hyperthyroidism cats

Feline Radioactive Iodine Treatment

Give your cat the best care with our dedicated radioactive iodine unit at Cat Specialist Services in Brisbane. 

What is Hyperthyroidism in Cats? 

Hyperthyroidism is an endocrine disorder of the thyroid gland and is characterized by the overproduction of thyroid hormones (thyroxine). This excess hormone production may then have effects on other areas of your cat’s health. Hyperthyroidism is one of the most common health issues affecting cats occurring in an estimated 10% of felines aged 10 and over and, if left untreated, can lead to serious health issues such as heart problems, kidney disease, and weight loss. 

However, with the right treatment approach, hyperthyroidism can be effectively managed and controlled. 

Symptoms of Hyperthyroidism in Cats 

Symptoms shown by cats with hyperthyroidism often develop gradually and include: 

  • Weight loss (despite a good appetite) 

  • Increased vocalisation 

  • Behavioural changes (e.g. increased agitation) 

  • Vomiting 

Hyperthyroidism Treatment for Cats 

There are a number of hyperthyroid treatment options available for your cat, including medications to suppress the thyroid hormone production, surgical removal of the thyroid tumour and radioactive iodine (I131- therapy) to destroy the thyroid tumour cells responsible for the hormone production. Each treatment option has both pros and cons to consider when choosing the right treatment for your pet. 

Radioactive Iodine Treatment 

Radioactive iodine is considered the best treatment for most cats of any age because it is simple, effective and safe. If hyperthyroidism is left untreated, symptoms can become severe and the disease can be fatal. Additionally, there is evidence to suggest that in cats that receive long term medical management (e.g. tablets) the benign tumour (thyroid adenoma) can progress to a malignant and more aggressive tumour type (thyroid carcinoma). 

At Cat Specialist Services, we offer a specialised facility for the treatment of hyperthyroid cats using radioactive iodine (I-131). This highly effective treatment involves a single capsule given by mouth and is generally well tolerated by cats, with a high success rate. Most cats will achieve normal thyroid hormone levels within a few weeks of treatment. 

Cat Specialist Services Radio Active Iodine
Radioactive Iodine Therapy

How Does the Radioactive Iodine Treatment Process Work? 

The process of administering I-131 to cats begins with a thorough evaluation by one of our veterinarians, including physical examination and assessment of blood work, and possibly other diagnostic tests to determine the severity of the hyperthyroidism and to rule out any other underlying health conditions. Once a treatment plan has been established, the cat will be admitted to our facility for treatment. 

After treatment cats will need to remain in isolation to allow the radioactive iodine to decay. This is a standard safety precaution by Queensland Health to protect both the cat and the people caring for them. This is typically for 5-7 days depending on the dosage of radioactive iodine that is given. During this time, cats have their own unit with plenty of space to explore, soft bedding, ramps, natural sunlight, and a lovely garden view. Our staff will monitor the cat's condition closely and provide any necessary supportive care, including pain management and nutritional support. 

The radioactive iodine facility at Cat Specialist Services is designed specifically to provide cats with access to natural sunlight, garden views, and environmental enrichment during hospitalisation (we even have cat TV!). This is important for their overall well-being while they are away from home. In addition to providing a comfortable and stress-free environment for cats, our facility has state-of-the-art equipment and is staffed by a team of experienced and compassionate specialist feline veterinarians and support staff. 

Ongoing Care for your Cat 

When the isolation period is over, cats can go home with their owners. Cats need to be kept indoors for a further 2 weeks. If this is difficult to do at home, then cats can move from the radioactive iodine suite into our medical boarding suites. These suites also have natural sunlight, and plenty of sleeping areas, and cats can also spend time in one of three “play rooms” - we have a Harry Potter, Star Wars, or Lord of the Rings playroom! 

Follow-up care will be important to ensure that the cat's thyroid hormone levels remain normal and to monitor for any potential side effects. Our team will work with you to develop a plan for ongoing management and care of your cat. 

How Do I Book Radioactive Iodine Treatment for My Cat? 

Register your interest and we will contact you to organize your cat's treatment. 




Address 1-15 Lexington Rd,
Underwood, QLD, AU, 4119

PhonePh: 1300 228 377

Hours Monday-Friday: 8 am-6 pm
Saturday/Sunday - Closed

Veterinary Specialist Services