CT measurement of lung density: The role of patient position and value for total body irradiation

Abstract To obtain more precise data on pulmonary doses in preparation for total body irradiation, the lung density of patients was systematically analyzed in treatment positions using data obtained by computed tomography (CT). With the patient supine, the lung density was not significantly different for the right and left lungs. In contrast, considerable differences were noted between the two lungs in lateral decubitus positions owing to variations in ventilation and perfusion. The relative electron density of lung was also found to decrease with age, dropping to ϱ e = 0.160 at 71 years.