Radioiodine therapy (I-131) for feline hyperthyroidism provides definitive cure with excellent welfare outcomes, though hospitalization requirements present temporary welfare considerations.
I-131 welfare evaluation must balance the temporary welfare cost of isolation hospitalization against the significant long-term welfare benefit of permanent cure. Hyperthyroid cats experience chronic weight loss, muscle wasting, hypertension, cardiac changes, and secondary kidney stress — conditions that cause ongoing welfare harm for the duration of untreated disease. Compared to lifelong twice-daily medication compliance and periodic monitoring, I-131 delivers superior welfare through cure rather than ongoing management. The hospitalization welfare impact can be substantially reduced by facilities providing enriched isolation with human interaction during the post-treatment period.