The velocity of ultrasound propagation through brain tissue at low ultrasound frequencies

Abstract

The acoustic properties of the brain tissue have been in the focus of much scientific research. These properties determine the possibilities of the application and development of the ultrasound methods, as well as the development of the equipment used by the neurosurgeon during the resection of the brain tissue. The results of the measurements of these acoustic properties done at megahertz frequency range have been published. Although the velocity of ultrasound wave propagation does not directly influence the distribution of the ultrasound field within the cranium, it enables the determination of the specific resistance, which has an important role in the distribution of the ultrasound field within the cranium. Using the published results and the conditions of the measurements that have been done, the velocity of ultrasound propagation for the frequency range at which cavitation ultrasonic surgical aspirators work has been estimated. After that the measurement of the velocity of the propagation has been done at the frequency of 24 kHz. The values of both the estimated and the measured velocities of the ultrasound propagation prove the validity of the assumptions on which the estimation is based on.