Helping to alleviate pain in dogs, cats, rabbits, ferrets, and birds

Hopkinton Animal Hospital
1325 Hopkinton Road, Hopkinton NH 03229

Treatment: Understanding Your Cat’s I-131 Journey to Wellness

During your cat’s stay with us they will be monitored by a Canine/Feline ABVP board-certified practitioner during all stages of the I-131 injection process. And since the entire Hopkinton Animal Hospital team is Fear-Free certified, you can rest assured that your pet will be receiving loving care the entire time.

Additionally, to help further ease your cat and make them more comfortable, you can provide the following the day of the injection:

  • A blanket or towel. We will be unable to return it due to the radioactive properties of the treatment
  • Your cat’s favorite food or treats if they do not contain fish or fish oil — these can interfere with the thyroid iodine uptake. Any leftovers will be discarded.


Prior to your cat’s I-131 treatment, your primary veterinarian will need to perform a range of diagnostics and tests to ensure your cat is fully prepared. All pre-treatment must be completed approximately two weeks prior to the I-131 injection date. If your primary veterinarian is unable to have all pre-treatment completed in time, our care team at Hopkinton Family Hospital will be happy to provide all pre-treatment services required and consult with your primary veterinarian. As part of our pre-treatment plan, we will provide a full examination of your cat, consult with your primary care veterinarian and review all necessary health records and tests, such as blood work and x-rays.

Your Cat’s Extended Stay with Us

After the I-131 treatment, and since your cat will be radioactive, they will need to stay with us in a specially designed I-131 treatment suite for approximately five days. This extended stay is required by State and Federal law until their radioactivity levels reduce to a safe level for the general population — this will ensure your safety, theirs and lead to the best positive health outcome for them.

While here, your cat will be comfortable and cared for by one of our I-131 trained staff who will also be acting as a ‘surrogate family member’ to your pet. This staff member has been trained in radiation safety and will be able to be in our I-131 suite with your cat to provide TLC, change bedding as needed, monitor intake of water and food and assess overall behavioral health.

Additionally, during your cat’s extended stay, you will be able to log in and virtually visit your cat through the live streaming video system built into the suite.

Post-Treatment Care

Upon your pet’s departure from Hopkinton Animal Hospital, you will be given detailed instructions on how to ensure both you and your cat stay safe. Your cat will have a very low level of radiation for approximately two more weeks after their stay with us. The amount of radiation is equal to the amount you would receive if you spent at a day at the beach, which means there is minimal risk to you, but these rules are required by State and Federal Radiation laws. For the entire two weeks:

  • Limit (not stopping) contact with your cat for 2 weeks post-treatment.
  • Must stay indoors post-treatment.
  • Wash your hands each time after handling your cat.
  • We recommend that pregnant women not participate in their cat’s care.
  • Children aged under 18 should not touch your cat.

Only after the two weeks period is up can you relax the above guidelines and start to treat your cat as you normally would.

Reference Materials

Please click here to view information about your pet’s i131 treatment.

New Hampshire i-131 at Hopkinton Animal Hospital provides treatment for hyperthyroidism in cats and guinea pigs

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