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Modeling the performance of a photon counting x-ray detector for CT: Energy response and pulse pileup effects

By Katsuyuki Taguchi, Mengxi Zhang, Eric C. Frey, Xiaolan Wang, Jan S. Iwanczyk, Einar Nygard, Neal E. Hartsough, Benjamin M. W. Tsui and William C. Barber

Abstract

Purpose: Recently, photon counting x-ray detectors (PCXDs) with energy discrimination capabilities have been developed for potential use in clinical computed tomography (CT) scanners. These PCXDs have great potential to improve the quality of CT images due to the absence of electronic noise and weights applied to the counts and the additional spectral information. With high count rates encountered in clinical CT, however, coincident photons are recorded as one event with a higher or lower energy due to the finite speed of the PCXD. This phenomenon is called a “pulse pileup event” and results in both a loss of counts (called “deadtime losses”) and distortion of the recorded energy spectrum. Even though the performance of PCXDs is being improved, it is essential to develop algorithmic methods based on accurate models of the properties of detectors to compensate for these effects. To date, only one PCXD (model DXMCT-1, DxRay, Inc., Northridge, CA) has been used for clinical CT studies. The aim of that study was to evaluate the agreement between data measured by DXMCT-1 and those predicted by analytical models for the energy response, the deadtime losses, and the distorted recorded spectrum caused by pulse pileup effects

Topics: Radiation Imaging Physics
Publisher: American Association of Physicists in Medicine
OAI identifier: oai:pubmedcentral.nih.gov:3045417
Provided by: PubMed Central
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