Airflow distribution in the human lung and its influence on particle deposition.

Realistic descriptions of lung geometry and physiology are the primary determinants of accurate predictions of inhaled particle deposition and distribution in the human lung. While there have been considerable efforts devoted to geometry reconstruction, little attention has been given to lung ventilation as applied to particle deposition applications. Models of lung ventilation based on pressure differential between extrathoracic airways and the pleural cavity were developed and used to calculate lobar and regional deposition of particles in the human lung. Local airflow in the lung varied in accordance with regional physiological properties. Calculations showed that airflow rate entering each lobe was different for compliant and noncompliant lung models and similar for uniform and nonuniform lung expansions. Regional particle deposition predictions were almost identical between the two compliance models. However, differences in lobar depositions were observed. The coupled lung ventilation and deposition models can be used in site-specific deposition predictions of inhaled particles in the human lungs.