• Login
    View Item 
    •   Home
    • UA Graduate and Undergraduate Research
    • UA Theses and Dissertations
    • Dissertations
    • View Item
    •   Home
    • UA Graduate and Undergraduate Research
    • UA Theses and Dissertations
    • Dissertations
    • View Item
    JavaScript is disabled for your browser. Some features of this site may not work without it.

    Browse

    All of UA Campus RepositoryCommunitiesTitleAuthorsIssue DateSubmit DateSubjectsPublisherJournalThis CollectionTitleAuthorsIssue DateSubmit DateSubjectsPublisherJournal

    My Account

    LoginRegister

    About

    AboutUA Faculty PublicationsUA DissertationsUA Master's ThesesUA Honors ThesesUA PressUA YearbooksUA CatalogsUA Libraries

    Statistics

    Most Popular ItemsStatistics by CountryMost Popular Authors

    Application of control theory to the hyperthermia problem.

    • CSV
    • RefMan
    • EndNote
    • BibTex
    • RefWorks
    Thumbnail
    Name:
    azu_td_9307663_sip1_c.pdf
    Size:
    4.737Mb
    Format:
    PDF
    Download
    Author
    Potocki, Jon Kyle.
    Issue Date
    1992
    Keywords
    Dissertations, Academic.
    System theory.
    Electrical engineering.
    Control theory.
    Committee Chair
    Tharp, H.S.
    
    Metadata
    Show full item record
    Publisher
    The University of Arizona.
    Rights
    Copyright © is held by the author. Digital access to this material is made possible by the University Libraries, University of Arizona. Further transmission, reproduction or presentation (such as public display or performance) of protected items is prohibited except with permission of the author.
    Abstract
    The objective of a hyperthermia cancer treatment is to heat the tumor tissue to a therapeutic level while limiting the detrimental effects experienced by the surrounding normal tissue. To achieve an optimal treatment requires knowledge of the resulting temperature response and an understanding of the complex interaction between the thermal response, the applied power, and the blood flow in the target tissue region. This dissertation considers model reduction to overcome the large dimensions associated with thermal modelling, extended Kalman filtering to estimate both the unmeasured temperature states and the unknown blood perfusion magnitudes, optimization of the applied power to achieve the best thermal response, and optimal servomechanism control to attain the desired regulated output tracking. A controller methodology that combines thermal estimation, applied power optimization, and optimal servomechanism control with a simple expert system shell is examined. This controller methodology is analyzed for a simulated scanned focussed ultrasound system (SFUS) based upon the bioheat transfer equation (BHTE) model of the thermal response in the target region. The results of the presented studies illustrate the following important points. First, open-loop reduced-order models based on the balanced transformation provide drastic model reduction for controller design purposes. Second, the success of thermal estimation depends on the number and the location of the thermal sensors, and the accuracy of the modelled blood perfusion profile. Third, multiple modelling in estimation provides an alternate technique for overcoming model mismatch associated with the modelling of the blood perfusion pattern. Fourth, the choice of the set points for the optimal servomechanism controller play a crucial role in the resulting tissue temperatures. Fifth, the scan parameter sets that result in optimal SFUS power profiles need to be changed on-line during a treatment as the blood perfusion magnitude and pattern are estimated. Finally, to fully automate a hyperthermia treatment requires that the expertise of the clinician be incorporated into the controller design. Hierarchical control provides a means of incorporating the expert system shell at the higher levels of the controller, while maintaining optimal servomechanism control at the lower levels.
    Type
    text
    Dissertation-Reproduction (electronic)
    Degree Name
    Ph.D.
    Degree Level
    doctoral
    Degree Program
    Electrical and Computer Engineering
    Graduate College
    Degree Grantor
    University of Arizona
    Collections
    Dissertations

    entitlement

     
    The University of Arizona Libraries | 1510 E. University Blvd. | Tucson, AZ 85721-0055
    Tel 520-621-6442 | repository@u.library.arizona.edu
    DSpace software copyright © 2002-2017  DuraSpace
    Quick Guide | Contact Us | Send Feedback
    Open Repository is a service operated by 
    Atmire NV
     

    Export search results

    The export option will allow you to export the current search results of the entered query to a file. Different formats are available for download. To export the items, click on the button corresponding with the preferred download format.

    By default, clicking on the export buttons will result in a download of the allowed maximum amount of items.

    To select a subset of the search results, click "Selective Export" button and make a selection of the items you want to export. The amount of items that can be exported at once is similarly restricted as the full export.

    After making a selection, click one of the export format buttons. The amount of items that will be exported is indicated in the bubble next to export format.