An improved method for simultaneous dual isotope Tc-99m/Tl-201 emission scintigraphy

Results are presented from a new method of Tc-99m crossover correction in dual-isotope Tc-99m/Tl-201 emission scintigraphy. This method, based on Monte Carlo simulations, utilizes a third (spilldown) image acquired in a narrow energy window to the right of the Tl-201 photopeak simultaneously with the Tc-99m and Tl-201 images. The Tc-99m spilldown image is multiplied by a conversion factor to approximate the Tc-99m crossover in the Tl-201 imaging window. The crossover Tc-99m image is then subtracted from the original Tl-201 image to produce the corrected Tl-201 image. This method was applied to dual-isotope Tc-99m/Tl-201 cardiac phantoms, with significant improvement in definition and accuracy of the Tl-201 images.<
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