Client Information Summary for Radioactive Iodine Therapy

Hyperthyroidism is a progressive condition commonly affecting older cats caused by excess production of thyroid hormones from the thyroid gland. The excess thyroid hormone is the result of a tumor on the thyroid gland - the vast majority of these tumors are benign. Clinical signs are characterized by an increase in metabolic rate that can start gradually but becomes more severe over time. You may notice your cat voraciously hungry but unable to keep weight on, experiencing increased vocalizations/hyperactivity, vomiting, diarrhea, and a poor hair coat.

I-131 is radioactive isotope and when injected into the body it is taken up by the thyroid gland. The normal thyroid tissue is relatively “protected” from the effects of the radioiodine because the I-131 is preferentially taken up by abnormal, hyperfunctional tissue. Once the abnormal nodule is destroyed, the remainder of the thyroid tissue performs normally again. The success rate of I-131 treatment is approximately 96%. Occasionally a cat will need a second treatment 3-6 month later if not cured, or require a thyroid hormone supplement if the thyroid is too low.

Within the month before radioactive iodine therapy, your cat will need to be screened for any concurrent disease processes that may affect their response to treatment. These tests may be completed with your referring veterinarian or with us at Weymouth Landing Cat Clinic. We require that your cat has updated labwork and radiographs within this time frame. A complete blood cell count (CBC) will assess for anemia, autoimmune diseases, and signs of infection/inflammation. A chemistry panel will assess your cat’s kidney function, liver function, electrolytes, and blood sugar. A T4 will confirm your cat has hyperthyroidism and their current thyroid value. A urinalysis will help assess for kidney function and any presence of crystals, a urinary tract infection, or other bladder issues. A blood pressure will assess for hypertension. Chest x-rays will look at your cat’s heart size and assess for any masses.

Your cat will be required to be up to date on their rabies vaccine to be admitted into the program and be up to date on their flea preventative during their stay. It is recommended, if your cat has been deemed healthy enough by your veterinarian, that they are up to date on their feline distemper vaccine as well but this will not be required for treatment.

It is recommended that your cat has been initially treated for their hyperthyroidism with either Methimazole or Hill’s y/d diet. This is so that your veterinarian can assess how their kidneys, heart, and other organs have responded to thyroid treatment. Thyroid disease can mask how advanced kidney disease has progressed in a patient and if your cat has advanced kidney disease, it might not make them a great candidate for radioactive iodine therapy. If your cat has been treated for hyperthyroidism, they will need to discontinue that treatment prior to radioactive iodine therapy. They would need to stop Methimazole one week prior to therapy or stop their y/d diet two weeks prior to therapy.

Our nuclear liaison will review referral documents to ensure all requirements have been completed or assist you in scheduling an appointment to achieve the requirements for therapy. A deposit will need to be collected prior to Dr. Laporte doing a final review of the records.

The cost of radioactive iodine therapy is $2400. A non-refundable deposit of $1200 will be made at the time of booking and the remainder will be collected at admission. This fee does not include the required diagnostics for your cat to be admitted to the program. Should your cat’s records be reviewed and deemed to be missing required diagnostics, they will need to be done within the month before therapy at your veterinarian’s office or at a consult appointment with Dr. Laporte at WLCC. We will provide you with an estimate for the required diagnostics at the consult appointment.

We will not be able to house your cat for the full two weeks of post therapy restrictions once your cat is able to be discharged. You must be able to provide the safe and appropriate care at your home following your cat’s discharge. If you are not able to pick up your cat on the Friday that they are deemed safe to be released from the radioactive iodine suite, you will incur an additional fee for them staying over the weekend.

Following radioactive iodine therapy, your cat should have their CBC/Chem/T4 lab work rechecked both one month and three months post discharge. This is to assess how your cat’s thyroid and kidneys have responded to treatment and to ensure no (rare) additional supplementation or second treatment is required. These rechecks are not included in the cost of therapy.

If your cat has met all the required diagnostics prior to the day of therapy, we will first meet you and your cat on admission day. We will schedule an appointment on the Monday morning of drop off with Dr. Laporte and the veterinary technician. If your cat has not met all the requirements and you would like to have these diagnostics done at Weymouth Landing Cat Clinic, our liaison will schedule you an appointment prior to the therapy date for a consult.

At admission, your cat will receive their subcutaneous injection of radioactive iodine (I-131) and will be settled into a condo in our radioactive iodine suite. They will remain at our hospital for a minimum of 96 hours. During this time, they will be boarding as their radiation levels decrease and until they are at a safe level of radiation for release. Your cat will not be able to be released earlier than four days following their injection under any circumstances. Our program is designed for your cat to be admitted on Monday morning and discharged on Friday. Occasionally we will have a cat that has not met the safe levels of radiation exposure for release and will need to remain in our care over the weekend. Your cat will be scanned for radiation levels on Thursday and if they are at a safe limit, we will call you to set up a discharge for the following day. If they are not at releasable levels on Thursday, we will scan them again Friday morning. At this time, we will likely call you to arrange a discharge time later in the day or, less likely, inform you that your cat is still too radioactive and must stay the weekend. If your cat must stay the weekend because they are not at releasable radiation levels, there will be no additional fee incurred.

Only authorized personnel are allowed in the “hot” room for a limited amount of time. As a result, there is no pet parent visitation allowed during your cat’s therapy. We do have the ability to email photos of your cat during their stay upon request. You may bring comfort items such as a bed or blanket but please note that these items will not be returned to you. By law, the items are required to be stored for 90 days and discarded after therapy and will not be returned to you. You may call the hospital at 781-337-0400 to check in on your cat at any time during their stay. We do not provide overnight care at our hospital so please call during business hours to check in on your cat.

While in the radioactive iodine suite, your cat will be cared for at least twice daily. Our trained staff will provide them a breakfast and dinner meal, refresh their water, and clean their litterboxes. We will not be able to pet or cuddle your cat during this time for the safety of the staff. The suite is in a small quiet room and we will have calming cat music playing for them during their stay. We will also have a soothing cat pheromone spray called Feliway present in the room and can offer cat nip to alleviate anxieties. Any medications that your cat is on must be able to be mixed into their food. We will not be able to handle your cat regularly to administered daily medications by any other method. You will be required to bring their normal food and their medications that will last them through their stay. Should your cat run out of food, we are able to provide Fancy Feast canned food or a gentle GI diet. We will keep a close eye on your cat’s appetite and litterbox habits. If we have any concerns, our doctors will be alerted and we will address the issue to the best of our abilities while your cat is radioactive. It is not uncommon for some cats to need an appetite stimulant or anti-anxiety medication during their time away from home. Should this situation arise, we will inform you and these medications may result in additional fees if needed.

Due to the human health risk associated with radioactive iodine therapy, on the rare chance that your cat goes into respiratory or cardiac arrest, we will not be able to perform CPR and your cat will not be able to be resuscitated. In the highly unlikely event that your cat perishes during therapy, their remains will need to remain at Weymouth Landing Cat Clinic for 90 days before they are able to be released to your family.

There are strict regulations that MUST be followed once your cat is released from radioactive iodine therapy. If you and your family are not able to meet these requirements, your cat is not a candidate for this treatment and you will be denied. Our hospital does not have the facilities to keep your cat for the entire two-week period that the restrictions are in place and you must be able to adhere to these rules at your home.

Your cat will have residual radioactivity shedding primarily in their feces and urine once they are discharged. The radioactivity may also shed in their sweat and saliva. The following precautions must be taken for the 2-week period after discharge to ensure safety for you and your family.

1. It is required that you have a plastic carrier with a pee pad or towel lining the bottom of the carrier. This is so that if your cat urinates, defecates, or vomits in the carrier, you can safely remove and hold the waste as directed below. Fabric and cardboard carriers will not be accepted.

2. Petting, holding, and co-sleeping are restricted for 2 weeks after release. You are only allowed to pet your cat for 5 minutes at a time (up to 20 minutes per day) and hold your cat 1 minute at a time (up to 5 minutes per day) during this time.

3. Children under the age of 18 and pregnant women are not allowed to have any contact with your cat whatsoever for 2 weeks after treatment.

4. To the best of your ability, your cat should be confined to a single room for 2 weeks and should be isolated at night, out of your bedroom. Do not let your cat outside.

5. Wash your hands after any interaction with your cat.

6. Your cat should not be allowed near any food preparation areas. Should your cat gain access to these areas, you must wash the area well immediately and isolate the cleaning supplies.

7. Kitty litter and contaminated items from the 2-week period should be stored for 90 days (3 months) in the provided 5-gallon bucket. You must wear gloves to handle any waste.
a. If your cat vomits or urinates/defecates outside of the litterbox, any cleaning supplies must also be held for this time.
b. If you dispose of any contaminated litter in your trash can during the 2-week restriction period, radiation monitors at the trash disposal facility will detect it. This will result in costly expenditures of labor for cities and towns necessitated by isolating and analyzing the radioactive materials. The radioactive trash will be traced back to you and will result in substantial financial liability.

8. If your cat needs medical care during the 2 weeks after discharge, they should be brought back to WLCC. If your kitty goes elsewhere, you need to inform the veterinary staff of your cat’s recent treatment for radioactive iodine.

Failure to comply with the restrictions will result in negative impacts on your health and safety and may result in costly fines from your town. Each waste management facility has a Geiger counter that scans for radioactivity and it is easily traceable back to your home. Weymouth Landing Cat Clinic is not responsible for any fines incurred for not adhering to the restrictions.

It is recommended that you prepare for your cat’s return home by setting up their isolation room. Please have a plastic lined litterbox available in their space as well as their food and water bowls. These items, along with their bedding, should be able to be held separately in a lightly trafficked area for 90 days after the two-week restrictive time is complete. You will also need to have rubber or disposable gloves available for cleaning and interacting with your cat. We will provide you with a 5-gallon bucket with waste instructions upon discharge. Please line this bucket with a plastic bag and follow the instructions for waste holding and disposable.