The trials in this protocol deals with the effect of pretreatment with rhTSH on radioiodine treatment of thyroid size and function, in patients with nontoxic and toxic nodular goiter. It is an introduction of a novel principle, based on prospective, randomized double blind investigations. Attached to this, we investigate the acute effects of rhTSH on thyroid size (measured by ultrasonography), both in healthy individuals and in patients with nontoxic nodular goiter. Thus, the investigations are divided into 4 categories listed below: