We have done a study addressing the effects of blood of irradiation with different vascular- lesion lasers. Irradiation of dilute whole blood with light (577 - 585 nm) produced by an argon-dye laser, copper-vapor laser, flashlamp-pumped dye laser or Q-switched frequency- doubled Nd:YAG dye laser causes the release of hemoglobin from the red blood cells. The magnitude of this release is shown to be proportional to the magnitude of thermal insult. With this experimental technique, we compare the efficacy of each laser for producing thermal damage, using clinically realistic irradiation parameters. We have determined that an equivalent energy fluence from these lasers produced comparable amounts of thermal damage in whole blood, except in the experiments where the flashlamp-pumped dye laser was used. The flashlamp-pumped dye laser produced much greater damage than the other lasers at equivalent irradiance levels. This was felt to be due to the flashlamp-pumped dye laser's relatively large spot size. Measurable differences in thermal damage elicited by irradiation of red blood cells with the argon-dye laser and copper-vapor laser emphasized the fact that the latter is a pulsed laser, while former is a continuous-wave laser. All of the experimental results show that laser induced thermal damage is a function of not only the energy fluence, but also of the energy fluence rate and geometry of the irradiation.

Date Published: 7 July 1993
PDF: 7 pages
Proc. SPIE 1882, Laser-Tissue Interaction IV, (7 July 1993); doi: 10.1117/12.147664

Published in SPIE Proceedings Vol. 1882:
Laser-Tissue Interaction IV
Steven L. Jacques; Abraham Katzir, Editor(s)