{"id":{"repo_id":"unlv","oai_identifier":"oai:oasis.library.unlv.edu:rtds-2553"},"canonical_url":"https://search.dev.ndltd.org/etd/unlv/oai:oasis.library.unlv.edu:rtds-2553","repository":{"repo_id":"unlv","name":"University of Nevada - Las Vegas","base_url":"https://oasis.library.unlv.edu/do/oai/"},"display":{"title":"Investigation of different light delivery schemes in photodynamic therapy of human glioma spheroids","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.).","abstract_html":"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.).","abstract_has_math":false,"creators":["Rodenbush, Robin Marie"],"institution":"University of Nevada, Las Vegas","degree_name":"Master of Science (MS)","degree_level":"Thesis","degree_discipline":"Health Physics and Diagnostic Sciences","degree_department":null,"school":null,"contributors":["Steen Madsen"],"advisors":[],"committee_chairs":[],"committee_members":[],"year":2003,"date_issued":"2003-01-01T08:00:00Z","date_published":"2003-01-01T08:00:00Z","updated_at":"2026-07-24T05:25:40Z","subjects":[],"languages":["English"],"rights":["IN COPYRIGHT. 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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.)."]},{"key":"dc:format","label":"Dc Format","values":["pdf"]},{"key":"dc:title","label":"Title","values":["Investigation of different light delivery schemes in photodynamic therapy of human glioma spheroids"]}]}],"canonical_facts":{"dc:contributor":["Steen Madsen"],"dc:creator":["Rodenbush, Robin Marie"],"dc:description.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.)."],"dc:format":["pdf"],"dc:identifier":["10.25669/c451-y4wz","https://oasis.library.unlv.edu/rtds/1554","https://oasis.library.unlv.edu/context/rtds/article/2553/viewcontent/uc.pdf"],"dc:language":["English"],"dc:publisher":["University of Nevada, Las Vegas"],"dc:rights":["IN COPYRIGHT. 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