Myocardial imaging in dogs with thallium-201 and the ionophore grisorixin.

The effect of grisorixin, a monocarboxylic ionophore, upon the myocardium-to-background ratio in thallium-201 scintigrams has been studied in 20 dogs. Three sequences of injection and two doses of the ionophore have been used. A significant improvement was obtained when grisorixin was injected 10 min before thallium-201 and at a submaximal dose; the myocardium-to-background ratio was at least twice that of the controls during the first 20 min following the tracer injection.