Single-Shot Quantitative X-ray Imaging from Simultaneous Scatter and Dual Energy Measurements: A Simulation Study

Conventional x-ray imaging struggles with quantitation due to several challenges, including scatter, beam hardening, and multiple overlaying materials. We propose a new single-shot quantitative imaging (SSQI) method enabled by the combination of a primary modulator and a dual-layer detector to quantify area density of specific materials. The primary modulator enables scatter correction for the dual-layer detector, and the dual-layer detector enables beam hardening correction for the primary modulator. The dual-layer detector further provides motion-free dual-energy imaging from a single shot. When combined, the scatter-corrected dual-energy images can be used to create material-specific images, including of soft tissue, bone, or iodine. A simulation study was performed of SSQI for chest x-ray imaging. We simulated projections of a digital chest phantom using a 120 kV spectrum, primary modulator, and dual-layer detector, with the addition of scatter and noise. Using the low-frequency property of scatter, a pre-calibrated material decomposition, and the known primary modulator pattern, we jointly recovered the scatter images in the dual-layer images and the material decomposition of the phantom. The resulting material decomposition accurately separated soft tissue from bone, reducing the RMSE in material-specific images by 66-84% as compared to no scatter correction. Through this simulation study, we have demonstrated the potential of SSQI for material quantification that is robust against scatter. The simplicity and broad applicability of SSQI to x-ray systems has the potential for widespread adoption, leading to improved quantitative imaging not only for chest x-ray but also for real-time image guidance and for cone-beam CT.