Visualization of local deposition of nebulized aerosols in a human upper respiratory tract model

Xi, Jinxiang; Yang, Tiancheng; Talaat, Khaled; Wen, Tianshu; Klozik, Scott; Peters, Shannon

doi:10.1007/s12650-017-0456-0

Cited by 23 publications

(14 citation statements)

References 53 publications

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“…When aerosol particles are inhaled, a fraction of the inhaled particles deposit in the respiratory tract, while the rest is exhaled out 5–9 . The deposition fraction is dependent on many parameters such as the geometry of the respiratory airways, the particle size of the inhaled aerosol, and the breathing condition 10,11 . Inhaled radioactive aerosols can expose internal organs to radiation for extended periods and may induce a spectrum of functional and morphological changes, such as genetic mutations and carcinogenesis 12,13 .…”

Section: Introductionmentioning

confidence: 99%

Radiation Dosimetry of Inhaled Radioactive Aerosols: CFPD and MCNP Transport Simulations of Radionuclides in the Lung

Talaat

Baldez

et al. 2019

Sci Rep

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Despite extensive efforts in studying radioactive aerosols, including the transmission of radionuclides in different chemical matrices throughout the body, the internal organ-specific radiation dose due to inhaled radioactive aerosols has largely relied on experimental deposition data and simplified human phantoms. Computational fluid-particle dynamics (CFPD) has proven to be a reliable tool in characterizing aerosol transport in the upper airways, while Monte Carlo based radiation codes allow accurate simulation of radiation transport. The objective of this study is to numerically assess the radiation dosimetry due to particles decaying in the respiratory tract from environmental radioactive exposures by coupling CFPD with Monte Carlo N-Particle code, version 6 (MCNP6). A physiologically realistic mouth-lung model extending to the bifurcation generation G9 was used to simulate airflow and particle transport within the respiratory tract. Polydisperse aerosols with different distributions were considered, and deposition distribution of the inhaled aerosols on the internal airway walls was quantified. The deposition mapping of radioactive aerosols was then registered to the respiratory tract of an image-based whole-body adult male model (VIP-Man) to simulate radiation transport and energy deposition. computer codes were developed for geometry visualization, spatial normalization, and source card definition in MCNP6. Spatial distributions of internal radiation dosimetry were compared for different radionuclides (131 i, 134,137 cs, 90 Sr-90 Y, 103 Ru and 239,240 Pu) in terms of the radiation fluence, energy deposition density, and dose per decay. Radioactive aerosols arise from various sources such as nuclear accidents, natural decay processes, and the decommissioning of nuclear reactors 1-3. Highly radioactive micro-particles were released to the surrounding environment in the Chernobyl and Fukushima Daiichi accidents 1,4. The aerosol particles released from accidents and natural decay processes may remain suspended in the air for extended periods, be incorporated into soil particles that can reenter the air, or be inhaled by humans or animals. When aerosol particles are inhaled, a fraction of the inhaled particles deposit in the respiratory tract, while the rest is exhaled out 5-9. The deposition fraction is dependent on many parameters such as the geometry of the respiratory airways, the particle size of the inhaled aerosol, and the breathing condition 10,11. Inhaled radioactive aerosols can expose internal organs to radiation for extended periods and may induce a spectrum of functional and morphological changes, such as genetic mutations and carcinogenesis 12,13. Their severity can be related to the absorbed radiation dose in the different specific tissues, which is further related to the number of radioactive particles inhaled, how long they stay, and the type of radiation they emit. Unlike fat and muscles being the main internal defense to external exposures, there is nothing to protect cells and tissues of sus...

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Section: Introductionmentioning

confidence: 99%

Radiation Dosimetry of Inhaled Radioactive Aerosols: CFPD and MCNP Transport Simulations of Radionuclides in the Lung

Talaat

Baldez

et al. 2019

Sci Rep

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“…However, there is a lack of understanding in light of the behavior and fate of inhaled agents (viruses or bio-aerosols) in the respiratory tract of rabbits. Moreover, local dosimetry is a more relevant factor to assess outcomes than the total and sub-regional deposition rates [5][6][7]. To reliably predict both the total and local deposition rates becomes the critical first step to quantify the dose-response relationship, which further requires the detailed knowledge of the nasal physiology and flow dynamics within it [8][9][10].…”

Section: Introductionmentioning

confidence: 99%

Ventilation Modulation and Nanoparticle Deposition in Respiratory and Olfactory Regions of Rabbit Nose

Talaat

et al. 2019

Animals

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The rabbit nose’s ability to filter out inhaled agents is directly related to its defense to infectious diseases. The knowledge of the rabbit nose anatomy is essential to appreciate its functions in ventilation regulation, aerosol filtration and olfaction. The objective of this study is to numerically simulate the inhalation and deposition of nanoparticles in a New Zealand white (NZW) rabbit nose model with an emphasis on the structure–function relation under normal and sniffing conditions. To simulate the sniffing scenario, the original nose model was modified to generate new models with enlarged nostrils or vestibules based on video images of a rabbit sniffing. Ventilations into the maxilloturbinate and olfactory region were quantified with varying nostril openings, and deposition rates of inhaled aerosols ranging from 0.5 nm to 1000 nm were characterized on the total, sub-regional and local basis. Results showed that particles which deposited in the olfactory region came from a specific area in the nostril. The spiral vestibule played an essential role in regulating flow resistance and flow partition into different parts of the nose. Increased olfactory doses were persistently predicted in models with expanded nostrils or vestibule. Particles in the range of 5–50 nm are more sensitive to the geometry variation than other nanoparticles. It was also observed that exhaled aerosols occupy only the central region of the nostril, which minimized the mixing with the aerosols close to the nostril wall, and potentially allowed the undisruptive sampling of odorants. The results of this study shed new light on the ventilation regulation and inhalation dosimetry in the rabbit nose, which can be further implemented to studies of infectious diseases and immunology in rabbits.

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“…However, experimental studies into particle deposition in actual airways have been limited due to several regulatory and safety concerns. Visualization studies using imaging technology are also required to obtain details regarding the particle transport deposition in actual airways, with particle image velocimetry being employed to evaluate the particle behaviour and the deposition of DPI formulations …”

Section: Introductionmentioning

confidence: 99%

“…Visualization studies using imaging technology are also required to obtain details regarding the particle transport deposition in actual airways, with particle image velocimetry being employed to evaluate the particle behaviour and the deposition of DPI formulations. [15,16] Numerical simulations including computational fluid dynamics (CFD) have been applied to understand the behaviour of drugs in actual human airways. [17][18][19][20] CFD is emerging as a powerful tool for describing and visualizing particle transport in dispersed-phase flows, [21] and significant efforts have been made in terms of numerical simulations to determine the deposition efficiencies from DPI devices.…”

Section: Introductionmentioning

confidence: 99%

Numerical simulations of particle behaviour in a realistic human airway model with varying inhalation patterns

et al. 2019

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Objectives For dry powder inhalers, the airflow properties in the airways could affect the deposition of inhaled particles; the flow patterns vary inherently between patients. This paper provides an evaluation of the effects of six airflow patterns on the behaviour of inhaled particles, as determined by using numerical simulations. Methods Constant‐velocity and unsteady inhalation flows were employed. The unsteady inhalation flow was set as an inhalation curve with a peak inspiratory flow rate. Under a constant flow of 28.3 l/min, the total flow rates were calculated to confirm the validity of the numerical simulation. The effects of different inhalation patterns on the particle behaviour in a realistic human airway model were revealed via numerical simulation. Key findings Different flow rates affected the behaviour and deposition of the inhaled particles. Under an inhalation flow pattern, different airflow tendencies were observed between the right and left bronchi. Particle deposition in the airways was promoted by a vortex following terminal‐velocity‐like breath‐holding. The inhalation flow pattern affected the behaviour and deposition of inhaled particles in the airway. Conclusions Our results indicated that particle deposition in a realistic human airway model was promoted by a vortex formation following the terminal‐velocity‐like breath‐holding. Moreover, the inhalation flow pattern significantly influenced the behaviour and deposition of inhaled particles in the airways. Additionally, the effect of flow patterns on the particle deposition in each airway position was quantitatively evaluated by numerical simulations for a realistic human airway model.

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Visualization of local deposition of nebulized aerosols in a human upper respiratory tract model

Cited by 23 publications

References 53 publications

Radiation Dosimetry of Inhaled Radioactive Aerosols: CFPD and MCNP Transport Simulations of Radionuclides in the Lung

Radiation Dosimetry of Inhaled Radioactive Aerosols: CFPD and MCNP Transport Simulations of Radionuclides in the Lung

Ventilation Modulation and Nanoparticle Deposition in Respiratory and Olfactory Regions of Rabbit Nose

Numerical simulations of particle behaviour in a realistic human airway model with varying inhalation patterns

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