This collaborative effort of three organizations is directed toward a deeper understanding of pulmonary pathophysiology through the construction of computer-based models of pulmonary gas exchange and respiratory mechanics and the comparison of model predictions with real patient data. BIBLIOGRAPHIC REFERENCES: Line, B.R., Dayhoff, R.E., Bailey, J.J.: An algorithm for the production of regional gas partial pressures and blood contents from scintigraphic and physiologic data using an alveolar gas exchange model. Proceedings of The Seventh Symposium on Sharing Computer Programs and Technology in Nuclear Medicine. Society for Nuclear Medicine, 475 Park Avenue South, New York, N. Y., 10016 1977 (in press).