title: Evaluation of models of spectral distortions in photon-counting detectors for computed tomography.
abstract: A semi-analytical model describing spectral distortions in photon-counting detectors (PCDs) for clinical computed tomography was evaluated using simulated data. The distortions were due to count rate-independent spectral response effects and count rate-dependent pulse-pileup effects and the model predicted both the mean count rates and the spectral shape. The model parameters were calculated using calibration data. The model was evaluated by comparing the predicted x-ray spectra to Monte Carlo simulations of a PCD at various count rates. The data-model agreement expressed as weighted coefficient of variation [Formula: see text] was better than [Formula: see text] for dead time losses up to 28% and [Formula: see text] or smaller for dead time losses up to 69%. The accuracy of the model was also tested for the purpose of material decomposition by estimating material thicknesses from simulated projection data. The estimated attenuator thicknesses generally agreed with the true values within one standard deviation of the statistical uncertainty obtained from multiple noise realizations.
authors.affiliation: Johns Hopkins University School of Medicine , Division of Medical Imaging Physics, The Russell H. Morgan Department of Radiology and Radiological Science, 601 North Caroline Street, Baltimore, Maryland 21287, United States.
authors.forename: Jochen
authors.initials: J
authors.lastname: Cammin
authors.affiliation: Siemens Healthcare , Computed Tomography, Siemens Street 1, Forchheim 91301, Germany.
authors.forename: Steffen
authors.initials: S
authors.lastname: Kappler
authors.affiliation: Siemens Healthcare, Computed Tomography, Siemens Street 1, Forchheim 91301, Germany; University of Lübeck, Institute of Medical Engineering, Ratzeburger Allee 160, Lübeck 23562, Germany.
authors.forename: Thomas
authors.initials: T
authors.lastname: Weidinger
authors.affiliation: Johns Hopkins University School of Medicine , Division of Medical Imaging Physics, The Russell H. Morgan Department of Radiology and Radiological Science, 601 North Caroline Street, Baltimore, Maryland 21287, United States.
authors.forename: Katsuyuki
authors.initials: K
authors.lastname: Taguchi
keywords: compensation of spectral distortions; computed tomography; nonparalyzable detector; paralyzable detector; photon-counting; pulse pileup; spectral response