REGIONAL DISTRIBUTION OF TL-201 DURING ONE-LEG EXERCISE - COMPARISON WITH LEG BLOOD-FLOW BY PLETHYSMOGRAPHY

To validate the use of Tl-201 distribution as an estimate of regional blood flow in the legs, Tl-201 leg up-take was compared by whole body scintigraphy and simultaneously measured leg blood flow by plethysmogr aphy during one-leg exercise in 11 male subjects. Tl-201 leg uptake ra tio and leg blood flow ratio were also compared to exclude the effect of cardiac output variation in each subject. There was a good correlat ion between Tl-201 leg uptake and leg blood flow (r = 0.85, P < 0.01, y = 0.28x + 1.00). Moreover, there was a highly linear correlation bet ween these ratios (r = 0.98, P < 0.01, y = 0.75x + 0.13), although the Tl-201 leg uptake ratio somewhat underestimated the leg blood flow ra tio as exercise became strenuous. It is concluded that Tl-201 leg upta ke reflects regional blood flow in the legs during exercise.