Non-invasive cavitation nuclei trap for Histotripsy

The high velocities encountered in major vessels impede potential drug-free thombolysis treatments such as Histotripsy by lowering the gas concentration that is known to promote inertial cavitation and soft tissue fragmentation. The ”ultrasonic tap” can retain microbubbles in a highly localised region, against the vessel wall. Phospholipid microbubbles flowing through a 4 mm wall less vessel at a depth of 30 mm within a tissue mimicking phantom were successfully accumulated at a single location. The same ultrasound medical probe was used to emit the acoustic field required to trap the microbubbles, acquire B-Mode frames and induce inertial cavitation for concentrations of 10⁶ and 10⁷ MB/ml. Inertial cavitation was measured through 17 mm of tissue mimicking material with similar frequency dependent attenuation to human tissue.