Histological examination of focused ultrasound effects on human brain tissue
Norman M. Spivak, Alexander S. Korb, Samuel D. Reyes, Brendan P. Bych, Samantha Schafer, Négar Khanlou, Eric Johnson, Mark E. Schafer, Mark S. Cohen, Taylor Kuhn, Alexander Bystritsky
Abstract
Of recent interest in neuromodulation is the use of Low Intensity Focused Ultrasound [1] (FUS), itself a topic of significant interest and of several experiments conducted recently in humans with FUS [2,3]. The FDA Guidance on acoustic output for diagnostic ultrasound limits the derated spatial-peak temporal-average ultrasound intensity (ISPTA.3) to 0.72 W/cm2. Much of the human neuromodulation work has been conducted at this limit [2]. However, as this threshold was established principally for diagnostic, as opposed to therapeutic ultrasound, some groups have conducted research at higher intensities [4], upwards of 6.16 W/cm2 to understand better what range of intensities is most effective for neurostimulation.