Radioiodine Imaging and Treatment in Thyroid Disorders.

Thyroid hormones T3 and T4 are crucial for development and differentiation of various cells in the body. They are also essential for regulating metabolism in nearly all tissues. Iodine is an integral element in the synthesis of thyroid hormone and is actively transported into the thyroid by a Na+/I- symporter. The thyroid can take up radioactive iodine just like it would take iodine and hence can be used to evaluate and treat several thyroid diseases. Radioactive iodine is one of the first radioisotopes to be used in medicine.