Cindy, they usually cannot leave the lobe, the thyroid is a very vascular organ, you cannot chop half off without a great deal of blood loss. Sometimes if your nodule is in the lowest pole they can take only half, but most won't do it. There is also the question of the Recurrent Laryngeal Nerves running directly through the thyroid lobes, they have to be very careful...it is a delicate surgery. Some people with half a thyroid don't have to be medicated, about 40%, I think I read.