ABSTRACT
Radioactive iodine isotopes are useful for diagnosing thyroid disorders such as hyperthyroidism, hypothyroidism, and thyroid cancer by determining the size, shape, and activity of the thyroid gland. Radioactive iodine should be used during lactation as it is secreted into the breast milk and may damage the infant thyroid and increase the risk of thyroidal cancer developing in later life. The combination of low serum T4, low plasma inorganic iodide, high thyroidal uptake of radioactive iodine, and decreased urinary excretion of iodine are characteristic of iodine deficiency. Measurements of iodine status in the late 1960s and early 1970s indicated that iodine deficiency was no longer a public health problem in the United States. Iodine is an essential dietary element which may be added to table salt and dietary supplements to prevent iodine deficiency in humans and to animal feed and salt licks to prevent iodine deficiency in animals.
