Implementation of Charged Particles Deposition in Stochastic Lung Model and Calculation of Enhanced Deposition

Abstract

The experimental studies using hollow lung cast of human tracheobronchial (TB) tree and in-vivo experiments have demonstrated enhanced charged deposition in the lung. The present study was carried out to implement charge particle deposition into the stochastic human lung model and to estimate enhanced deposition for various charged particles at the airway generation level. Enhanced deposition calculations of charged particles are performed by implementing two different efficiency equations derived for the TB and alveolar (Al) region. Deposition fractions of inhaled charged particles are computed by the stochastic airway generation model IDEAL (Inhalation, Deposition and Exhalation of Aerosols in the Lung) for various breathing conditions and particle sizes. Enhanced deposition of charged particles in the Al region is found to be up to five times higher than in the TB region. Enhanced deposition in the TB region is higher under sitting breathing condition than under light exercise breathing condition. The introduction of pause time, during inhalation, increases the probability of increased enhanced deposition up to a certain breath-hold time limit. The calculated enhancement factors (EF) reveals that more than two times higher deposition can be achieved in the lung by the introduction of charged particles during inhalation. By introducing the charged particles during inhalation and by optimizing the flow rate, tidal volume, and particle size, the targeted deposition in the lung is improved for the best therapeutic aerosols utilization. In addition, the unnecessarily high deposition of toxic particles in the sensitive lung regions can be avoided. Copyright 2012 American Association for Aerosol Research