Compensation of nonlinear distortions in photon-counting spectral CT: deadtime loss, spectral response, and beam hardening effects

Autor: Qiulin Tang, Jochen Cammin, Katsuyuki Taguchi, Neal E. Hartsough, Somesh Srivastava, William C. Barber, J.S. Iwanczyk
Rok vydání: 2012
Předmět:
Zdroj: SPIE Proceedings.
ISSN: 0277-786X
DOI: 10.1117/12.911217
Popis: Photon counting detectors are an emerging technology for spectral computed tomography. They have the potential to improve tissue contrast and specificity, reduce dose, and enable novel applications for K-edge and functional imaging. In this presentation various non-linear distortions were investigated that affect the image quality in photon-counting spectral CT: deadtime losses and spectral response, inherent to the new technology, and beam hardening artifacts that stem from the use of a polychromatic x-ray source. These effects were corrected or compensated for by performing calibration measurements. Techniques from material decomposition were applied to reconstruct images at a desired energy. Two methods were compared to synthesize a single monoenergetic image from photon counting data with multiple energy bins. The parameters were optimized to maximize a given image quality index. The procedures were evaluated on phantom data acquired on an experimental CT scanner with photon-counting detectors with two energy thresholds.
Databáze: OpenAIRE