Optimized Energy Bins for K-Edge Imaging Using a Photon Counting Detector

Abstract

K-edge imaging is a very effective enhanced imaging method, which is under intensive study in X-ray computed tomography (CT) area. The photon counting detector (PCD)-based spectral CT can measure the attenuation within the energy bins on both sides of the K-edge energy of contrast agents, such as iodine, gadolinium, etc. and obtain a large difference of the attenuation characteristics. Therefore, it has the potential to improve the image quality for the K-edge imaging and reduce the amount of contrast agents. This chapter mainly focuses on optimization technology of energy bins for K-edge imaging using a PCD-based spectral CT. The background and fundamental theory of K-edge imaging with spectral CT are introduced first. Then the influence of the energy bins used for the K-edge imaging based on the PCD is experimentally studied with phantom and mice imaging. Finally, a model of degradation effects of attenuation coefficient curve is described and an optimization method to determine energy bins for K-edge imaging is proposed. The optimized energy bins obtained by this method can better highlight the K-edge signal of the contrast agents, thus resulting better image quality than the conventional energy bin selection method.