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1784651 
Journal Article 
Thallium-201 for Myocardial Imaging. Relation of Thallium-201 to Regional Myocardial Perfusion 
Strauss, HW; Harrison, K; Langan, JK; Lebowitz, E; Pitt, B 
1975 
Yes 
Circulation
ISSN: 0009-7322
EISSN: 1524-4539 
NIOSH/00129758 
51 
4 
641-645 
English 
1116254 
The suitability of thallium-201 (15064650) (Tl-201) for use in myocardial scans was assessed by studying tissue distribution and regional myocardial distribution in mice and dogs. Mice were given 1 microCurie (microCi) intravenous (iv) Tl-201, potassium-43 (14903027) (K-43), or rubidium-81 (18268343) (Rb-811). Animals were sacrificed at intervals up to 120 minutes, and concentrations of tracers were determined in various organs. Anesthetized dogs, some with occluded left anterior descending coronary artery, were given 500microCi iv Tl-201 or K-43, and scans of the regional myocardial distribution of tracer were performed. Animals were sacrificed 5 to 30 minutes after treatment, and myocardial sections were examined for tracer concentrations. Other dogs in which partial occlusion or reactive hyperemia had been induced were similarly tested with 200microCi iv Tl-201, or with microspheres labelled with 50microCi strontium-85 (13967732) or chromium-51 (14392020) and injected into the left atrium. At 2 minutes posttreatment, Tl-201 concentrations were greater in heart and blood and smaller in liver and kidney than those of K-43 or Rb-81. Tl-201 blood clearance was nearly as rapid as that of K-43 and Rb-81, while myocardial clearance was slower, giving a maximum heart/blood ratio in the mouse at 10 minutes. In occluded dogs, the lesion was demonstrated with both Tl-201 and K-43, but was better defined with Tl-201. In all dogs, thallium was increased in regions of increased blood flow, but was not increased to the same extent as perfusion in reactive hyperemia. K-43 did not increase significantly during reactive hyperemia. The correlation coefficient for determinations of regional distribution of thallium versus microspheres was 0.97. The authors conclude that Tl-201 is an attractive tracer for the evaluation of regional myocardial perfusion. 
DCN-118325; Animal studies; Toxicology; Myocardial disorders; Anesthesiology; Metabolic study; Circulatory system; Toxic effects; Metabolism; Biological systems