Hi Alf,
Although i haven't had it yet i maybe having it in August or September.
I was diagnosed with an over-active thyroid six months ago and that is one of the options.
Ma father and my sister have both had the Iodine treatment, it seems hard to get it spot on apparently and it may go under-active and in their case they now have to take Thyroxine (Tablet) every day.
My father had his done about 40years ago and he is still going strong.
So, yes it does work even though it may mean taking tablets for the rest of ones life.