[en] This thesis describes the clinical application of cholescintigraphy with sup(99m)Technetium-diethyl-IDA as hepato-biliary radiopharmaceutical. After a review of some anatomical and physiological properties of liver and biliary tract the conceptions jaundice and cholestasis are defined. Various clinical investigations in patients with liver and biliary tract disorders are discussed such as biochemical blood examinations, liver biopsy and radiological investigations. The applications and limitations of colloid liver scintigraphy in patients with focal or diffuse liver diseases are reviewed. Furthermore the diagnostic value of this investigation in jaundiced patients is discussed. The literature study ends with a review of the application of various hepato-biliary radiopharmaceuticals and the development, properties and first application of IDA-derivates. The synthesis, preparation and quality control of diethyl-IDA which is available as an 'instant labelling kit' (Solco-HIDAsup(R)) is described. The biological properties of the radiopharmaceutical are studied by means of kinetic and autoradiographic investigations in rat. As introduction to the clinical studies the technical basis of cholescintigraphy is described that encompasses the performance of the serial scintigrams and the generation of time-activity curves and functional images by a computer. Cholescintigraphic patterns in individuals without liver or biliary tract disorders are shown. (Auth.)