Feline I-131 Therapy

Feline Radioactive Iodine (I-131) Therapy at ISU Lloyd Veterinary Medical Center

What to Expect:

Before Treatment

Before radioiodine (I-131) therapy for feline hyperthyroidism at ISU, your cat will undergo an initial screening appointment. During this appointment, we'll assess your cat's overall health through a physical exam, basic lab tests, blood pressure measurement, and possibly an echocardiogram. Additional tests may be recommended based on your cat's health. Initial appointments are scheduled on Mondays or Tuesdays.

Can Cats Be on Methimazole Before Referral?

Your cat should continue its hyperthyroid treatment (methimazole or Y/D diet) until its screening appointment. However, cats must stop methimazole at least 7 days before being seen for its treatment appointment (preferably 10-14 days before). Cats on Hill’s Y/D food should transition back to their regular diet at least a week before treatment.

What Comes Next?

After the screening, your cat will return for thyroid scintigraphy and I-131 administration. Scans are usually done on Wednesdays, followed by treatment the following day. I-131 is given as a single, subcutaneous injection.

Hospital Stay

Following treatment, cats typically stay in the hospital for 4-5 days, usually discharged the following Monday. We'll update you daily on your pet's health, but visits are not allowed during this time. Toys or blankets cannot be brought into radiation isolation.

Discharge Instructions

Before discharge, you'll receive detailed instructions and a waste receptacle for handling your cat’s waste. Cats must be transported in a carrier and handled with latex gloves. During the ride home, place the carrier on the back floorboard or seat—avoiding direct contact with the pet.

Post-Treatment Care

At home, minimize contact with your cat, especially in the first two weeks. Use latex gloves when handling the cat or waste for six weeks, and follow special waste storage procedures.

Cost: The estimated cost for complete I-131 workup and therapy ranges from $3,000 to $3,500.

Follow-Up: Recheck evaluations with your referring DVM are recommended at 6 weeks and 3 months post-discharge.

For more information or questions, please contact ISU-VMC at 515-294-4900.