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PubMed · 492079

Detectability in computed tomographic images.

K M Hanson
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Abstract

The detection limitations inherent in statistically limited computed tomographic (CT) images are described through the application of signal detection theory. The detectability of large-area, low-contrast objects is shown to be chiefly dependent upon the low-frequency content of the noise power spectral density. For projection data containg uncorrelated noise, the resulting ramplike, low-frequency behavior of the noise power spectrum of CT reconstructions may be conveniently characterized by the number of noise-equivalent x-ray quanta (NEQ) detected in the projection measurements. The NEQ for a given image may be determined either from a measurement of the noise power spectrum or from the noise granularity computed with an appropriate weighting function. A measure of the efficiency of scanner dose utilization is proposed which compares the average dose to that required by an ideal scanner to obtain the same NEQ.

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HumansInformation TheoryStatistics as TopicTechnology, RadiologicTomography, X-Ray ComputedJournal Article

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K M Hanson. Detectability in computed tomographic images.. https://doi.org/10.1118/1.594534

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