Refinement of Exponents for the Photoelectric Absorption in Dual-Energy CT Applications

Dual-energy (DE) CT is an emerging CT operation mode, which has the potential of enabling new and improved artifact reduction methods. Additionally, it introduces functional imaging techniques, which were previously not available on standard CT scanners. The basis of almost all DE reconstruction methods is the assumption that the linear attenuation coefficient can be approximated by two physical processes: the photoelectric absorption and Compton scatter. Unfortunately, the approximation of the photoelectric absorption contains two constant exponents for which appropriate values must be chosen to allow a good approximation. Therefore, in the present work, values for these constants are derived from measured attenuation data and are additionally compared to values found in literature.