Cooperative phenomena in two-pulse, two-color laser photocoagulation of cutaneous blood vessels

John F. Black, Jennifer Kehiet Barton, George Frangineas, Herbert Pummer

Research output: Contribution to journalArticle

9 Scopus citations

Abstract

A novel laser system has been developed to study the effects of multiple laser pulses of differing wavelengths on cutaneous blood vessels in vivo, using the hamster dorsal skin flap preparation. The system permits sequenced irradiation with well-defined intrapulse spacing at 532 nm, using a long pulse frequency doubled Nd:YAG laser, and at 1064 nm, using a long pulse Nd:YAG laser. Using this system, we have identified a parameter space where two pulses of different wavelengths act in a synergistic manner to effect permanent vessel damage at radiant exposures where the two pulses individually have little or no effect. Using a two-color pump-probe technique in vitro, we have identified a phenomenon we call green-light-induced infrared absorption (GLIIRA), where a pulse of green light causes photochemical and photothermal modifications to the chemical constituents of blood and results in enhanced infrared absorption. We identify a new chemical species, met-hemoglobin, not normally present in healthy human blood but formed during laser photocoagulation which we believe is implicated in the enhanced IR absorption.

Original languageEnglish (US)
Pages (from-to)13-24
Number of pages12
JournalProceedings of SPIE - The International Society for Optical Engineering
Volume4244
DOIs
StatePublished - Jan 1 2001

Keywords

  • Hemoglobin
  • Met-hemoglobin
  • Nd:YAG laser
  • Oxy-hemoglobin
  • Selective photothermolysis
  • Telangiectases

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Condensed Matter Physics
  • Computer Science Applications
  • Applied Mathematics
  • Electrical and Electronic Engineering

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