Isotopes of iodine and non-radioactive materials can be described as "cold." There are instances in which cold iodide is administered to people in order to prevent the uptake of hot iodide by the thyroid gland. For example, blockade of thyroid iodine uptake with potassium iodide is used in nuclear medicine scintigraphy and therapy with some radioiodinated compounds that are not targeted to the thyroid, such as iobenguane (MIBG), which used to image or treat neural tissue tumors, or iodinated fibrinogen, which is used in fibrinogen scans to investigate clotting. These compounds contain iodine, but not in the iodide form. However, since they may
Tincture of iodine by Grossich. He claimed in 1915 that Grossich had been using a liquid akin to Liquor Iodi Fortis, and that it was he, Stretton, who had introduced the method using Tincture of Iodine BP which came to be used across the world. USP Tincture of Iodine is defined in the U.S. National Formulary (NF) as containing in each 100 mL, 1.8 to 2.2 grams of elemental iodine, and 2.1 to 2.6 grams of sodium iodide. Alcohol is 50 mL and the balance is purified water. This "2% free iodine" solution provides about one mg of free iodine per drop. USP