le_w 18ew 74 (28.6%) 69,4d 112 114 LEFT IRIDIUM 191M DISTRIBUTION OF THIS DOCUMENT IS UNLIMITE_D report Ms been reproduceddirectly from the best available copy. Available to DOE and DOE contractors from the Office of Sc_ffic end Technical Information,P.O. Box 62, Oak Ridge, TN 37831; prices available from (615) 576-8401, FTS 826-8401. Available to the pub_ from the National Technical Infornmtion Service, U.S. Department of Commerce, 5285 Port Royal lid., Springfield,VA 22161.TNa report was prepared as an account of work sponsored by an agency of the United States Government. Neither the United States Government nor any agency thereof, nor any of their employees, makes any warranty, exprm or klq:4lad, or assumes any legal liability or re_oonslbilltyfor the accuracy, completeness, or usefulnessof any information,apparatus, product, or process disclosed, or rel)resem that its use would not infringe privately owned rights. Reference herein to any specific commercial product: proce_, or service by trade name, trademark, manufacturer, or otherwise, does not necessarily constitute or knply its endorsement,r,mornnwndstion,or favoringby the United States Government or any agency thereof. The views and opinions of authors expressed herein do not necessarily state or reflect those of the United States L Government or any agency thereof. CoverThe ORNL High Flux Reactor has the highest thermal neutron flux and is used to produce tungsten-188 which is the parent for a generator system providing carrier-free rhenium-188 for therapeutic applications. The end-diastolic and end-systolic left ventricular images obtained in a patient were measured with the ultra short-lived iridium-191m radioisotope (half-life 4.96 seconds). The images were kindly provided by P. Franken, M.D., from the Nuclear Medicine Department at the Free University of Brussels. lridium-191m was obtained from the osmium-191/iridium-19im generator developed at ORNL in conjunction with the Cyclotron Research Center in Liege, Belgium.