Light dosimetry technique for endoscopic PDT using microlens optical fiber

Steven Jacques

Research output: Chapter in Book/Report/Conference proceedingChapter

Abstract

A simple procedure is presented for determining the irradiance of light striking tissues during light delivery using a microlens optical fiber via an endoscope. The particular example is photodynamic therapy (PDT) of laryngeal cancer. A microlens optical fiber is an optical fiber with a small lens assembly at its terminus which magnifies the image of the end of the fiber yielding a uniform irradiance in a plane distant from the fiber. Prior to the therapy, the relation between fiber-target distance, h [cm], and the diameter of the uniform beam, d(h) [cm], was established and the area of the beam was calculated: A(h) = πd(h)2/4. The laser power P [W] required to achieve a desired irradiance E [W/cm2] was P(h) = EA(h), and this relation was prepared as a simple graph for routine use in the clinic. During the therapy, the doctor advances the optical fiber through the working channel of the endoscope to touch the target tissue site while observing through the optical channel, and marks the fiber on the outside of the endoscope. The doctor then retracts the fiber until an aiming beam transmitted through the fiber fully illuminates the desired target area, and again marks the fiber on the outside of the endoscope. The difference in the two marks on the fiber outside the endoscope yields h, the height of the fiber above the target tissue. The laser operator then uses the P(h) = EA(h) graph to select the proper laser power to achieve the desired E. Although trivially simple, this dosimetry procedure was critical to the proper implementation of PDT for laryngeal cancer.

Original languageEnglish (US)
Title of host publicationProceedings of SPIE - The International Society for Optical Engineering
PublisherSociety of Photo-Optical Instrumentation Engineers
Pages455-462
Number of pages8
Volume3601
StatePublished - 1999
EventProceedings of the 1999 Laser-Tissue Interaction X: Photochemical, Photothermal, and Photomechanical - San Jose, CA, USA
Duration: Jan 24 1999Jan 27 1999

Other

OtherProceedings of the 1999 Laser-Tissue Interaction X: Photochemical, Photothermal, and Photomechanical
CitySan Jose, CA, USA
Period1/24/991/27/99

Fingerprint

Photodynamic therapy
Dosimetry
dosimeters
Optical fibers
therapy
optical fibers
endoscopes
Endoscopy
fibers
Fibers
irradiance
Tissue
Lasers
cancer
lasers
touch
Lenses
delivery
assembly
lenses

ASJC Scopus subject areas

  • Electrical and Electronic Engineering
  • Condensed Matter Physics

Cite this

Jacques, S. (1999). Light dosimetry technique for endoscopic PDT using microlens optical fiber. In Proceedings of SPIE - The International Society for Optical Engineering (Vol. 3601, pp. 455-462). Society of Photo-Optical Instrumentation Engineers.

Light dosimetry technique for endoscopic PDT using microlens optical fiber. / Jacques, Steven.

Proceedings of SPIE - The International Society for Optical Engineering. Vol. 3601 Society of Photo-Optical Instrumentation Engineers, 1999. p. 455-462.

Research output: Chapter in Book/Report/Conference proceedingChapter

Jacques, S 1999, Light dosimetry technique for endoscopic PDT using microlens optical fiber. in Proceedings of SPIE - The International Society for Optical Engineering. vol. 3601, Society of Photo-Optical Instrumentation Engineers, pp. 455-462, Proceedings of the 1999 Laser-Tissue Interaction X: Photochemical, Photothermal, and Photomechanical, San Jose, CA, USA, 1/24/99.
Jacques S. Light dosimetry technique for endoscopic PDT using microlens optical fiber. In Proceedings of SPIE - The International Society for Optical Engineering. Vol. 3601. Society of Photo-Optical Instrumentation Engineers. 1999. p. 455-462
Jacques, Steven. / Light dosimetry technique for endoscopic PDT using microlens optical fiber. Proceedings of SPIE - The International Society for Optical Engineering. Vol. 3601 Society of Photo-Optical Instrumentation Engineers, 1999. pp. 455-462
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