Light dosimetry calculations for esophageal photodynamic therapy using porfimer sodium

Linda R. Jones, Norris W. Preyer, Monica A. Davis, Carson Grimes, Kristie Edling, Nicholas Holdgate, Michael B. Wallace, Herbert C. Wolfsen

Research output: Chapter in Book/Report/Conference proceedingConference contribution

2 Scopus citations

Abstract

Background: Photodynamic therapy using porfimer sodium (Ps-PDT) is approved for use in patients with Barrett's high-grade 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. Wavelength Tissue μ eff μ a μ s' (nm) type mm -1 mm -1 mm -1 630 mucosa 0.522 0.068 1.27 630 Muscle layer 0.521 0.109 0.722 630 Whole esophagus 0.482 0.061 1.21 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.

Original languageEnglish (US)
Title of host publicationOptical Methods for Tumor Treatment and Detection
Subtitle of host publicationMechanisms and Techniques in Photodynamic Therapy XV
DOIs
StatePublished - Jun 30 2006
EventOptical Methods for Tumor Treatment and Detection: Mechanisms and Techniques in Photodynamic Therapy XV - San Jose, CA, United States
Duration: Jan 21 2006Jan 22 2006

Publication series

NameProgress in Biomedical Optics and Imaging - Proceedings of SPIE
Volume6139
ISSN (Print)1605-7422

Other

OtherOptical Methods for Tumor Treatment and Detection: Mechanisms and Techniques in Photodynamic Therapy XV
CountryUnited States
CitySan Jose, CA
Period1/21/061/22/06

Keywords

  • Barrett's esophagus
  • Light dosimetry
  • Photodynamic therapy

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Biomaterials
  • Atomic and Molecular Physics, and Optics
  • Radiology Nuclear Medicine and imaging

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    Jones, L. R., Preyer, N. W., Davis, M. A., Grimes, C., Edling, K., Holdgate, N., Wallace, M. B., & Wolfsen, H. C. (2006). Light dosimetry calculations for esophageal photodynamic therapy using porfimer sodium. In Optical Methods for Tumor Treatment and Detection: Mechanisms and Techniques in Photodynamic Therapy XV [61391D] (Progress in Biomedical Optics and Imaging - Proceedings of SPIE; Vol. 6139). https://doi.org/10.1117/12.660155