\ɹˈe͡ɪdi͡əm], \ɹˈeɪdiəm], \ɹ_ˈeɪ_d_iə_m]\
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Radium. A radioactive element of the alkaline earth series of metals. It has the atomic symbol Ra, atomic number 88, and atomic weight 226. Radium is the product of the disintegration of uranium and is present in pitchblende and all ores containing uranium. It is used clinically as a source of beta and gamma-rays in radiotherapy, particularly BRACHYTHERAPY.
By DataStellar Co., Ltd
By William Dodge Lewis, Edgar Arthur Singer
A metallic element, symbol Ra, atomic weight 226.4, extracted in very minute quantities from pitchblende; it is nonexistent, so far as known, in a free state. Radium salts possess the property of radioactivity to a degree greater than that of any other known substance, 100,000 times more than uranium; it is fluorescent and imparts this quality to other substances, causes gases to become conductors of electricity, discharges electrified bodies, and affects a photographic plate through opaque substances. It gives forth three kinds of rays, known as alpha (a), beta (b), and gamma (v) (see under ray), and also a radioactive gas or emanation (niton). Its therapeutic action is similar to that of the x-rays, being employed in the treatment of lupus and other skin diseases, and of carcinoma and sarcoma. It causes extensive "burns" of the skin when applied too long and without a proper shield. The many known disintegration products of radium emanation are called respectively radium A, B, C1, C2, D (radiolead), E1, E2, and F (polonium, or radiotellurium).
By Stedman, Thomas Lathrop
By James Champlin Fernald
By Nuttall, P.Austin.
A substance contained in minute quantities in pitchblende and in other minerals, capable of emitting rays or particles (a, b, y,) due to the disintegration of the molecule, which perhaps have therapeutic properties. The metal has properties which resemble barium. Atomic weight, 225. Symbol, Ra. Used only in the form of its salts, the emanations of which are employed in the treatment of lupus, epithelioma, and other affections.
By Smith Ely Jelliffe