Dual layer spectral CT allows to obtain information about the imaged materials in different regions of the x-ray spectrum. This spectral information can be used in different ways to increase the diagnostic value of CT imaging. For instance, it can be used to obtain material maps of the imaged objects for a set of known base materials. In this project, we collaborate with radiologists from the clinic for diagnostic and interventional radiology at UKE. Out aim is to improve the spectral CT based material decomposition methods. Moreover, we aim to develop new clinical applications for spectral CT-based material decomposition and assess the method's accuracy and robustness.