Advanced Care

Feline Radioactive Thyroid i-131 Treatment

VCA Avondale Cat Hospital offer Feline I-131 Treatment for cats suffering from hyperthyroidism. I-131 treatment has advantages over medical and surgical treatments for feline hyperthyroidism.

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


The I-131 treatment includes a consultation with the doctor, the radioactive iodine injection, a urinalysis, blood pressure, hospitalization and a waste disposal container for home use.

VCA Avondale Cat Hospital was granted an amendment to the release criteria for cats undergoing hyperthyroid treatment from the Bureau of Radiological Health, a division of the Iowa Department of Health. Based on the research on the actual exposure rates from all cats treated in 2003 that was conducted by the Iowa State University's College of Veterinary Medicine and VCA Avondale Cat Hospital, the criteria has been changed to the following:

  • Maximum exposure rate of 5.0 mR/hour at a distance of one foot from the patient
  • 3-day minimum stay post injection (most patients will be released 3-5 days post injection), and
  • Owners are advised not to have close contact with the patient for two weeks following release


These release criteria are based in the requirement that the dose to any member of the general public must not exceed 100.0 mR in one year. Papers containing the research results will be published and presented to the North Central Chapter of the Health Physics Society, the National Health Physics Society and the American College of Veterinary Radiology.