Local deposition distributions of inhaled radionuclides in the human tracheobronchial tree.
There is experimental evidence that bronchogenic carcinomas originate mainly at the carinal ridges of the large central airways, where primary hot spots of deposition have been found. However, current lung dosimetry models do not take into consideration the inhomogeneity of deposition within the airways. In this study, computed local distributions of deposited inhaled radionuclides such as radon progenies in morphologically realistic human airway bifurcation models are analysed for different flow rates and particle sizes. Then, local deposition enhancement factors, defined as the ratio of local to average deposition densities, are computed by scanning along the surface of the bifurcation with pre-specified surface area elements. Computed enhancement factors indicate that cells located at carinal ridges or at the inner sides of the progeny branches may receive localised doses which are two orders of magnitude higher than the average values.
KFKI Atomic Energy Research Institute, P.O. Box 49, H-1525 Budapest, Hungary. ibalas@sunserv.kfki.hu
I
I
Balásházy
A
A
Farkas
W
W
Hofmann
S
S
Kurunczi
D000280:Administration, Inhalation; D001980:Bronchi / Q000528:radiation effects*; D003198:Computer Simulation; D006801:Humans; D011868:Radioisotopes / Q000008:administration & dosage* / Q000493:pharmacokinetics*; D012143:Respiratory Physiological Phenomena / Q000528:radiation effects; D014132:Trachea / Q000528:radiation effects*
D011868:Radioisotopes