Image covariance and lesion detectability in direct fan-beam x-ray CT
نویسندگان
چکیده
We consider noise in computed tomography images that are reconstructed using the classical direct fan-beam filtered backprojection algorithm, from both fulland short-scan data. A new, accurate method for computing image covariance is presented. The utility of the new covariance method is demonstrated by its application to the implementation of a channelized Hotelling observer for a lesion detection task. Results from the new covariance method and its application to the channelized Hotelling observer are compared with results from Monte Carlo simulations. In addition, the impact of a bowtie filter and x-ray tube current modulation on reconstruction noise and lesion detectability are explored for full-scan reconstruction.
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