1-131 Therapy

This treatment works because iodine (radioactive or otherwise) attaches to thyroid tissue. Radioactive iodine emits high-speed electrons that damage the thyroid tissue from within, effectively destroying the thyroid tumor. The electrons only penetrate a fraction of an inch, which means only the thyroid tissue is affected, and the rest of the cat's body is not. Human beings with hyperthyroidism are similarly irradiated and are not confined in any way afterward, but because, in this situation, the patient is a cat, the Nuclear Regulatory Commission insists on confinement as described above. The potential for side effects with this therapy is very low, and it is low stress for the cat.

This therapy is generally considered the safest and most effective method of treatment for feline hyperthyroidism.

Your cat will be given an injection of radioactive iodine (iodine 131) and kept in the facility until the radiation levels have reduced adequately to allow the cat to return home (typically four days). Treatment is not invasive, and most cats tolerate brief separation from home without significant stress.

Your cat will be provided environmental enrichment during their I-131 vacation! They will have their own private condo, hide boxes, beds, toys, and separate area for their litter box. We have 24/7 cat TV where they can watch their favorites shows!

We know how hard it is to be separated from your kitty without being able to visit. The CASE I-131 facility has kitty cams so that you can check in and see what your cat is up to!

After release, there will be a period of time where the cat will need confinement, flushable cat litter, and restricted human contact because they are still emitting low levels of radiation. After this period, the cat is back to normal without restrictions, and all that is left to do is return for some follow-up lab work over the following few months. The radioactive iodine injection is given under the skin, similar to a vaccine, and the cat is basically boarding afterward until the radiation levels drop.

Advantages of this Method of Treatment

• Treatment is a one-time event (only two to four percent of cats require a second treatment), and no ongoing therapy is required.
• The disease is not simply managed but is actually cured!
• No anesthesia is required as treatment amounts to an injection followed by a short period of boarding, which is very non-stressful, especially considering the usual patient is an older cat with potential heart disease.

• Owner and pet are separated during the quarantine.
• Typically, facilities require the cat to be confined indoors or have limited contact with owners for a period of time after discharge. Children and pregnant women can have no contact with the cat for a week or two after therapy. If this is too inconvenient to work out at home, the cat may be boarded at the radiofacility until this period has passed, but there will be an additional expense for that.
• This is a relatively expensive therapy, and the facility's cost does not include the required pre- or post-treatment diagnostics.
• Special flushable cat litter is required for one to two weeks after therapy.
• Some follow-up blood testing is generally recommended after treatment (typically one and three months after therapy).
• There is a small chance that the cat will become hypothyroid after treatment, requiring daily oral thyroid hormone supplementation.
• Radiotherapy may not be a good idea for a cat with poor kidney function.