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Proceedings Paper

Light dosimetry calculations for esophageal photodynamic therapy using porfimer sodium
Author(s): Linda R. Jones; Norris W. Preyer Jr.; Monica A. Davis; Carson Grimes; Kristie Edling; Nicholas Holdgate; Michael B. Wallace; Herbert C. Wolfsen
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Paper Abstract

Background: Photodynamic therapy using porfimer sodium (Ps-PDT) is approved for use in patients with Barrett's highgrade dysplasia and esophageal carcinoma. Ps-PDT light dosimetry, however, is critically important to treatment outcomes since insufficient ablation results in residual dysplasia and carcinoma while excessive treatment results in stricture formation. Aim: The aim of this study was to model esophageal PDT with optical absorption and scattering coefficients derived from an ex-vivo porcine multilayer esophagus model. Methods: Optical coefficients were derived for the mucosal and muscle layers of normal pig esophagus. The mucosal layer (mucosa, muscularis mucosa and submucosa) was separated from the muscle layer. Diffuse reflectance and transmittance were measured with an integrating sphere spectrophotometer. Absorption and reduced scattering coefficients were determined with the inverse adding doubling method. (Table not available in abstract, see pdf of paper) Multilayer Monte Carlo simulation and single-layer mathematical dosimetry equations were employed to model esophageal PDT with the derived coefficients. Porfimer sodium addition was modeled with an increase in both absorption and scattering. Depth of injury, assumed to require a threshold light dose, was estimated for various light doses commonly used in clinical practice. Depth of injury was then compared to clinical outcomes reported in the literature for various light doses.

Paper Details

Date Published: 6 March 2006
PDF: 10 pages
Proc. SPIE 6139, Optical Methods for Tumor Treatment and Detection: Mechanisms and Techniques in Photodynamic Therapy XV, 61391D (6 March 2006); doi: 10.1117/12.660155
Show Author Affiliations
Linda R. Jones, College of Charleston (United States)
Norris W. Preyer Jr., College of Charleston (United States)
Monica A. Davis, College of Charleston (United States)
Carson Grimes, College of Charleston (United States)
Kristie Edling, College of Charleston (United States)
Nicholas Holdgate, College of Charleston (United States)
Michael B. Wallace, Mayo Clinic (United States)
Herbert C. Wolfsen, Mayo Clinic (United States)

Published in SPIE Proceedings Vol. 6139:
Optical Methods for Tumor Treatment and Detection: Mechanisms and Techniques in Photodynamic Therapy XV
David Kessel, Editor(s)

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