Gamma densigraphy in the evaluation of regional pulmonary ventilation

The importance of measuring regional ventilation is well accepted as a major parameter in the evaluation of regional pulmonary function. Although the perfusion lung scan has been widely used clinically, nuclide ventilatory studies have only recently achieved some degree of popularity. Gamma-densigraphy, a method based on the transmission of a gamma beam through a patient's chest and the measurement of the radiodensity changes with ventilation is described. This technique has the advantages of simplicity, low cost, and patient acceptability. It also yields information reflecting mechanics of respiration not readily obtained from the other commonly used methods for studying regional ventilation. Illustrative cases showing the clinical applications of this method are presented.