Laser Fluence for Permanent Damage of Cutaneous Blood Vessels

• Published in: Photochemistry and photobiology Vol. 70; no. 6; pp. 916 - 920
• Main Authors: Barton, Jennifer Kehlet, Vargas, Gracie, Pfefer, T. Joshua, Welch, Ashley J.
• Format: Journal Article
• Language: English
• Published: Oxford, UK Blackwell Publishing Ltd 01.12.1999
• Subjects: Animals; Arterioles - injuries; Arterioles - radiation effects; Cricetinae; Dose-Response Relationship, Radiation; Lasers - adverse effects; Monte Carlo Method; Skin - blood supply; Venules - injuries; Venules - radiation effects
• ISSN: 0031-8655; 1751-1097
• DOI: 10.1111/j.1751-1097.1999.tb08302.x

Treatment of vascular disorders may be improved by a more thorough understanding of laser‐blood vessel interaction. In this study, the probability of permanent damage to a given type and size of blood vessel was determined as a function of fluence at the top (superficial edge) of the vessel lumen. A 532 nm wavelength, 10 ms pulse duration, 3 mm spot size laser was used to perform approximately 250 irradiations of subdermal blood vessels in the hamster dorsal skin flap preparation. The radiant exposure required for a 50% probability of permanent damage was calculated using a probit analysis of experimental results. Threshold radiant exposure increased with larger blood vessel diameters and was greater for arterioles than venules. Monte Carlo modeling of a typical blood vessel geometry revealed that fluence at the top of the blood vessel lumen was amplified by a factor of approximately 2.4 over tissue surface radiant exposure, due to light scattering in the tissue and internal reflection at the skin‐air interfaces.