The effect of dual-frequency sonication parameters on the oscillatory behavior of microbubble in blood fluid

This study examines the effect of acoustic driving parameters, both in single and dual-frequency sonication, on the pressure applied to blood vessel walls due to microbubble oscillations in blood. This study aims to derive a safe sonication protocol to open the blood–brain barrier. The finite element method was used to perform simulations of a microbubble. Activations were carried out at 1 MHz (1–3 W/cm2) and 150 kHz (0.1 and 0.2 W/cm2), with 0, π/2, π, and 3π/2 phase differences and different pulse modes. The safe protocols were acquired based on the experimental study. The pulse pressure average created on the vessel wall (PPA) for single-frequency (2.99 kPa, 1 MHz and 116 Pa, 150 kHz) was lower than dual-frequency (4.20 kPa). With increased intensity, PPA increased by 74%–80% for different pulse modes. The effect of duty factor on PPA at 1 MHz and 150 kHz was about 50% and less than 10%, respectively. The maximum change of PPA in phase difference was less than 10%. The order of influence of the studied parameters on the PPA is intensity > duty factor > phase difference. Safe protocols for animal models were reported to open the blood–brain barrier.