Resurrection of thallium-201 for myocardial perfusion imaging.

a D t t H w l c T t l t a e 9 2 r t c A i “ e 9 n a s t s r m m p i Thallium-201 has several virtues as a myocardial perfusion agent. It is one of the best of the soluble agents for measuring regional myocardial perfusion, because it has a blood clearance half-time of 30 s and a first pass extraction in the myocardium of 88% (1) (compared with the 1-min blood clearance half-time [2] and 50% to 60% first pass extraction of technetium-99m sestamibi) (3). These biological characteristics of thallium provide higher contrast between regions of normal perfusion and zones of ischemia, even on planar myocardial perfusion studies. Numerous publications confirmed the sensitivity, specificity, and diagnostic accuracy of myocardial perfusion imaging with thallium (4,5).