Abstract
Effect of Nd-YAG and CO2 laser beam on micro-vasculature was examined in experimental animal. Soft x-ray microangiography and histological examination of brain after Nd: YAG laser exposure revealed broad avascular or oligovascular zone in the irradiated and the surrounding edematous tissue, in which the survived vessels showed narrowing and tapering without significant leak of blood. These findings seemed to correspond to high hemostatic capability of Nd: YAG laser. Vascular structure in the surrounding edematous layer after CO2 laser exposure, on the other hand, was not so significantly affected by exposure as in Nd: YAG laser, and congested and sometimes ruptured vessels were found close to the central vaporized tissue defect in the coagulation layer, which might cause postexposure hemorrhage.
