[en] The platelet thrombogenicity of a hemodialyzer was quantified with ^99mTc- and ¹¹¹In-labeled platelets. The platelets collected from blood of Beagle dogs, Yorkshire pigs and humans were labeled with ¹¹¹In-tropolone (detergent-free) and ^99mTc-HMPAO. Hemodialysis was performed with a hollow-fiber dialyzer (HFD) in a flow-loop, the temperature maintained at 37^oC, with flow-rates of 7, 150 and 270 mL/min; after dialysis, HFD radioactivity was measured with an ionization chamber and imaged with a γ-camera. The dynamic processes of thrombosis and embolization from the hemodialyzer resulted in large standard deviations around the mean values of the adherent thrombus. In spite of this, the quantitation of comparative thrombogenicity with ¹¹¹In-and ^99mTc-labeled platelets suggests that both radionuclides could be used for measurement of device-induced thrombogenicity and estimation of prosthesis-induced thrombogenicity. (author)