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Proceedings Paper

Analysis of photochemical oxygen consumption effects in photodynamic therapy (Invited Paper)
Author(s): Thomas H. Foster; Scott L. Gibson; Yongli Gao; Russell Hilf
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Paper Abstract

Type II photo-oxidation depends on and consumes oxygen. Several factors, including the concentration of photosensitizer and the radiation fluence rate, determine the rate of oxygen consumption in tissue undergoing Photodynamic Therapy. If the tissue capillary density is sparse, as it is in many human tumors, our calculations indicate that for cells sufficiently distant from the nearest capillary, fluence rates commonly used in PDT (50 - 200 mW/cm2) deplete 3O2 levels below those necessary for 1O2 formation. The calculations suggest that under these conditions reduced fluence rates and radiation dose fractionation should be more effective than continuous radiation at high fluence rates in producing 1O2 throughout the treated tissue volume. These predictions are supported by results obtained in vivo. The data and their interpretation have implications for PDT dosimetry and offer the possibility of improved therapeutic ratio.

Paper Details

Date Published: 1 June 1992
PDF: 11 pages
Proc. SPIE 1645, Optical Methods for Tumor Treatment and Detection: Mechanisms and Techniques in Photodynamic Therapy, (1 June 1992); doi: 10.1117/12.60933
Show Author Affiliations
Thomas H. Foster, Univ. of Rochester School of Medicine and Dentistry (United States)
Scott L. Gibson, Univ. of Rochester School of Medicine and Dentistry (United States)
Yongli Gao, Univ. of Rochester (United States)
Russell Hilf, Univ. of Rochester School of Medicine and Dentistry (United States)


Published in SPIE Proceedings Vol. 1645:
Optical Methods for Tumor Treatment and Detection: Mechanisms and Techniques in Photodynamic Therapy
Thomas J. Dougherty, Editor(s)

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