CT dual-energy decomposition into x-ray signatures Rho-e and Z-e

Harry E. Martz; Issac M. Seetho; Kyle E. Champley; Jerel A. Smith; Stephen G. Azevedo

doi:10.1117/12.2228954

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12 May 2016 CT dual-energy decomposition into x-ray signatures ρ_e and Z_e

Harry E. Martz, Issac M. Seetho, Kyle E. Champley, Jerel A. Smith, Stephen G. Azevedo

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Proceedings Volume 9847, Anomaly Detection and Imaging with X-Rays (ADIX); 98470D (2016) https://doi.org/10.1117/12.2228954
Event: SPIE Defense + Security, 2016, Baltimore, Maryland, United States

Abstract

In a recent journal article [IEEE Trans. Nuc. Sci., 63(1), 341-350, 2016], we introduced a novel method that decomposes dual-energy X-ray CT (DECT) data into electron density (ρ_e) and a new effective-atomic-number called Z_e in pursuit of system-independent characterization of materials. The Z_e of a material, unlike the traditional Z_eff, is defined relative to the actual X-ray absorption properties of the constituent atoms in the material, which are based on published X-ray cross sections. Our DECT method, called SIRZ (System-Independent ρ_e, Z_e), uses a set of well-known reference materials and an understanding of the system spectral response to produce accurate and precise estimates of the X-ray-relevant basis variables (ρ_e, Z_e) regardless of scanner or spectra in diagnostic energy ranges (30 to 200 keV). Potentially, SIRZ can account for and correct spectral changes in a scanner over time and, because the system spectral response is included in the technique, additional beam-hardening correction is not needed. Results show accuracy (<3%) and precision (<2%) values that are much better than prior methods on a wide range of spectra. In this paper, we will describe how to convert DECT system output into (ρ_e, Z_e) features and we present our latest SIRZ results compared with ground truth for a set of materials.

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Harry E. Martz, Issac M. Seetho, Kyle E. Champley, Jerel A. Smith, and Stephen G. Azevedo "CT dual-energy decomposition into x-ray signatures ρ_e and Z_e", Proc. SPIE 9847, Anomaly Detection and Imaging with X-Rays (ADIX), 98470D (12 May 2016); https://doi.org/10.1117/12.2228954

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