The Radiation Dose Through the Human Lung Based on the Inhalation of Short-Lived Radon Progen

Direct measurements of an effective dose due to the inhalation of short lived radon progeny through the human lung is rarely, if ever, possible. Therefore, one must rely on dosimetric models to evaluate doses at different depths in bronchial epithelium. These models always require information about the parameters of activity size distributions and the activity concentration of short lived radon progeny (218Po, 214Pb, and 214Bi/214Po). In the present work, the attached and unattached activity size distributions of radon progeny were measured by using a low pressure cascade impactor and a wire screen diffusion battery, respectively. The mean activity concentrations of (218Po, 214Pb, and 214Bi/214Po) are found to be 7.5 ± 0.64, 6.3 ± 0.5 and 4.4 ±0.42 Bq/m3, respectively. An analytical method has been applied to estimate the local energy deposition of radon progeny alpha particles in a target volume of I am spheres located at different depths in bronchial epithelium. In order to reach the target, alpha particles travel either through tissue alone or through air and tissue. While the depth-dose distributions (for 218Po uniformly distributed within the epithelium) were practically constant with depth, they decreased in an almost linear fashion with increasing depth for 218Po on the airway surface