Althogh the pulmonary funutional disorder of patients with pneumoconiosis thought to be a restrictive change selective alveolo-bronchography and postmortem pathological studies have shown that such patients also have an obstructive change. Ventilation examinations, including single breath, equilibrium and wash-out, using Xe-133 gas and perfusion examiations using Tc-99m MAA were done in 24 patients with pneumoconiosis. The patients were divided into four types according to the classification of chest X-ray findings of the Japanese labour Ministry: type I, 7pts type II, 6pts: 6pts: type III, 7pts, and type IV, 4pts. There were many abnomal findings in the upper ung field in the single breath phase ((133)Xe gas) and also in the perfusion study. (133)Xe retention was found in the upper lung field in of type I patients, and also in the middle and lower lung fields according to the seriousness of the patient's condition fromctype II to type IV. The mean transit time in the region of interest of the lung field increased with increasing seriousness of disease. These studies show that patients with pneumoconiosis have not only restrictive changes, but also obstructive changes even in the early stage.
(99m)Tc-MAA perfusion study