Transtemporal Ultrasound Holograms for Thalamic Therapy

In this work, we numerically investigate the performance of acoustic holograms at 650 kHz to correct the aberrations introduced by the skull and simultaneously target the thalamic nuclei through the temporal bone window. The influence of a misalignment in the skull-lens relative location is also studied in terms of focus pressure and treated volume. For five different holograms we have seen an improvement on the sonicated target volume compared to the sonicated healthy brain tissue, from 1.5 to 9.5 times better than with a focused transducer. For alignment errors in the skull-lens relative position lower than 3.75 degrees of rotation the hologram produces a field with a peak pressure higher that −1 dB the maximum pressure in the correct position. We demonstrate that transtemporal acoustic holograms are a robust method to improve focus quality and to enhance sonicated volumes on target deep-brain even under small misallocations of the therapeutic ultrasound device that can be used for highly selective and low-cost blood-brain barrier opening and neuromodulation applications.