My pet scan in the beginning of treatment did not reveal any problems but my thyroid did stop working during or after the chemo. I was still sooo tired a year after the chemo and my cholesterol levels shot up. I'm on synthyroid medicine now and it helped with eveything. I do have a friend that had it in her thyroid. That was 3 years ago and she is doing fine. I believe they did radiation. Hope this helps.