Abstract

Small-size lesions to cerebral cortex induced by the CO₂ laser have found applications in neurophysiology for anatomical-functional mapping of the brain functions by areas. The advantage of this new technique in comparison to traditional ones (mechanical, electrical and chemical methods) consists in the possibility of making well-controlled lesions of small and repeatable size to cerebral cortex. In this work, we employed numerical and physical modelling to study the effect of the CO₂ laser beam diameter and power density on the ablation rate, size and shape of the laser-induced lesions. Our study showed that the existing linear mathematical model of the laser-induced ablation is sufficiently correct only for the case of relatively shallow lesions. For large penetration depths, the mathematical model of laser-tissue interaction that accounts for the exponential decay of laser power density with penetration depth gave better agreement with the experiment than the existing linear model.

© 2003 SPIE