Iodine Therapy (I131)
What is Radioactive Iodine? (Also known as I-131 Treatment)
I131 is a radioactive form of Iodine. It emits two types of radiation: Beta Particles and Gamma Particles. Beta particles are the reason it is effective for hyperthyroidism treatment. It is generally a very safe and effective treatment for cats, and has the advantage of being CURATIVE in approximately 95% of patients.
How does I-131 Treatment Work?
I131 can only be administered in specially licensed facilities (hence why your cat may have been referred to us by your usual veterinary clinic). Here at McMaster and Heap Veterinary Practice the Radioactive Iodine is administered to your cat as a single “one off” subcutaneous injection (an injection under the skin) on the afternoon of admission to the clinic. This is completed only by a veterinarian. The Radioactive Iodine is then quickly absorbed into the cats blood stream and makes its way to the ACTIVE (abnormal) thyroid tissues in your cats body. The Radioactive material is NOT taken up in any other body tissues as the thyroid is the only area in the body to utilize iodine. Therefore, the treatment results in a selective accumulation of radioactive material in the abnormal tissues only. The radiation destroys the affected “abnormal” tissue, but does not damage the surrounding tissue or parathyroid glands. This process starts to take place within approximately the first 24hrs or so once the treatment has been administered.
What happens during boarding, after the treatment has been administered?
After the Radioactive iodine has been administered, the patient is moved straight to our special isolation boarding facility on site, where they will be well cared for by our qualified and trained nursing and veterinary staff for the next 7 days. Each patient has their own large cage (bedding, bowls and food supplied) and there are large windows in the room for natural light, allowing the cats to happily see outside.
During this isolation time patients are temporally radioactive. The large majority of excess radioactive material is excreted by the patient in the first 3 days following treatment – mainly in their urine/faeces and also small amounts in saliva. These stools and urine emit Beta particles which could become a hazard to a person if unknowingly ingested or inhaled. Because of this reason, only authorised staff can care for the patients and owners are not permitted to visit their cat during the 7-day period post treatment. For the same reason, any bedding/toys etc. brought in for the cat’s stay will NOT be returned to the owner on discharge & will be discarded.
Blood testing following treatment
Your cat MUST have a repeat blood test in 1 month and 4 months following the date of treatment. This is required to ensure normal thyroid levels are now being maintained and kidney functions are stable. If you have been referred to us for treatment by another vet clinic, please arrange this blood test and any following general health checks with them over the phone, at your convenience.
For further information on Iodine Therapy (I131) please click here to go to our client information sheet.
