Texas A&M University LibrariesTexas A&M University LibrariesTexas A&M University Libraries
    • Help
    • Login
    OAKTrust
    View Item 
    •   OAKTrust Home
    • Colleges and Schools
    • Office of Graduate and Professional Studies
    • Electronic Theses, Dissertations, and Records of Study (2002– )
    • View Item
    •   OAKTrust Home
    • Colleges and Schools
    • Office of Graduate and Professional Studies
    • Electronic Theses, Dissertations, and Records of Study (2002– )
    • View Item
    JavaScript is disabled for your browser. Some features of this site may not work without it.

    Design of Optical Skin Phantoms for Reflection Photoplethysmography

    Thumbnail
    View/Open
    BELLOWS-THESIS-2018.pdf (4.414Mb)
    Date
    2018-08-29
    Author
    Bellows, Kevin Robert
    Metadata
    Show full item record
    Abstract
    Optical interrogation of tissues can be used for monitoring physiological parameters, such as heart rate or heart rate variability, or for diagnosis of disease. One such measurement modality is the photoplethysmogram (PPG), which is common in medical settings but has recently become popular in the general population in the form of fitness trackers. Unlike medical devices which use red and near-infrared light to obtain PPGs, wearable electronics predominantly use green illumination. These optical heart rate monitors are not subject to United States Food and Drug Administration (FDA) regulations because they are classified as low-risk general wellness products. This presents an opportunity for products to be released without being sufficiently tested. Optical phantoms provide a means to test optical systems under controlled conditions without the unpredictability that physiology can impart. Physical phantom models of blood and skin soft tissue were made with optical agents mixed into water and polydimethylsiloxane (PDMS), respectively, and characterized. Several optical heart rate monitors intended for fitness tracking then underwent testing by being affixed to a skin soft tissue phantom, which had a hollow channel through which the blood phantom was pumped to emulate pulsatile blood flow. The frequency of the pumping waveform was controlled, and the readings from each monitor were compared to this ground truth. A three-axis motion stage was used to test the monitors’ abilities to reject motion artifact. Differences in performance between the monitors were observed, which further highlighted the need for in vitro testing platforms before sending products to market. A second generation of skin phantoms was designed to account for the cutaneous microvasculature, which plays an important role in a reflection PPG measurement due to green light’s shallow penetration depth in tissue. Anatomical models describing the layers of the skin and their individual blood content values were analyzed using Monte Carlo simulations. Then, a model with a simplified layered geometry was described and simulated to determine if it could yield a comparable response to that of the anatomical models when considering various epidermis tones.
    URI
    http://hdl.handle.net/1969.1/174427
    Subject
    optics
    photoplethysmography
    Monte Carlo simulations
    phantoms
    spectroscopy
    skin
    heart rate monitoring
    in vitro testing
    Collections
    • Electronic Theses, Dissertations, and Records of Study (2002– )
    Citation
    Bellows, Kevin Robert (2018). Design of Optical Skin Phantoms for Reflection Photoplethysmography. Master's thesis, Texas A & M University. Available electronically from http : / /hdl .handle .net /1969 .1 /174427.

    DSpace software copyright © 2002-2016  DuraSpace
    Contact Us | Send Feedback
    Theme by 
    Atmire NV
     

     

    Advanced Search

    Browse

    All of OAKTrustCommunities & CollectionsBy Issue DateAuthorsTitlesSubjectsDepartmentThis CollectionBy Issue DateAuthorsTitlesSubjectsDepartment

    My Account

    LoginRegister

    Statistics

    View Usage Statistics
    Help and Documentation

    DSpace software copyright © 2002-2016  DuraSpace
    Contact Us | Send Feedback
    Theme by 
    Atmire NV