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Laser beam diameter for port wine stain treatment
Author(s) -
Keijzer Marleen,
Pickering John W.,
van Gemert Martin J. C.
Publication year - 1991
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.1900110616
Subject(s) - port wine stain , dermis , laser , optics , materials science , penetration (warfare) , port wine , absorption (acoustics) , epidermis (zoology) , stain , biomedical engineering , anatomy , pathology , surgery , composite material , medicine , physics , operations research , engineering , staining
Optimal port wine stain treatment requires the selective absorption of light by the ectatic blood vessels. We investigated whether deeper blood vessels can be coagulated, without damaging other cutaneous structures, by varying the laser beam diameter. The penetration of the light was simulated with a random walk (Monte Carlo) program. Scattering of the light plays a major role: practically all light that is absorbed in a blood vessel in the dermis is scattered light. In the epidermis, where the distribution is more centered, a larger beam diameter does not increase the energy density as much as deeper within the dermis where the blood vessels lie and where the light is totally diffuse. Increasing the laser beam diameter from 200 μm to 1 mm or more, makes a typical blood vessel absorb 2.5 times more energy, while the energy absorbed by the epidermis remains the same. The larger the laser beam diameter the better the treatment.