[Thallium-201 uptake in lung and heart with different types of stress. Study in healthy volunteers]

Forty healthy male volunteers, aged 1,7 +/- 0.9 years, were studied to verify any possible differences in lung and heart Thallium-201 uptake with different types of stress. All of them were studied with myocardial perfusion SPECT after the injection of 201Thallium. The 40 individuals were randomized into four groups of 10 subjects and each group was subjected to a different type of stress: physical exercise, dobutamine, dipyridamole and adenosine triphosphate (ATP). Significant differences were observed with regard to lung and heart 201Thallium uptake, both of them being lower with physical exercise than with any of the drugs. However, the lung/heart ratio was equivalent for all the groups. We conclude that, even though physical exercise induces a lower lung and heart 201Thallium uptake than does pharmacological stress, the lung/heart ratio is comparable in the four types of stress and has a value of 0.28 +/- 0.03 in healthy young subjects.