iodine-131

…exceptionally useful radioactive isotope is iodine-131, which has a half-life of eight days. It is employed in medicine to monitor thyroid gland functioning, to treat goitre and thyroid cancer, and to locate tumors of the brain and of the liver. It is also used in investigations to trace the course…

…humans and other animals is iodine-131, an isotope that emits beta and gamma rays and is enriched about 100 times in the thyroid gland through selective accumulation. Because of its relatively short half-life (eight days), iodine-131 is probably not the most hazardous fallout isotope; yet, excessive amounts of radiation from…

…in particular organs: for example, iodine-131 settles in the thyroid gland and can reveal a variety of defects in thyroid functioning. Another isotope, carbon-14, is useful in studying abnormalities of metabolism that underlie diabetes mellitus, gout, anemia, and acromegaly.

Iodine-131 has proved effective in treating hyperthyroidism. Another medically important radioactive isotope is carbon-14, which is used in a breath test to detect the ulcer-causing bacteria Heliobacter pylori.

…radioisotopes are used as tracers, iodine-131, phosphorus-32, and technetium-99m are among the most important. Physicians employ iodine-131 to determine cardiac output, plasma volume, and fat metabolism and particularly to measure the activity of the thyroid gland where this isotope accumulates. Phosphorus-32 is useful in the identification of malignant tumours because…

…radionuclides suitable for metabolic studies, iodine-131 is one of the most widely used. This gamma-ray emitter has a half-life of eight days and concentrates in the thyroid gland, and so provides a measure of thyroid function.