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Code
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Display
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Definition
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112183
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Standard Deviation of Attenuation Coefficient |
For a set of X-Ray attenuation coefficients: 1) a measure of the dispersion of a frequency distribution that is the square root of the arithmetic mean of the squares of the deviation of each of the class frequencies from the arithmetic mean of the frequency distribution; 2) a parameter that indicates the way in which a probability function or a probability density function is centered around its mean and that is equal to the square root of the moment in which the deviation from the mean is squared. |
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112031
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Attenuation Coefficient |
A quantitative numerical statement of the relative attenuation of the X-Ray beam at a specified point. Coefficient that describes the fraction of a beam of X-Rays or gamma rays that is absorbed or scattered per unit thickness of the absorber. This value basically accounts for the number of atoms in a cubic cm volume of material and the probability of a photon being scattered or absorbed from the nucleus or an electron of one of these atoms. Usually expressed in Hounsfield units [referred to as CT Number in Fraser and Pare]. |
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112179
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Minimum Attenuation Coefficient |
The least quantity assignable, admissible, or possible; the least of a set of X-Ray attenuation coefficients. |
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112180
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Maximum Attenuation Coefficient |
The greatest quantity or value attainable or attained; the largest of a set of X-Ray attenuation coefficients. |
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112181
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Mean Attenuation Coefficient |
The value that is computed by dividing the sum of a set of X-Ray attenuation coefficients by the number of values . |
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112182
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Median Attenuation Coefficient |
The value in an ordered set of X-Ray attenuation coefficients, below and above which there is an equal number of values. |