[en] We investigated preliminarily the clinical utility of dynamic SPECT in studying pulmonary Xenon-133 gas washout, using the continuous repetitive rotating acquisition method with a triple-headed SPECT system. The subjects included one healthy volunteer and 16 various lung diseases. After obtaining the equilibrium images, the sequential washout images were acquired every 60 sec for 6 min. As the ventilation index, the real half-time of regional activity was evaluated. With or without abnormalities on chest CT, these images allowed us to show effectively the three-dimensional distribution of ventilation abnormalities, such as peripheral or segmental air trapping. Xenon-133 washout SPECT is useful to elucidate the distribution and nature of ventilation abnormalities in various diseases. (author)