The purpose of the study is the development of PET/CT protocols using 11C-CSar for human use. PET/CT methods developed in the pig studies are translated to studies in healthy humans and patients with cholestatic disorders. Dynamic PET/CT scans of the liver and biliary system are combined with measurements of tracer concentrations in a radial artery and a liver vein and measurements of hepatic blood flow by intravenous infusion of indocyanine green (ICG)/Ficks principle. Kinetic parameters from PET/CT measurements and invasive measurements are compared for validation of the PET estimated parameters and refinement of the PET modeling, if required.