Optical absorption of blood depends on temperature during a 0.5 ms laser pulse at 586 nm
Research output: Contribution to journal › Article
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).
|Research areas and keywords||
Subject classification (UKÄ) – MANDATORY
|Journal||Photochemistry and Photobiology|
|Publication status||Published - 1998|