radioactive isotope


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radioactive isotope

or

radioisotope,

natural or artificially created isotopeisotope
, in chemistry and physics, one of two or more atoms having the same atomic number but differing in atomic weight and mass number. The concept of isotope was introduced by F.
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 of a chemical element having an unstable nucleus that decays, emitting alpha, beta, or gamma rays until stability is reached. The stable end product is a nonradioactive isotope of another element, i.e., radium-226 decays finally to lead-206. Very careful measurements show that many materials contain traces of radioactive isotopes. For a time it was thought that these materials were all members of the actinide seriesactinide series,
a series of radioactive metallic elements in Group 3 of the periodic table. Members of the series are often called actinides, although actinium (at. no. 89) is not always considered a member of the series.
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; however, exacting radiochemical research has demonstrated that certain of the light elements also have naturally occurring isotopes that are radioactive. Since minute traces of radioactive isotopes can be sensitively detected by means of the Geiger counter and other methods, they have various uses in medical therapy, diagnosis, and research. In therapy, they are used to kill or inhibit specific malfunctioning cells. Radioactive phosphorus is used to treat abnormal cell proliferation, e.g., polycythemia (increase in red cells) and leukemia (increase in white cells). Radioactive iodine can be used in the diagnosis of thyroid function and in the treatment of hyperthyroidism. Since the iodine taken into the body concentrates in the thyroid gland, the radioaction can be confined to that organ. In research, radioactive isotopes as tracertracer,
an identifiable substance used to follow the course of a physical, chemical, or biological process. In chemistry the ideal tracer has the same chemical properties as the molecule it replaces and undergoes the same reactions but can at all times be detectible and
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 agents make it possible to follow the action and reaction of organic and inorganic substances within the body, many of which could not be studied by any other means. They also help to ascertain the effects of radiation on the human organism (see radiation sicknessradiation sickness,
harmful effect produced on body tissues by exposure to radioactive substances. The biological action of radiation is not fully understood, but it is believed that a disturbance in cellular activity results from the chemical changes caused by ionization (see
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). In industry, radioactive isotopes are used for a number of purposes, including measuring the thickness of metal or plastic sheets by the amount of radiation they can stop, testing for corrosion or wear, and monitoring various processes.

radioactive isotope

[¦rād·ē·ō′ak·tiv ′ī·sə‚tōp]
(nuclear physics)
References in periodicals archive ?
The post Russia finds 1,000-times normal level of radioactive isotope appeared first on Cyprus Mail .
The data also reveal that regular measurements of radiation exposure and radiation protective measures need not be undertaken in theatres where surgeons are working with radioactive isotopes regularly.
t] is the amount of radioactive isotope at time t, and [N.
Electron beam and X-ray irradiators--irradiation facilities--are operated by electricity and do not use radioactive isotopes.
Radioactive isotopes can continue to release energy over periods ranging from weeks to decades.
The contractors had not actually started work with the radioactive isotope but, nevertheless, safety procedures were broken.
Now that TRIUMF researchers have successfully accelerated this unstable radioactive isotope, a significantly broader range of research can be undertaken at TRIUMF.
A radioactive isotope emits x-rays at a few discrete energy values.
Charles Rock Road with unusually high levels of Thorium 230, a radioactive isotope that has been linked to certain types of cancer.
In this study, researcher Haolan Tang and Nicolas Dauphas from the University of Chicago found the radioactive isotope iron 60 -- the telltale sign of an exploding star-low in abundance and well mixed in solar system material.
The helium nucleus breaks and produces one hydrogen nucleus (a proton) and an atom of hydrogen's radioactive isotope, tritium.
Mr Litvinenko, a Kremlin critic who was granted asylum in Britain, died in late November after ingesting the rare radioactive isotope, polonium-210.

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