Spectral Distortion Compensation for Spectral CT

One of the challenges in photon counting detector (PCD)-based computed tomography (CT) is the spectral distortion in the PCD caused by physical effects such as charge sharing and K-escape fluorescence. This chapter summarizes for conventional approaches to compensate for the spectral distortion in PCD-CT and provides in great detail for a recently developed x-ray transmittance modeling-based three-step algorithm as a fast alternative to the maximum likelihood-based estimator. We describe both theoretical and practical aspects of the algorithm and also provide an example of two-material decomposition with practical implementations.