Pulmonary function studies with radioisotopes

Physiological studies on ventilation and lung perfusion by means of labelled gases and radioactive flow tracers have made valuable contributions to our knowledge of lung functions. But the same techniques for studying patients with lung diseases have not attained the same importance. This is partly due to the fact that the necessary equipment is complicated and expensive if results on regional functions should be obtained. A number of physical and physiological factors influence the results and make their interpretation more difficult than is usually recognized. If these problems can be solved, or at least evaluated to a reasonable extent, clinical studies on regional lung functions should become one of the major areas in nuclear medicine. (author)