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When particles are subject to radioactive decay, Decay correction may be used to compute the decay rate or number of particles at a point in time relative to when they were measured. This is necessary when comparing measurements obtained at different points in time. For example, the decay rate of a parent radionuclide is proportional to the number of atoms; as time passes some of atoms decay into daughter nuclides reducing the number of parent atoms. ==Use== For example, in biodistribution studies, it is common to track the movement of a compound of interest through an animal. To measure the compound it is chemically joined to a radionuclide. Thus the energy measured from the radioactive decay is related to the quantity of the compound of interest. Samples may be collected and counted at short time intervals (ex: 1 and 4 hours). The next samples (from another set of animals injected at the same starting time) may not be collected and counted until 24, 48, or 72 hours. Because isotopes for therapy and imaging often have a relatively short half-life (under 10 days), it is necessary to adjust the data in order to compare all the time points. For example, the isotope copper-64, commonly used in medical research, has a half-life of 12.7 hours. If you inject a large group of animals at "time zero", but measure the radioactivity in their organs at two later times, the later groups must be "decay corrected" to adjust for the decay that has occurred between the two time points. 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Decay correct」の詳細全文を読む スポンサード リンク
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