[Use of focused ultrasound for local destruction of different brain structures]

It was demonstrated that destruction of the brain can be accomplished by different combinations of ultrasound intensity and duration of irradiation. By experimental means cavitational thresholds of brain tissues were determined and a calculation was made of increased temperature in the zone of focus in each separate regime of irradiation. The authors describe the foci of lesions where the main mechanism of destruction was only warmth, either only cavitation, either warmth and cavitation together. Irradiation of deep brain structures was not accompanied by changes of the cortical and subcortical structures, located above the focus of necrosis along the path of the ultrasound ray (light microscopy). The probability of a target hit into the given brain structure corresponded to the preciseness allowed in a stereotaxic operation.