Tissue changes following application of lasers to the rabbit brain

Abstract

The effect of CO2 and Nd-YAG lasers on rabbit brain tissue was investigated using various energy levels. With a defocussed CO2 laser beam the depth of damage increases with application time; the superficial extension remains nearly equal. In focussed setting the CO2 laser produced deep, fissured incisions; surrounding reactions remain relatively low. With the Nd-YAG laser the depth of the lesion is clearly dependent on the energy applied. In contrast to the absorption of the defocussed CO2 laser beam at the surface, the Nd-YAG laser beam penetrates rather deeply into the brain tissue and produces necroses at even greater depths. The depth effects of laser radiation are limited. The focussed CO2 laser beam appears suitable for cutting and vaporizing brain tissue. With the defocussed Nd-YAG laser beam selected areas may be destroyed by heat with sufficiently accurate prediction of depth.