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XeCl laser ablation of atherosclerotic aorta: Optical properties and energy pathways
Author(s) -
Oraevsky Alexander A.,
Jacques Steven L.,
Pettit George H.,
Saidi Iyad S.,
Tittel Frank K.,
Henry Philip D.
Publication year - 1992
Publication title -
lasers in surgery and medicine
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.888
H-Index - 112
eISSN - 1096-9101
pISSN - 0196-8092
DOI - 10.1002/lsm.1900120604
Subject(s) - irradiation , aorta , laser , specular reflection , ablation , fluence , radiant energy , materials science , optics , radiation , chemistry , medicine , physics , engineering , nuclear physics , cardiology , aerospace engineering
The energetics of 308‐nm excimer laser irradiation of human aorta were studied. The heat generation that occurred during laser irradiation of atherosclerotic aorta equaled the absorbed laser energy minus the fraction of energy for escaping fluorescence (0.8–1.6%) and photochemical decomposition (2%). The absorbed laser energy is equal to the total delivered light energy minus the energy lost as specular reflectance (2.4%, air/tissue) and diffuse reflectance (11.5–15.5%). Overall, about 79–83.5% of the delivered light energy was converted to heat. We conclude that the mechanism of XeCl laser ablation of soft tissue involves thermal overheating of the irradiated volume with subsequent explosive vaporization. The optical properties of normal wall of human aorta and fibrous plaque, both native and denatured were determined. The light scattering was significant and sufficient to cause a subsurface fluence (J/cm 2 ) in native aorta that equaled 1.8 times the broad‐beam radiant exposure, Φ o (2.7Φ o for denatured aorta). An optical fiber must have a diameter of at least 800 μm to achieve a maximum light penetration (≈200 mu;m for μ o /e) in the aorta along the central axis of the beam. © 1992 Wiley‐Liss, Inc.