Optical absorption of blood depends on temperature during a 0.5 ms laser pulse at 586 nm

Research output: Contribution to journalArticle

Abstract

Optical properties are important parameters in port wine stain laser treatment models. In this study we investigated whether changes in blood optical properties occur during a 0.5 ms laser pulse, Blood from three volunteers was irradiated in vitro with laser pulses (radiant exposure 2-12 J cm(-2), wavelength 586 nm, pulse length 0.5 ms). Reflection and transmission coefficients, measured using double integrating spheres, decreased slightly during the first part of the pulse. At 2.9 J cm(-2) radiant exposure, the reflectance increased, independent of total radiant exposure of the pulse, This was-caused by blood coagulation, A second sudden increase in reflection and a significant increase in transmission occurred near 6.3 9 cm(-2) and was accompanied by a "popping" sound, indicating rapid expansion of bubbles due to blood vaporization. A multilayered model of blood was used to fit calculated transmission coefficient curves to the measurements and determine temperature-dependent optical blood absorption, Heat diffusion was shown to be of minor importance, A 2.5-fold increase in absorption for temperatures increasing from 20 to 100 degrees C, accurately describes transmission coefficients measured up to 2.9 J cm(-2).

Details

Authors
  • W Verkruysse
  • A. M. K Nilsson
  • T. E Milner
  • J. F Beek
  • G. W Lucassen
  • M. J. C van Gemert
Research areas and keywords

Subject classification (UKÄ) – MANDATORY

  • Atom and Molecular Physics and Optics
Original languageEnglish
Pages (from-to)276-281
JournalPhotochemistry and Photobiology
Volume67
Issue number3
Publication statusPublished - 1998
Publication categoryResearch
Peer-reviewedYes
Externally publishedYes