Radioiodine Treatment for Cats
What is radioiodine treatment?
Radioiodine treatment uses a small dose of radioactive iodine (I-131) to destroy overactive thyroid tissue. The radioiodine is administered as an injection under the skin between the shoulder blades, similar to a vaccination. The radioactive iodine is then taken up by the thyroid gland, where it destroys the abnormal tissue. Usually, we do not sedate cats to give the injection.
Why choose radioiodine therapy?
Radioiodine offers a number of important advantages. It does not require surgery or general anaesthesia, and it treats all affected thyroid tissue regardless of location. Cure rates are very high (more than 95%), and most cats do not need further treatment after a single injection.
For many owners, the biggest benefit is simplicity. Once treated, there is usually no need for daily medication or frequent monitoring long term. Some cats may become hypothyroid after radioiodine treatment, when the gland stops producing enough thyroid hormone, and these will have to have lifelong thyroid supplementation, but this is rare.
How effective is it?
Most cats return to normal thyroid function within a few weeks to months after treatment. A small proportion may require a second treatment, particularly in more advanced cases. If a second treatment is needed, this will be administered free.
Before treatment
Before your cat is referred to us, your vets should carry out a detailed assessment to ensure radioiodine is appropriate. This includes blood tests, urine analysis, blood pressure measurement, and sometimes imaging.
This testing is particularly important in older cats, as it allows us to identify any underlying conditions, such as kidney disease, that may influence treatment decisions.
Admission and treatment
On the day of your appointment your cat will be admitted to our dedicated facility and given time to settle.
We will take a blood sample to measure your cat’s thyroid levels on the day of admission. We then calculate the correct dose of radioiodine to administer. The radioiodine injection is then given. This is just like a vaccine and tolerated very well by most cats, but sometimes light sedation is needed.
After treatment, your cat will remain in an isolation ward while radiation levels gradually decrease. During this time, handling and treatment is limited due to safety regulations, but cats are monitored closely and cared for by our experienced team. We take regular measurements of your cat’s radiation levels and once these have dropped significantly then we will contact you to let you know your cat can come home!
Why treatment is important
Without treatment, hyperthyroidism can lead to progressive weight loss, heart disease, high blood pressure, and organ damage. Fortunately, with appropriate treatment, most cats respond very well and can return to a good quality of life.
Helpful Links
International Cat Care – Hyperthyroidism in cats