radium


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radium

 [ra´de-um]
a chemical element, atomic number 88, atomic weight, 226, symbol Ra. (See Appendix 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 radiation therapy for malignant diseases, particularly those that are readily accessible, for example, tumors of the cervix uteri, mouth, or tongue. 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. Radium rays have been used in the treatment of lupus erythematosus, eczema, psoriasis, xanthoma, mycosis fungoides, and other skin diseases; for the removal of papillomas, granulomas, and nevi; for palliative treatment in carcinoma and sarcoma; and in myelogenous and lymphatic leukemia.

ra·di·um (Ra),

(rā'dē-ŭm),
A metallic element, atomic no. 88, extracted in very minute quantities from pitchblende; 226Ra, its longest-lived isotope, is produced as an intermediate in the uranium series by the emission of an α particle from thorium-230 (ionium); 226Ra emits α particles and gamma rays with a half-life of 1,599 years breaking down to 222Rn; chemically, it is an alkaline earth metal with properties similar to those of barium. Its therapeutic action is similar to that of x-rays, since the α emission is filtered out.
[L. radius, ray]

radium

(rā′dē-əm)
n. Symbol Ra
A rare, brilliant white, luminescent, highly radioactive metallic element found in very small amounts in uranium ores, having more than 40 isotopes and isomers with mass numbers between 201 and 234, of which Ra-226 with a half-life of 1,600 years is the most common. It is used as a neutron source for some research purposes and was formerly widely used in cancer radiotherapy and as a constituent of luminescent paints. Atomic number 88; melting point 696°C; boiling point 1,737°C; specific gravity 5; valence 2. See Periodic Table.

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

ra·di·um

(rā'dē-ŭm)
A metallic element, atomic no. 88, extracted in minute quantities from pitchblende; an alkaline earth metal with properties similar to those of barium. Its therapeutic action is similar to that of x-rays.
[L. radius, ray]

radium

A naturally radioactive element with a half-life of 1620 years which decays into the radioactive gas radon. Radium was once widely used in RADIOTHERAPY but has now been largely replaced by caesium 137 and other radionuclides.

ra·di·um

(Ra) (rā'dē-ŭm)
A metallic element, extracted in minute quantities from pitchblende; properties similar to those of barium with therapeutic action similar to that of x-rays.
[L. radius, ray]
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