Accurate material quantification in dual energy CT

Clinical CT applications such as oncology follow-up using iodine maps require accurate contrast agent (CA) quantification within the patient. Unfortunately, due to beam hardening, the quantification of CA materials like iodine in dual energy systems can vary for different patient sizes and surrounding composition. In this paper we present a novel method that handles this problem which takes into account properly the CA energy dependent attenuation profile. Our method is applicable for different dual energy scanners, e.g. fast kVp switching or dual layer detector array and is fully compatible with image domain material analysis. In this paper we explain the concept of so called landmarks used by our method, and give the mathematical formulation of how to calculate them. We demonstrate by scans of various phantom shapes and by simulations, the robustness and the accuracy of the iodine concentration quantification obtained by our method.