• About
    • Login
    View Item 
    •   Institutional Repository Home
    • Electronic Theses and Dissertations
    • Electronic Theses and Dissertations
    • View Item
    •   Institutional Repository Home
    • Electronic Theses and Dissertations
    • Electronic Theses and Dissertations
    • View Item
    JavaScript is disabled for your browser. Some features of this site may not work without it.

    Browse

    All of Institutional RepositoryCommunities & CollectionsBy Issue DateAuthorsTitlesSubjectsDepartmentThis CollectionBy Issue DateAuthorsTitlesSubjectsDepartment

    My Account

    LoginRegister

    The effect of pulse structure on soft tissue laser ablation at mid-infrared wavelengths

    Mackanos, Mark Andrew
    : https://etd.library.vanderbilt.edu/etd-11292004-165251
    http://hdl.handle.net/1803/14855
    : 2004-11-30

    Abstract

    BIOMEDICAL ENGINEERING THE EFFECT OF PULSE STRUCTURE ON SOFT TISSUE LASER ABLATION AT MID-INFRARED WAVELENGTHS MARK ANDREW MACKANOS Dissertation under the direction of Professor E. Duco Jansen A series of experimental investigations have demonstrated that targeting a mid-infrared Mark-III Free-Electron Laser to wavelengths near 6.45 ƒÝm results in tissue ablation with minimal collateral damage and substantial efficiency useful for human surgery. Thermodynamic reasoning suggests that the minimal collateral damage at this wavelength is due to the differential absorption of protein and water; which causes compromised tissue integrity by laser heating of the non-aqueous components prior to explosive vaporization. These properties are advantageous for surgery because they reduce the structural integrity of the tissue, thus reducing amount of energy needed for ablation. While the FEL, based on these findings, has been used successfully in eight human surgeries to date, it is unlikely that this laser will become broadly used clinically due to its expense and difficult implementation. Recent developments in conventional laser technology have provided access to this wavelength. While the average and peak power of these sources are still not equivalent to the FEL, recent data indicates that ablation studies are feasible. The research described here investigates the role of pulse structure with regards to soft tissue ablation to determine the feasibility of these sources as potential FEL replacements for clinical applications. Relevant parameters including the threshold radiant exposure and ablated crater depth were studied for comparison of the native FEL micropulse with a stretched FEL micropulse and a ZnGeP2 OPO. Brightfield imaging was used to analyze the effect of pulse structure on the dynamics of ablation, while histology on cornea and dermis was performed to study pulse effects on thermal damage. Mass spectrometry was also used to investigate whether non-linear effects are involved with the FEL micropulse in changing the chemical structure of proteins prior to ablation. The results of this analysis show that the micropulse structure of the FEL does not play a role in the efficient ablation of soft tissue with minimal collateral damage that has been shown previously, and alternative sources remain viable alternatives to the FEL.
    Show full item record

    Files in this item

    Icon
    Name:
    mackanos.pdf
    Size:
    6.398Mb
    Format:
    PDF
    View/Open

    This item appears in the following collection(s):

    • Electronic Theses and Dissertations

    Connect with Vanderbilt Libraries

    Your Vanderbilt

    • Alumni
    • Current Students
    • Faculty & Staff
    • International Students
    • Media
    • Parents & Family
    • Prospective Students
    • Researchers
    • Sports Fans
    • Visitors & Neighbors

    Support the Jean and Alexander Heard Libraries

    Support the Library...Give Now

    Gifts to the Libraries support the learning and research needs of the entire Vanderbilt community. Learn more about giving to the Libraries.

    Become a Friend of the Libraries

    Quick Links

    • Hours
    • About
    • Employment
    • Staff Directory
    • Accessibility Services
    • Contact
    • Vanderbilt Home
    • Privacy Policy