroid Tumor

Your cat will be injected with radioactive iodine, which circulates through the bloodstream. The thyroid gland naturally absorbs iodine and will take the radioactive material into its tissues. The tumor cells rapidly reproduce and are the most active cells in the thyroid. These are also the cells which will absorb the majority of the radioactive iodine. The iodine will bind with the cancerous cells and kill them. The iodine that doesn't get absorbed by the tumor is flushed out of the cat's body through its urine.

When sufficient cancer cells have been killed, healthy thyroid cells take over the hormone production. Soon after the radiation treatment, your cat's body will return to its normal metabolism and your cat should lose the hyperactive behaviors.

How the Treatment Is Managed

Your cat will require a minimum of an overnight stay in the animal hospital. But it may need to stay a few days, depending on the size and weight of your cat and the amount of iodine given.

The iodine injection takes only a few minutes. After that, the veterinarian staff will monitor your cat's urine output for radiation levels. The radiation level decreases over time, and your cat will be released to go home when the level is safe for it to be discharged. A large cat will be given a higher dose of the radioactive iodine, and it will take longer for the radiation level to decrease to safe levels in its urine.

Taking Your Cat Home

When you arrive to pick up your cat, the staff at the clinic will give you special instructions as to how to handle your cat for the next few days. While the radiation in your cat is not particularly harmful to you in the short term, the clinic will be concerned about the accumulative effect on you over the next few days and weeks. The precautions are to keep you, your family, and other pets in the household safe from the long-term exposure to the small amounts of radioactivity.

Some of the instructions you'll be given include these:

  • Keep your cat away from people and other pets for several days.
  • Limit your own time with your cat to a few minutes each day.
  • Wash your hands thoroughly after being around your cat.

You'll be given special instructions for dealing with the cat litter, such as these:

  • Scoop the cat litter into a large bucket lined with a heavy trash can liner.
  • When the bucket is full, seal it with a lid and tape and store it in a safe place where it will be undisturbed.
  • Your vet will tell you when it's safe to put the litter bucket out with the trash.

Your cat will have a follow up appointment with the clinic a couple of weeks after the treatment. The vet will measure your cat's urine for radiation and tell you when you can stop the precautions. For further questions or information, contact an establishment like the Seattle Emergency Veterinary Hospital.