Examples of radionuclide in the following topics:
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- An atom with an unstable nucleus, called a radionuclide, is characterized by excess energy available either for a newly created radiation particle within the nucleus or via internal conversion.
- During this process, the radionuclide is said to undergo radioactive decay.
- Radionuclides occur naturally but can also be produced artificially.
- All elements form a number of radionuclides, although the half-lives of many are so short that they are not observed in nature.
- The heaviest elements (heavier than bismuth) exist only as radionuclides.
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- The half-life of a radionuclide is the time taken for half the radionuclide's atoms to decay.
- The half-life of a radionuclide is the time taken for half of the radionuclide's atoms to decay.
- Half-lives of known radionuclides vary widely, from more than 1019 years, such as for the very nearly stable nuclide 209 Bi, to 10−23 seconds for highly unstable ones.
- The time constant τ is the e-1-life, the time until only 1/e remains -- about 36.8 percent, rather than the 50 percent in the half-life of a radionuclide.
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- The system detects pairs of gamma rays emitted indirectly by a positron-emitting radionuclide (tracer), which is introduced into the body on a biologically active molecule.
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- Radon and its isotopes, parent radionuclides, and decay products all contribute to an average inhaled dose of 1.26 mSv/a.
- The major radionuclides of concern are potassium, uranium, and thorium and their decay products.
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- The system detects pairs of gamma rays emitted indirectly by a positron-emitting radionuclide (tracer), which is introduced into the body on a biologically active molecule.
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- Numerous synthetic radionuclides of naturally occurring elements have also been produced in laboratories.
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- Half-lives have been determined in laboratories for thousands of radioisotopes (radionuclides).