Rectified growth of histotripsy bubbles

Area of Science:

• Acoustic physics
• Biomedical engineering
• Therapeutic ultrasound

Background:

• Histotripsy uses high-amplitude shock waves to fractionate tissue.
• Both cavitation and boiling bubbles are utilized in histotripsy, requiring bubble growth.
• Cavitation bubbles reach ~100 microns, while boiling bubbles grow to ~1 mm.

Purpose of the Study:

• To model and simulate the dynamics of single, spherical histotripsy bubbles.
• To investigate the factors influencing bubble growth during histotripsy.
• To understand the role of heat and mass transport in bubble dynamics.

Main Methods:

• A computational model simulating single spherical bubble dynamics was employed.
• The model incorporated heat and mass transport mechanisms.
• Bubble growth was analyzed under varying conditions, including temperature and waveform shape.

Main Results:

• Asymmetrical waveforms in histotripsy can cause rectified bubble growth.
• Elevated temperatures enhance this bubble growth.
• The rate of bubble growth is sensitive to waveform shape, particularly the pressure-to-shock transition.

Conclusions:

• Waveform asymmetry and temperature are key factors in histotripsy bubble growth.
• Understanding these dynamics is crucial for optimizing histotripsy treatments.
• Further research involves waveform calibration and photographic observation of bubble growth.