Contribution of the positron camera to studies of regional lung structure and function.

Positron emission tomography is a major technological advance in the characterisation of structure-function relationships within and between regions in normal and abnormal lungs (Hughes et al. 1985). The measurements are noninvasive and relatively exact since the geometric conditions are precisely defined. Regional expansion, flow (ventilation, perfusion), oxygen concentration (from VA/Q) and glucose metabolism can be measured in absolute terms per cubic centimetre of thorax or per gram of extravascular lung. Examples of structure-function relationships in normal subjects, emphysema, bronchitis and sarcoidosis are briefly presented.