Iodine-131 bioaccumulation in regions where radioiodine has sufficiently contaminatated the environment. Iodine-131 is used for unsealed source radiotherapy in nuclear medicine to treat several conditions. It can also be detected by gamma cameras for diagnostic imaging, however it is rarely administered for diagnostic purposes only, imaging will normally be done following a therapeutic dose. Use of the I as iodide salt exploits the mechanism of absorption of iodine by the normal cells of the thyroid gland. Major uses of I include the treatment of thyrotoxicosis (hyperthyroidism) due to Graves' disease, and sometimes hyperactive thyroid nodules (abnormally active thyroid tissue that is
Absent adrenal gland Absent adrenal gland Absent adrenal gland is a rare condition where the adrenal gland is absent at birth. It should not be confused with adrenal insufficiency or congenital adrenal hyperplasia, where the gland is present but may not be functioning adequately. Due to the absence of adrenal cortex, the condition causes extreme symptoms of adrenal insufficiency at birth due to very low levels of aldosterone and cortisol. The adrenal medulla can be normally present, poorly formed, or absent, however even so the effects of circulatory catecholamine deficiency are generally mild (due to sympathetic nervous system compensation), except in episodes of