2000 Progress Report: X-ray CT-based Assessment of Variations in Human Airway Geometry: Implications for Evaluation of Particle Deposition and Dose to Different Populations

EPA Grant Number: R827351C002
Subproject: this is subproject number 002 , established and managed by the Center Director under grant R827351
(EPA does not fund or establish subprojects; EPA awards and manages the overall grant for this center).

Center: EPA NYU PM Center: Health Risks of PM Components
Center Director: N/A
Title: X-ray CT-based Assessment of Variations in Human Airway Geometry: Implications for Evaluation of Particle Deposition and Dose to Different Populations
Investigators: Cohen, Beverly S. , Hoffman, Eric
Institution: New York University School of Medicine , University of Iowa
EPA Project Officer: Chung, Serena
Project Period: June 1, 1999 through May 31, 2005 (Extended to May 31, 2006)
Project Period Covered by this Report: June 1, 2000 through May 31, 2001
RFA: Airborne Particulate Matter (PM) Centers (1999) RFA Text |  Recipients Lists
Research Category: Air Quality and Air Toxics , Particulate Matter , Air

Objective:

Few data are available regarding the regional deposition of particulate matter (PM) in the lungs of people at special risk of environmentally-related lung disease (e.g., those with respiratory diseases, the elderly). The objective of this research project is to investigate the potential for retrieval of morphometric data from three-dimensional images of conducting airways obtained by x-ray computerized tomography (CT), and to explore the potential for the use of stereolithography (STL) to produce hollow airway casts for experimental verification of particle deposition models. This project also will test and validate theoretical and empirical models used to predict detailed particle deposition in living individuals, and ultimately, will allow application of the derived, validated dosimetry models to airways representative of various potentially susceptible subgroups.

Progress Summary:

Rapid prototype processing is necessary to create a physical (solid) model of the segmented airway lumens. Shape-based interpolation was used to create isotropic voxels and to smooth the surface of an airway model. A volumetric rendering of the resultant segmented luminal space of the airway tree phantom was generated utilizing a marching cubes algorithm. Triangular patches divide the cube between regions within the isosurface and regions outside of the airway tree. By connecting the patches from all cubes on the isosurface boundary, we produced a surface representation of airway tree. These triangular patches were converted to the STL file format required by the rapid prototyping device.

The STL unit uses a computer controlled arm connected to a plastic extrusion device to build volumetric structures layer-by-layer. Two heads are present on the machine, one to lay down the plastic compound for the structure of interest and a second head to lay down needed support material for the structure as it is being built and which can later be separated from the structure.

Thin multi-slice helical CT scanning allows the acquisition of high resolution volumetric image data sets of the lung in a breath-hold or at multiple phases within a respiratory cycle. From these scans, hollow airway casts that include 5 or 6 bronchial generations were created and replicated for potential use in studies of inhaled particle deposition.

Future Activities:

In the next year, we will utilize the accomplishments to date, which provided the tools for utilization and retrieval of morphometric data from three-dimensional images of human lung conducting airways obtained by volumetric x-ray. The ultimate goal will be to quantify the impact of airway variability on particulate matter deposition and dose. We will begin to compare inhaled particle deposition pattern and efficiency in vivo in sheep with deposition measured in a hollow airway cast prepared from a three dimensional image of sheep lungs so as to validate the physical model system. We will also explore deposition for a variety of breathing patterns, and when particles are inhaled at different points in the respiratory cycle. We will also begin to examine bolus deposition in vivo in order to validate the hypothesis that regional deposition can be predicted via a mathematical algorithm based on a progressive series of varying-depth bolus deposition measurements.

Journal Articles:

No journal articles submitted with this report: View all 1 publications for this subproject

Supplemental Keywords:

particulate matter, PM, particulate deposition, exposure, computerized tomagraphy, CT, x-ray, human airway, morphometric data, three-dimensional images, stereolithography, volume, sheep., RFA, Health, Scientific Discipline, PHYSICAL ASPECTS, Air, ENVIRONMENTAL MANAGEMENT, particulate matter, Environmental Chemistry, Health Risk Assessment, Risk Assessments, Environmental Monitoring, Physical Processes, Atmospheric Sciences, Risk Assessment, ambient air quality, atmospheric particulate matter, particulates, air toxics, atmospheric particles, chemical characteristics, toxicology, ambient air monitoring, acute lung injury, airborne particulate matter, environmental risks, exposure, epidemelogy, air pollution, aerosol composition, atmospheric aerosol particles, human exposure, PM, X-ray tomagraphy, airway contractile properties, exposure assessment

Progress and Final Reports:

Original Abstract
  • 1999 Progress Report
  • 2001 Progress Report
  • 2002 Progress Report
  • 2003 Progress Report
  • 2004
  • Final Report

  • Main Center Abstract and Reports:

    R827351    EPA NYU PM Center: Health Risks of PM Components

    Subprojects under this Center: (EPA does not fund or establish subprojects; EPA awards and manages the overall grant for this center).
    R827351C001 Exposure Characterization Error
    R827351C002 X-ray CT-based Assessment of Variations in Human Airway Geometry: Implications for Evaluation of Particle Deposition and Dose to Different Populations
    R827351C003 Asthma Susceptibility to PM2.5
    R827351C004 Health Effects of Ambient Air PM in Controlled Human Exposures
    R827351C005 Physicochemical Parameters of Combustion Generated Atmospheres as Determinants of PM Toxicity
    R827351C006 Effects of Particle-Associated Irritants on the Cardiovascular System
    R827351C007 Role of PM-Associated Transition Metals in Exacerbating Infectious Pneumoniae in Exposed Rats
    R827351C008 Immunomodulation by PM: Role of Metal Composition and Pulmonary Phagocyte Iron Status
    R827351C009 Health Risks of Particulate Matter Components: Center Service Core
    R827351C010 Lung Hypoxia as Potential Mechanisms for PM-Induced Health Effects
    R827351C011 Urban PM2.5 Surface Chemistry and Interactions with Bronchoalveolar Lavage Fluid (BALF)
    R827351C012 Subchronic PM2.5 Exposure Study at the NYU PM Center
    R827351C013 Long Term Health Effects of Concentrated Ambient PM2.5
    R827351C014 PM Components and NYC Respiratory and Cardiovascular Morbidity
    R827351C015 Development of a Real-Time Monitoring System for Acidity and Soluble Components in Airborne Particulate Matter
    R827351C016 Automated Real-Time Ambient Fine PM Monitoring System