radioactive isotope


radioactive isotope

also called  radioisotope 
 any of several species of the same chemical element with different masses whose nuclei are unstable and dissipate excess energy by spontaneously emitting radiation in the form of alpha, beta, and gamma rays.

      A brief treatment of radioactive isotopes follows. For full treatment, see isotope: Radioactive isotopes (isotope).

      Every chemical element has one or more radioactive isotopes. For example, hydrogen, the lightest element, has three isotopes with mass numbers 1, 2, and 3. Only hydrogen-3 ( tritium), however, is a radioactive isotope, the other two being stable. More than 1,000 radioactive isotopes of the various elements are known. Approximately 50 of these are found in nature; the rest are produced artificially as the direct products of nuclear reactions or indirectly as the radioactive descendants of these products.

      Radioactive nuclides, or radionuclides, are species of unstable atomic nuclei without the restriction of being forms of the same element. Radioactive nuclides consist of all the sets of radioactive isotopes.

      Radioactive isotopes have many useful applications. In medicine, for example, cobalt-60 is extensively employed as a radiation source to arrest the development of cancer. Other radioactive isotopes are utilized as tracers for diagnostic purposes, as well as in research on metabolic processes. When a radioactive isotope is added in small amounts to comparatively large quantities of the stable element, it behaves exactly the same as the ordinary isotope chemically; it can, however, be traced with a Geiger counter or other detection device. Iodine-131 has proved effective in locating brain tumours, measuring cardiac output, and determining liver and thyroid activity. Another medically important radioactive isotope is carbon-14, which is useful in studying abnormalities of metabolism that underlie diabetes, gout, anemia, and acromegaly.

      In industry, radioactive isotopes of various kinds are used for measuring the thickness of metal or plastic sheets; their precise thickness is indicated by the strength of the radiations that penetrate the material being inspected. They also may be employed in place of large X-ray machines to examine manufactured metal parts for structural defects. Other significant applications include the use of radioactive isotopes as compact sources of electrical power (electric power)—e.g., plutonium-238 in cardiac pacemakers and spacecraft. In such cases, the heat produced in the decay of the radioactive isotope is converted into electricity by means of thermoelectric junction circuits or related devices.

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Universalium. 2010.

Look at other dictionaries:

  • radioactive isotope — radioactive isotope. См. радиоактивный изотоп. (Источник: «Англо русский толковый словарь генетических терминов». Арефьев В.А., Лисовенко Л.А., Москва: Изд во ВНИРО, 1995 г.) …   Молекулярная биология и генетика. Толковый словарь.

  • radioactive isotope — radioizotopas statusas T sritis fizika atitikmenys: angl. radioactive isotope; radioisotope vok. radioaktives Isotop, n; Radioisotop, n rus. радиоактивный изотоп, m; радиоизотоп, m pranc. isotope radioactif, m; radio isotope, m …   Fizikos terminų žodynas

  • radioactive isotope — radioaktyvusis izotopas statusas T sritis apsauga nuo naikinimo priemonių apibrėžtis Radioaktyviojo cheminio elemento izotopas. atitikmenys: angl. radioactive isotope; radioisotope rus. радиоизотоп …   Apsaugos nuo naikinimo priemonių enciklopedinis žodynas

  • radioactive isotope — radioisotope …   Medical dictionary

  • radioactive-isotope method — Смотри метод радиоактивных изотопов …   Энциклопедический словарь по металлургии

  • naturally radioactive isotope — gamtinis radioizotopas statusas T sritis fizika atitikmenys: angl. naturally radioactive isotope vok. natürliche Radioisotop, n rus. природный радиоактивный изотоп, m pranc. isotope radioactif naturel, m …   Fizikos terminų žodynas

  • Isotope geochemistry — is an aspect of geology based upon study of the relative and absolute concentrations of the elements and their isotopes in the Earth. Broadly, the field is divided into two branches: stable and radiogenic isotope geochemistry.Lead lead isotope… …   Wikipedia

  • isotope — isotopic /uy seuh top ik/, adj. isotopically, adv. /uy seuh tohp /, n. Chem. any of two or more forms of a chemical element, having the same number of protons in the nucleus, or the same atomic number, but having different numbers of neutrons in… …   Universalium

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  • isotope — n. a radioactive isotope * * * a radioactive isotope …   Combinatory dictionary


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