Simulation Study of Material Decomposition in Dual-Energy Radiography for Bone Removal

Dual-energy X-ray imaging provides additional image information, which can be exploited to conduct material decomposition. Using a projection-domain material decomposition approach is expected to be superior to a weighted logarithmic subtraction. The path length of bone and water per-pixel in an image can be calculated by interpolation in precalculated look-up tables of low- and high-energy attenuation values. Precalculation of the attenuation values makes an accurate spectrum estimation necessary. This can be achieved by adjusting the tube voltage and inherent aluminum (Al) filtration of an analytical X-ray spectrum model. When applied to ray-tracing simulation data, projection-domain decomposition outperforms a weighted logarithmic subtraction. When applied to measurement data without any scatter correction applied, the combination of spectrum estimation and look-up table-based decomposition provides images that are qualitatively comparable to them obtained by weighted logarithmic subtraction. Images obtained by look-up table-based decomposition show artefacts that are most likely due to the presence of scatter which we plan to tackle in the future.