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RECONSTRUCTION OF HUMAN LUNG MORPHOLOGY MODELS FROM MAGNETIC RESONANCE IMAGES
Citation:
Martonen, T B. AND K K. Isaacs. RECONSTRUCTION OF HUMAN LUNG MORPHOLOGY MODELS FROM MAGNETIC RESONANCE IMAGES. Presented at US-Japan Symp. on Drug Delivery Sytems, Lahaina, Maui, Hawaii, December 14-19, 2003.
Description:
Reconstruction of Human Lung Morphology Models from Magnetic Resonance Images
T. B. Martonen (Experimental Toxicology Division, U.S. EPA, Research Triangle Park, NC 27709) and K. K. Isaacs (School of Public Health, University of North Carolina, Chapel Hill, NC 27514)
To assess the threat to human health presented by airborne particulate matter (PM), it is necessary to know the deposition patterns of inhaled pollutants. Of special importance to the EPA are sensitive subpopulations, namely children and individuals suffering from respiratory diseases such as asthma and chronic obstructive pulmonary disease (COPD). A biologically realistic PM dosimetry model will provide the EPA with a scientific foundation from which to determine federal regulatory standards. As a first step in modeling the risk assessment process, a description of lung morphological structures as a function of age and disease is necessary for modeling the deposition and fate of inhaled PM. Adult subjects were first addressed and a morphological model of the lung boundary for an subject was generated from magnetic resonance (MR) images. Data visualization software was used to reconstruct the lung volume of a subject from a series of transverse MR images collected at many different vertical locations in lungs, ranging from apex to base. The model was based on data published in the peer-reviewed literature and already in the public domain. The morphological lung model was then built using isosurface extraction techniques. An original computer code was written to describe the respiratory anatomy of the subject. The lung model provides a flexible geometric description of the lung boundary to be used in conjunction with a branching airway network algorithm to build an anatomically realistic model of the airway tree. The model will be the seminal component of an EPA health effects algorithm for inhaled PM such as secondary cigarette smoke, sulfuric acid from emissions, diesel exhaust, and aerobiological elements such as anthrax. This information will facilitate the creation of customized morphological models for individual subjects, resulting in improved interpretation of PM distribution data obtained from single photon emission computed tomography (SPECT) studies. Therefore, the PM dose delivered to airway cells and tissue can be quantitated, permitting EPA risk assessment to be placed on an objective basis because factors identifying the deposition of inhaled particles within the human respiratory system are clearly identified and formulated. Disclaimer: This is an abstract of a proposed presentation and does not necessarily reflect EPA policy.