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

Jochen Cammin, Steffen Kappler, Thomas Weidinger, Katsuyuki Taguchi

Research output: Contribution to journalArticlepeer-review

15 Scopus citations

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=20% 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.

Original languageEnglish
Article number023503
JournalJournal of Medical Imaging
Volume3
Issue number2
DOIs
StatePublished - Apr 1 2016

Keywords

  • Computed tomography
  • compensation of spectral distortions
  • nonparalyzable detector
  • paralyzable detector
  • photon-counting
  • pulse pileup
  • spectral response

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