Multiple energy computed tomography with monochromatic X-rays from the NSLS

Monochromatic X-rays from the X17 superconducting wiggler beamline at the National Synchrotron Light Source (NSLS) were used for dual-energy quantitative computed tomography (CT) of a 27-ram-diameter phantom containing solutions of different KOH concentrations in cylindrical holes of 5-mm diameter. The CT configuration was a fixed horizontal fan-shaped beam of 1.5-mm height and 30-mm width, and a subject rotating around a vertical axis. The transmitted X-rays were detected by a linear-array Si(Li) detector with 120 elements of 0.25-mm width each. A two-crystal Bragg-Bragg fixed-exit monochromator with Si<220> crystals was used. Dual photon absorptiometry CT data were taken at 20 and 38 keV. The reconstructed phantom images show the potential of the system for quantitative CT.<
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