Iterative reconstruction of the electron density and effective atomic number using a non-linear forward model

K. Aditya Mohan; Kyle M. Champley; Albert W. Reed; Steven M. Glenn; Harry E. Martz Jr.

doi:10.1117/12.2625136

3 June 2022 Iterative reconstruction of the electron density and effective atomic number using a non-linear forward model

K. Aditya Mohan, Kyle M. Champley, Albert W. Reed, Steven M. Glenn, Harry E. Martz Jr.

Author Affiliations +

Proceedings Volume 12104, Anomaly Detection and Imaging with X-Rays (ADIX) VII; 1210403 (2022) https://doi.org/10.1117/12.2625136
Event: SPIE Defense + Commercial Sensing, 2022, Orlando, Florida, United States

Abstract

For material identification, characterization, and quantification, it is useful to estimate system-independent material properties that do not depend on the detailed specifications of the X-ray computed tomography (CT) system such as spectral response. System independent ρ_e and Z_e (SIRZ) refers to a suite of methods for estimating the system independent material properties of electron density (ρ_e) and effective atomic number (Z_e) of an object scanned using dual-energy X-ray CT (DECT). The current state-of-the-art approach, SIRZ-2, makes certain approximations that lead to inaccurate estimates for large atomic numbered (Z_e) materials. In this paper, we present an extension, SIRZ-3, which iteratively reconstructs the unknown ρ_e and Z_e while avoiding the limiting approximations made by SIRZ-2. Unlike SIRZ-2, this allows SIRZ-3 to accurately reconstruct ρe and Z_e even at large Z_e. SIRZ-3 relies on the use of a new non-linear differentiable forward measurement model that expresses the DECT measurement data as a direct analytical function of ρ_e and Z_e. Leveraging this new forward model, we use an iterative optimization algorithm to reconstruct (or solve for) ρ_e and Z_e directly from the DECT data. Compared to SIRZ-2, we show that the magnitude of performance improvement using SIRZ-3 increases with increasing values for Z_e.

Conference Presentation

Citation Download Citation

K. Aditya Mohan, Kyle M. Champley, Albert W. Reed, Steven M. Glenn, and Harry E. Martz Jr. "Iterative reconstruction of the electron density and effective atomic number using a non-linear forward model", Proc. SPIE 12104, Anomaly Detection and Imaging with X-Rays (ADIX) VII, 1210403 (3 June 2022); https://doi.org/10.1117/12.2625136

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