Skip navigation
  • Home
  • Browse
    • Communities
      & Collections
    • Browse Items by:
    • Publication Date
    • Author
    • Title
    • Subject
    • Department
  • Sign on to:
    • My MacSphere
    • Receive email
      updates
    • Edit Profile


McMaster University Home Page
  1. MacSphere
  2. Open Access Dissertations and Theses Community
  3. Open Access Dissertations and Theses
Please use this identifier to cite or link to this item: http://hdl.handle.net/11375/7215
Title: Determination of the optical properties of two-layer turbid media from spatially resolved reflectance measurements in the frequency domain
Authors: Alexandrakis, George
Advisor: Patterson, M.S.
Department: Medical Physics
Keywords: medical physics
Publication Date: Dec-2000
Abstract: <p>Quantification of the optical properties of superficial biological tissue (e.g. skin on muscle) from spatially resolved reflectance measurements can yield important physiological information. Some examples include the non-invasive measurement of chemotherapy drugs or exogenous chromophores used for photodynamic cancer treatment and the assessment of hemoglobin oxygenation in tissue. Superficial tissue is a multilayered structure with each component having different macroscopic absorption and scattering coefficients, as well as different vascularization and exogenous chromophore pharmacokinetics. A layered model of photon transport is therefore required to match theoretical predictions with experimental measurements. Once a photon transport model is developed, it defines the forward calculation used in the inverse problem of determining the set of tissue optical properties that gives the best fit to experimental data. In the present work the frequency domain (FD) method is employed to probe a two-layer turbid medium. The goal is to improve quantification of superficial tissue optical properties relative to current methods assuming tissue homogeneity. Chapter 2 introduces simulated annealing as a robust method of exploring the limits of a two-layer pure diffusion model in determining the optical properties of a two-layer turbid medium. The inadequacies of pure diffusive transport lead to inaccurate optical property estimates for the top layer. To improve on these estimates a hybrid Monte Carlo (MC)--diffusion model for FD photon transport was developed and presented in Chapter 3. The hybrid model was shown to accurately model MC simulated reflectance data for all optical properties in the physiological range. In Chapter 4 an efficient hybrid simplex--simulated annealing global optimization algorithm was introduced to demonstrate that the hybrid transport model can, in principle, accurately determine all optical properties of a two-layer turbid medium. The practical feasibility of the method was tested with high accuracy FD experimental measurements. Some preliminary results and future directions towards the in vivo implementation of the method are discussed.</p>
URI: http://hdl.handle.net/11375/7215
Identifier: opendissertations/2500
3423
1381974
Appears in Collections:Open Access Dissertations and Theses

Files in This Item:
File SizeFormat 
fulltext.pdf
Open Access
5.75 MBAdobe PDFView/Open
Show full item record Statistics


Items in MacSphere are protected by copyright, with all rights reserved, unless otherwise indicated.

Sherman Centre for Digital Scholarship     McMaster University Libraries
©2022 McMaster University, 1280 Main Street West, Hamilton, Ontario L8S 4L8 | 905-525-9140 | Contact Us | Terms of Use & Privacy Policy | Feedback

Report Accessibility Issue