radium /ra·di·um/ (ra´de-um) a radioactive element, at. no. 88, symbol Ra; it has a half-life of 1622 years, emitting alpha, beta, and gamma radiation. It decays to radon.
radium (Ra)
radium (Ra) (rā´dē
m),
radium
ra·di·um (r  d - m)n. Symbol Ra A luminescent, highly radioactive metallic element found in minute amounts in uranium ores, used as a neutron source for some research purposes, and formerly used in cancer radiotherapy; its most stable isotope is Ra 226 with a half-life of 1,622 years. Atomic number 88. |
radium (Ra)
[rā′dē·əm]
Etymology: L, radius, ray
a radioactive metallic element of the alkaline earth group. Its atomic number is 88. Four radium isotopes occur naturally and have different atomic masses: 223, 224, 226, and 228. The isotope with atomic mass 226 is the most abundant. It is formed by the disintegration of uranium 238, has a half-life of 1620 years, and decays by alpha emission to form radon 222. Radium occurs in the uranium minerals carnotite and pitchblende, which contain about 3 × 10-7 g of radium per g of uranium. Radium salts have been used extensively as radiation sources in the treatment of cancer but are gradually being replaced in such therapy by cobalt and cesium.
radium (Ra) (rā´dē
m),n a radioactive metallic element of the alkaline earth groups. Its atomic number is 88. Four radium isotopes occur naturally and have different atomic weights: 223, 224, 226, and 228.
radium emanation,
n radon. An element, used in radiotherapy, produced when radium disintegrates.
radium
a chemical element, atomic number 88, atomic weight, 226, symbol Ra. See Table 6. Radium is highly radioactive and is found in uranium minerals. Radium-226 has a half-life of 1622 years. It and its short-lived decay products emit alpha particles, beta particles and gamma rays. One of the decay products, radon-222, is a radioactive gas. In clinical use, radium is contained in a metal container that stops alpha and beta particles and traps radon.
Radium is used in the treatment of malignant diseases, particularly those that are readily accessible, for example, tumors of the eye. In the form of needles or pellets, it can be inserted in the tumorous tissue (interstitial implantation) and left in place until its rays penetrate and destroy malignant cells. It can also be used in the form of plaques applied to the diseased tissue. Large amounts of radium are used as a source of gamma rays, which are capable of deep penetration of matter. See also radiotherapy.
radium
A radioactive metallic element–atomic number 88, atomic weight 226.025, which is an intermediate in the uranium decay series, produced when an α particle is emitted from 230Th
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