Pulse detection logic for multibin photon counting detectors: Beyond the simple comparator

Scott S. Hsieh, Norbert J. Pelc

Research output: Chapter in Book/Report/Conference proceedingConference contribution

2 Scopus citations


Energy-discriminating, photon counting (EDPC) detectors have been proposed for CT systems for their spectral imaging capabilities, improved dose efficiency and higher spatial resolution. However, these advantages disappear at high flux because of the damaging effects of pulse pileup. From an information theoretic standpoint, spectral information is lost. The information loss is particularly high when we assume that the EDPC detector extracts information using a bank of comparators, as current EDPC detectors do. We analyze the use of alternative pulse detection logic which could preserve information in the presence of pileup. For example, the peak-only detector counts only a single event at the peak energy of multiple pulses which are piled up. We describe and evaluate five of these alternatives in simulation by numerically estimating the Cramer-Rao lower bound of the variance. At high flux, alternative mechanisms outperform comparators. In spectral imaging tasks, the variance reduction can be as high as an order of magnitude.

Original languageEnglish (US)
Title of host publicationMedical Imaging 2015
Subtitle of host publicationPhysics of Medical Imaging
EditorsChristoph Hoeschen, Despina Kontos, Christoph Hoeschen
ISBN (Electronic)9781628415025
StatePublished - 2015
EventMedical Imaging 2015: Physics of Medical Imaging - Orlando, United States
Duration: Feb 22 2015Feb 25 2015

Publication series

NameProgress in Biomedical Optics and Imaging - Proceedings of SPIE
ISSN (Print)1605-7422


OtherMedical Imaging 2015: Physics of Medical Imaging
Country/TerritoryUnited States


  • Photon counting x-ray detectors
  • Pulse pile-up
  • Spectral CT

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Atomic and Molecular Physics, and Optics
  • Biomaterials
  • Radiology Nuclear Medicine and imaging


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