Research overview: radioactive iodine therapy for feline hyperthyroidism

Radioactive iodine (I-131) therapy is widely regarded as the gold-standard treatment for feline hyperthyroidism because it selectively destroys overactive thyroid tissue while sparing normal tissue, often achieving cure with a single subcutaneous injection. The radioiodine concentrates in hyperfunctioning cells, and most treated cats become euthyroid without ongoing medication. The approach requires specialized licensed facilities and a hospitalization period for radiation safety. This overview compiles the treatment literature rather than one source, describing why selective uptake makes radioiodine both effective and sparing of healthy tissue, the practical requirements and brief isolation involved, and how unmasking of underlying kidney disease after treatment is monitored. It matters because radioiodine offers a definitive cure for a common disease, avoiding lifelong medication or surgery in most cats.