Doc, I have had hyperthyroid for almost 3 years, and I was able to use ATD(Methimazole) to control it. But my doctor mentioned that I should not take ATD for long term (more than 2 or 3 years), and suggested RAI treatment. but he did not give me the details of what kind of problems the long term ATD can cause. Can you tell me more about this ? Also, I read from internet, says U.S. doctors choose RAI more, but European doctors prefer ATD, Why such difference ?? Thanks.