Fig. 2.

General pulse scheme used to study the effect of low-amplitude acoustic bursts on residual cavitation bubble nuclei. A. Representative waveform acquired from a single 2 MHz histotripsy module; the histotripsy pulse amplitude at the focal location can be estimated as the linear sum of the waveforms from all eight histotripsy modules, suggesting a focal peak negative pressure of approximately 40 MPa. B. Partial segment of the 1 ms bubble removal pulse; all bubble removal pulses had a center frequency of 500 kHz, while the amplitude was varied from 0 to 1.7 MPa. C. Interrogation pulse used to expand residual bubble nuclei remaining in the field; all interrogation pulses were generated by the 500 kHz bubble removal module, had duration of 10 cycles, and amplitude of 2.5 MPa. D. Overall timing of experimental pulse scheme. Further details can be found in the text.