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19203 Aurora Avenue North
Shoreline, WA 98133

fax 206-546-5758


5506 Pacific Avenue
Tacoma, WA 98408

fax 253-471-9222


By appointment only


Treating Hyperthyroidism In Cats Since 1992 


Our History

"After 15 years practicing general feline medicine and seeing numerous hyperthyroid cats, my goal became to provide my patients with the safest and most reliable therapy for hyperthyroidism. With very few exceptions that therapy is, radioiodine (131I therapy). In 1992, after completing training at the University of Washington and the University of Saskatchewan, I established Feline Hyperthyroid Treatment Center, P.S..The University of Saskatchewan, like most nuclear medicine facilities, gave a "fixed dose" (4 mci.) to all cats. Depending upon the facility the "fixed dose" will vary from 3-6 mci. I use a "variable dose" approach, which means I try to tailor a cats' dose to individual disease. My dose range is from 1-8 mci. The average dose used in 2010 was about 3.0 mci. Kidney function, heart disease, thyroid hormone levels (T4), and thyroid size are primary considerations in determining an individual cats dosage. If I don't eliminate the disease within the first 3 months (about 5%) I typically retreat at no charge, the rare exception being cats with thyroid carcinoma.  131I is typically the safest, best and ultimately least costly lifetime therapy for hyperthyroidism in cats."

                     Dennis Wackerbarth, Founder and Medical Director


 Radioiodine treatments to treat hyperthyroidism in cats are offered in two Puget Sound locations; in Shoreline just 15 miles north of downtown Seattle and in Tacoma in the South Sound area. After reading  our FAQ section please call us if you have further questions or wish to schedule an appointment. 

Please contact our Shoreline location for scheduling.  (206) 546-1243.  You may also email us at



Our Doctors

Faythe Vaughan, D.V.M.

Dr. Vaughan started working with Dr. Wackerbarth in Feline Hyperthyroid Treatment Center in 2002 and today devotes most of her clinical time to treating hyperthyroid patients. Dr. Vaughan graduated from Auburn School of Veterinary Medicine in 1985. After completing an intership at Washington State University in 1987, she moved to Seattle, and after working in a mixed  practice for two years, she  joined the Cats Exclusive medical team. Over the past 25 years, she has honed her skills in feline medicine and surgery, developing a particular affinity for her senior patients and their complex medical scenarios. In March 2011, she was recognized as a top Seattle veterinarian (as selected by her peers) in  Seattle Metropolitan magazine. She continues her quest to bring the most current concepts in feline medicine to her patients by participating in considerable continuing education every year.

Dennis Wackerbarth, D.V.M.

Dr. Wackerbarth is the medical director and founder of both Feline Hyperthyroid Treatment Center and Cats Exclusive Veterinary Center. A graduate of Washington State University College of Veterinary Medicine in 1977, Dr. Wackerbarth is well known for his visionary contributions to feline medicine in the Northwest. He established Cats Exclusive Veterinary Center in 1981, becoming one of the first practices in the United States devoted to feline medicine. In the early 1980's he also co-founded the Seattle King County Medical Association's continuring education association for veterinarians. In 1992 he began administering radioiodine treatments for feline hyperthyroidism after extensive training at the University of Washington and the University of Saskatchewan in Canada. He was the first veterinarian in the Northwest to offer radioiodine therapy for cats. Dr. Wackerbarth serves as the medical director for both the Shoreline and Tacoma locations and is a consultant to hundreds of veterinarians in the region.