Optics of light dosimetry for PDT in superficial lesions versus bulky tumors

Steven Jacques

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

9 Citations (Scopus)

Abstract

The light dosimetry for photodynamic therapy (PDT) for superficial lesions is concerned with ensuring sufficient light in the superficial tissue layer to achieve efficacious PDT. The light dosimetry for bulky tumors is concerned with the maximum depth of effective treatment while expecting over exposure of the tumor surface. The light delivered to a tissue surface does not equal the light received by the superficial region of that tissue. Backscattered light from the underlying tissues augments the surface irradiance to yield a higher fluence rate (W/cm2) in the target superficial tissue layer. The effective irradiance of treatment light, E [W/cm2], seen by a superficial lesion is approximated: E = Eo(1 + 2R(1 + ri)/(1 - ri)) = Eo(1 + 6R) where Eo is the irradiance delivered to the surface, R is the fraction of incident light that escapes the tissue as observable reflectance (typically about 0.30-0.60), and ri is the total internal reflection of light attempting to escape at the air/tissue surface (about 0.50). Hence the factor (1 + 6R) varies from 2.8-4.6. The backscattered light significantly affects the treatment light dose for superficial lesions. The light within a bulky tumor is approximated: E = Eo k exp(-z/delta), where z is the depth in the tissue, k is a backscatter term, k = 3 + 5.1R - 2exp(- 9.7R) (eg., k = 4.1-5.9 for R = 0.30-0.60), and delta is the 1/e optical penetration depth (typically about 0.3-0.5 cm).

Original languageEnglish (US)
Title of host publicationProceedings of SPIE - The International Society for Optical Engineering
EditorsT.J. Dougherty
Pages59-68
Number of pages10
Volume4612
DOIs
StatePublished - 2002
EventOptical Methods for Tumor Treatment and Detection: Mechanisms and Techniques in Photodynamic Therapy XI - San Jose, CA, United States
Duration: Jan 19 2002Jan 20 2002

Other

OtherOptical Methods for Tumor Treatment and Detection: Mechanisms and Techniques in Photodynamic Therapy XI
CountryUnited States
CitySan Jose, CA
Period1/19/021/20/02

Fingerprint

Photodynamic therapy
lesions
Dosimetry
dosimeters
Tumors
therapy
Optics
tumors
optics
Tissue
irradiance
escape
fluence
penetration

Keywords

  • Biomedical optics
  • Optical dosimetry
  • PDT
  • Photodynamic therapy

ASJC Scopus subject areas

  • Electrical and Electronic Engineering
  • Condensed Matter Physics

Cite this

Jacques, S. (2002). Optics of light dosimetry for PDT in superficial lesions versus bulky tumors. In T. J. Dougherty (Ed.), Proceedings of SPIE - The International Society for Optical Engineering (Vol. 4612, pp. 59-68) https://doi.org/10.1117/12.469332

Optics of light dosimetry for PDT in superficial lesions versus bulky tumors. / Jacques, Steven.

Proceedings of SPIE - The International Society for Optical Engineering. ed. / T.J. Dougherty. Vol. 4612 2002. p. 59-68.

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

Jacques, S 2002, Optics of light dosimetry for PDT in superficial lesions versus bulky tumors. in TJ Dougherty (ed.), Proceedings of SPIE - The International Society for Optical Engineering. vol. 4612, pp. 59-68, Optical Methods for Tumor Treatment and Detection: Mechanisms and Techniques in Photodynamic Therapy XI, San Jose, CA, United States, 1/19/02. https://doi.org/10.1117/12.469332
Jacques S. Optics of light dosimetry for PDT in superficial lesions versus bulky tumors. In Dougherty TJ, editor, Proceedings of SPIE - The International Society for Optical Engineering. Vol. 4612. 2002. p. 59-68 https://doi.org/10.1117/12.469332
Jacques, Steven. / Optics of light dosimetry for PDT in superficial lesions versus bulky tumors. Proceedings of SPIE - The International Society for Optical Engineering. editor / T.J. Dougherty. Vol. 4612 2002. pp. 59-68
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