Radioiodine

Part of speech: noun

Definitions

1. A radioactive form of the element iodine that is used in medical diagnosis and in treating conditions such as an overactive thyroid
2. An unstable, radiating variant of iodine employed in medical imaging and in therapy for thyroid disorders
3. A radioactive isotope of the chemical element iodine, applied in clinical tests and in treatments targeting the thyroid gland

Etymology: Radioiodine is a compound built from two parts. The first, "radio-", comes from Latin "radius", meaning ray or spoke, and in English it came to signal radiation or radioactivity. The second, "iodine", was named in 1811 by the French chemist Joseph Louis Gay-Lussac, who derived it from Greek "iodes", violet-coloured, after the violet vapour the element gives off when heated. The word "iodine" itself carries that Greek colour in its ending: "ioeides" in Greek is built from "ion", violet, and "-eides", resembling, and the Greek "ion" traces back to an ancient root shared with the flower name "violet". Because iodine was discovered as a nonradioactive element, the "radio-" prefix had to be attached later, once scientists began making radioactive forms of the element for use in medicine and research.