Actually, NaI-131 treatments are very common in cats, because there is a high incidence of hyperthyroidism. The NaI-131 cures it and the cat is normal afterwards. Carol Marcus At 05:06 PM 3/24/2008, Clayton Bradt wrote: >On the other hand, anyone stupid >enough to pay for I-131 treatment for >their cat should probably be >monitored closely.