Physics of Medical Imaging

Evaluation of models of spectral distortions in photon-counting detectors for computed tomography

[+] Author Affiliations
Jochen Cammin, Katsuyuki Taguchi

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

Steffen Kappler

Siemens Healthcare, Computed Tomography, Siemens Street 1, Forchheim 91301, Germany

Thomas Weidinger

Siemens Healthcare, Computed Tomography, Siemens Street 1, Forchheim 91301, Germany

University of Lübeck, Institute of Medical Engineering, Ratzeburger Allee 160, Lübeck 23562, Germany

J. Med. Imag. 3(2), 023503 (May 06, 2016). doi:10.1117/1.JMI.3.2.023503
History: Received October 10, 2015; Accepted April 7, 2016
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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 (COVW) was better than COVW=2.0% for dead time losses up to 28% and COVW=20% 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.

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© 2016 Society of Photo-Optical Instrumentation Engineers

Citation

Jochen Cammin ; Steffen Kappler ; Thomas Weidinger and Katsuyuki Taguchi
"Evaluation of models of spectral distortions in photon-counting detectors for computed tomography", J. Med. Imag. 3(2), 023503 (May 06, 2016). ; http://dx.doi.org/10.1117/1.JMI.3.2.023503


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