Iodine deficiency
![Sequence of 123-iodide human scintiscans after an intravenous injection, (from left) after 30 minutes, 20 hours, and 48 hours. A high and rapid concentration of radio-iodide is evident in the periencephalic and cerebrospinal fluid (left), salivary glands, oral mucosa and the stomach. In the thyroid gland, I-concentration is more progressive, also in the reservoir (from 1% after 30 minutes, to 5.8 % after 48 hours, of the total injected dose.[18]](/uploads/202501/20/Sequence_of_123-iodide_total_body_human_scintiscans1853.jpg)

Iodine deficiency is a lack of the trace element iodine. It may result in goiter (so-called endemic goiter), as well as cretinism, which results in developmental delays and other health problems. Iodine deficiency is an important public health issue as it is a preventable cause of intellectual disability.