What Is Iodine-131 or I-131?

Cats that have been diagnosed with hyperthyroidism can be treated with radioactive iodine, destroying the overactive parts of the thyroid gland with a high rate of success. Radioactive iodine is administered by our trained and authorized radiology staff subcutaneously. The radioactive iodine will then concentrate in the abnormal thyroid tissue destroying it, allowing the normal thyroid tissue to begin functioning normally.

How is Hyperthyroidism Diagnosed?

The diagnosis of hyperthyroidism requires careful consultation with your veterinarian, who also should check your pet for other medical problems such as heart or kidney disease. Your veterinarian will order a blood test to check thyroid hormone levels and to detect overactivity in the thyroid gland.  

What is the Schedule for the Treatment?

Prior to I-131 treatment, our Internal Medicine specialist will meet with you and your cat. After the evaluation we will schedule the therapy. Typically, your hyperthyroid cat will be admitted on a Monday and the radioiodine treatment will be given that same day. Your pet will stay hospitalized until the end of the week. Most treated animals can go home Friday afternoon, but occasionally a pet will have to remain in the hospital through the weekend so that the levels of radiation in their body has decreased sufficiently for release. While your pet is undergoing therapy, he/she will stay in a special, centrally located, radiotherapy hospital ward and will be cared for by our authorized staff. Our I-131 program is approved by the Nuclear Regulatory Commission and is overseen by both our Radiology and Internal Medicine Departments.

Cats that are hospitalized for I-131 therapy are housed in a special ward. The ward has limited access by our staff to restrict radiation exposure. However, we understand that many cats are very social in nature. Our goal is to make your cat's stay as stress free as possible, the ward has a large window and is located right outside our staff break room. There is continual foot traffic in this area that all of the cats can observe from their enclosures to eliminate some of this isolation . There is also a small fish tank in the ward that the cats have the opportunity to observe throughout their stay. Our staff will call you daily with an update on how your cat is doing.

Guidelines for Home Care after Discharge

Fill and submit our I-131 referral form here

Feline hyperthyroidism is one of the most common diseases of older cats, usually due to enlargement of the thyroid gland. The veterinarians of Central Hospital for Veterinary Medicine have experience in diagnosing and treating this disease, as well as administering the effective radioactive iodine or I-131 treatment option.

Some advantages of I-131 treatment over medical and surgical treatments for feline hyperthyroidism are listed below.

  • No anesthesia is required
  • No daily medication
  • Returns thyroid function to normal usually within one month
  • Cost Effective
  • Does not have harmful side effects
  • Does not destroy healthy tissue
  • Does not damage other tissue or organs, including parathyroid glands