Effects of powder morphology and particle size on CT number estimates

We performed experiments and data analysis to determine how powder morphology and particle size affect X-ray attenuation (CT number or CTN). These experiments were performed on a CT system with an isotropic resolution of (0.15 mm)3, and an endpoint energy of 160kV. Powders with effective atomic number (Ze) within ±0.2 of water were found to have CTN more directly related to electron density than to bulk physical density. Variations in mean particle size ranging between 2 μm and 44 μm were found to have no effect on specimen mean CTN.