Fig. 1
From: Dual-layer spectral computed tomography: measuring relative electron density
Gammex phantom with inserts simulating human tissue. a Photo of the phantom with twelve inserts (relative electron densities ranging from 0.264 to 1.696). b Conventional computed tomographic image. c and d Corresponding virtual mono-energetic images (50 keV and 200 keV). b–d The window level in these images is 50 HU with width of 350 HU. In the outer ring of the Gammex phantom, the insert with the highest intensity is cortical bone. The electron densities of twelve materials decreases counterclockwise