Effects of different lung morphometry models on the calculated dose conversion factor from Rn progeny

To investigate the effect of different morphometry models on the calculation of the dose conversion factor, three morphometry models were used, namely Yeh–Schum asymmetrical lung model, as well as Weibel and ICRP66 symmetrical models. The original Yeh–Schum model was scaled according to the volume of the standard man, and the results for both the scaled and unscaled models were presented. Dose conversion factors (in mGy WLM−1) were obtained as a function of particle diameter, breathing rate and generation number. Comparison among different lung morphometry models showed that the Weibel and ICRP66 models gave larger dose conversion factors than the Yeh–Schum model, which was explained by the difference in their total surface areas of the tracheo-bronchial tree. The distribution of dose conversion factor in the first few generations was also found to be different among the examined models.