Award Date
1-1-2003
Degree Type
Thesis
Degree Name
Master of Science (MS)
Department
Health Physics and Diagnostic Sciences
First Committee Member
Steen Madsen
Number of Pages
46
Abstract
The response of human glioma spheroids to ALA-mediated photodynamic therapy subjected to various optical dose delivery schemes is investigated. In particular, the effects of fluence, fluence rate, light dose fractionation and long-term repeat PDT is considered. Improved PDT response was found for low fluence rate photodynamic treatments i.e. those at or below 25 mW cm-2 . Results are consistent with the self-sensitized singlet oxygen mediated photobleaching model of Georgakoudi et al (Georgakoudi, 1998., in which the response is attributed to the deposition of singlet oxygen to a larger volume, i.e., deeper into the spheroid. The efficacy of high-fluence rate PDT (150 mW cm-2) can be improved by the introduction of dark intervals---an approximately 35% enhanced spheroid response was observed with cyclic intervals of between 15 and 45 s. Shorter on/off cycles appear more effective than longer cycles; Repetitive PDT consisting of multiple weekly treatments at sub-optimal fluences (12.5 or 25 J cm-2) revealed marked improvements in efficacy. (Abstract shortened by UMI.).
Keywords
Delivery; Glioma; Human; Investigation; Light; Photodynamic; Schemes; Spheroids; Therapy
Controlled Subject
Medicine; Radiation; Nuclear physics; Oncology; Diagnostic imaging
File Format
File Size
2201.6 KB
Degree Grantor
University of Nevada, Las Vegas
Language
English
Permissions
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Repository Citation
Rodenbush, Robin Marie, "Investigation of different light delivery schemes in photodynamic therapy of human glioma spheroids" (2003). UNLV Retrospective Theses & Dissertations. 1554.
http://dx.doi.org/10.25669/c451-y4wz
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