Lyn

You are right that the doctors should do a TSH test BEFORE treatment and the guidelines suggest that but in practice, many many posters here did not get such the TSH test before starting radiation. Since most doctors working now went to medical school back in the 20th century instead of this century, they falsely assume that giving their patients a TSH test AFTER treatment will identify if there is a thyroid issue. But all a test afterwards does is tell them whether or not you are in a super wide range of "normal" which is worthless information to you as an individual. The better doctors just go ahead and prescribe thyroid meds if the patient has symptoms but some are overly cautious or still relying on last century's information. Bottom line: you need and want your post treatment TSH level to be the same as it was before your treatment. If you do not know your actual TSH level number before TX, then it's only a guess .
Charm