Quantitative dual-energy micro-CT with a photon-counting detector for material science and non-destructive testing

Abstract

The recent progress in photon-counting detector technology using high-Z semiconductor sensors provides new possibilities for spectral x-ray imaging. The benefits of the approach to extract spectral information directly from measurements in the projection domain are very advantageous for material science studies with x-rays as polychromatic artifacts like beam-hardening are handled properly. Since related methods require accurate knowledge of all energy-dependent system parameters, we utilize an adapted semi-empirical model, which relies on a simple calibration procedure. The method enables a projection-based decomposition of photon-counting raw-data into basis material projections. The objective of this paper is to investigate the method’s performance applied to x-ray micro-CT with special focus on applications in material science and non-destructive testing. Projection-based dual-energy micro-CT is shown to be of good quantitative accuracy regarding material properties such as electron densities and effective atomic numbers. Furthermore, we show that the proposed approach strongly reduces beam-hardening artifacts and improves image contrast at constant measurement time.

Dual-Energy X-Ray Dark-Field Material Decomposition

“…4) shows that quantitative thickness values can be retrieved reliably utilizing the calibration-based dark-field material decomposition approach. However, the achieved quantitative accuracy is inferior to results for attenuation-based material decomposition methods relying on empirical forward models [46], [47]. In our experiments, this can be attributed at least partly to inaccuracies in the line integral values of the calibration and test-grid.…”

Photon-counting spectral basis component material decomposition for musculoskeletal radiographs

“…The materials PVC and PMMA were chosen for calibration since their energy-dependent attenuation properties resemble those of bone and soft-tissue accurately. The quantitative accuracy of the decomposed line-integral values was evaluated in prior studies in numerical simulations 8 as well as experimental measurements 37 .…”

Guidelines for Micro–Computed Tomography Analysis of Rodent Dentoalveolar Tissues

“…These techniques are currently being developed, and clinical applications are emerging (104). Dualenergy quantitative X-ray tomography, in which a dual energy X-ray source is combined with the resolution of individual photon energy in the detector, is currently being developed and has an even greater potential in resolving materials that feature disparate densities within one sample (105). However, practical uses of these technologies are still under development.…”

“…(103) Dual-energy quantitative X-ray tomography, in which a dual-energy X-ray source is combined with the resolution of individual photon energy in the detector, is currently being developed and has an even greater potential in resolving materials that feature disparate densities within one sample. (104) However, practical uses of these technologies are still under development. Alternatively, imaging processing algorithms have been proposed to reduce metal and other artifacts in CT scans, (92,105,106) although, to our knowledge, these methods have been primarily implemented for CT, and few studies have translated them to μCT analysis.…”