Material separation in x-ray CT with energy resolved photon-counting detectors

X. Wang; D. Meier; K. Taguchi; D. J. Wagenaar; B. E. Patt; E. C. Frey

doi:10.1117/12.877469

16 March 2011 Material separation in x-ray CT with energy resolved photon-counting detectors

X. Wang, D. Meier, K. Taguchi, D. J. Wagenaar, B. E. Patt, E. C. Frey

Proceedings Volume 7961, Medical Imaging 2011: Physics of Medical Imaging; 79611V (2011) https://doi.org/10.1117/12.877469
Event: SPIE Medical Imaging, 2011, Lake Buena Vista (Orlando), Florida, United States

Abstract

The objective of the study was to demonstrate that more than two types of materials can be effectively separated with x-ray CT using a recently developed energy resolved photon-counting detector. We performed simulations and physical experiments using an energy resolved photon-counting detector with six energy thresholds. For comparison, dual-kVp CT with an integrating detector was also simulated. Iodine- and gadolinium-based contrast agents, as well as several soft-tissue- and bone-like materials were imaged. We plotted the attenuation coefficients for the various materials in a scatter plot for pairs of energy windows. In both simulations and physical experiments, the contrast agents were easily separable from other non-contrast-agent materials in the scatter plot between two properly chosen energy windows. This separation was due to discontinuities in the attenuation coefficient around their unique K-edges. The availability of more than two energy thresholds in a photon-counting detector allowed the separation with one or more contrast agents present. Compared with dual-kVp methods, CT with an energy resolved photon-counting detector provided a larger separation and the freedom to use different energy window pairs to specify the desired target material. We concluded that an energy resolved photon-counting detector with more than two thresholds allowed the separation of more than two types of materials, e.g., soft-tissue-like, bone-like, and one or more materials with K-edges in the energy range of interest. They provided advantages over dual-kVp CT in terms of the degree of separation and the number of materials that can be separated simultaneously.

Citation Download Citation

X. Wang, D. Meier, K. Taguchi, D. J. Wagenaar, B. E. Patt, and E. C. Frey "Material separation in x-ray CT with energy resolved photon-counting detectors", Proc. SPIE 7961, Medical Imaging 2011: Physics of Medical Imaging, 79611V (16 March 2011); https://doi.org/10.1117/12.877469

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