Bubble cloud characteristics and ablation efficiency in dual-frequency intrinsic threshold histotripsy
Connor Edsall1, Laura Huynh2, Timothy L Hall3
1Department of Biomedical Engineering and Mechanics, Virginia Polytechnic Institute and State University, 325 Stanger St., Blacksburg, VA, 24061, United States of America.
Physics in Medicine and Biology
|October 5, 2023
Summary
Dual-frequency histotripsy enhances tissue ablation by controlling cavitation bubble clouds. This method improves lesion precision and ablation efficiency compared to single-frequency approaches.
Area of Science:
- Biomedical Engineering
- Acoustic Physics
- Medical Devices
Background:
- Histotripsy is a non-thermal focused ultrasound tissue ablation technique.
- Acoustic cavitation bubble clouds are key to histotripsy's tissue destruction mechanism.
- Ablation efficiency depends on bubble cloud size and density.
Purpose of the Study:
- Investigate dual-frequency pulsing effects on bubble cloud dynamics and ablation efficiency.
- Explore how varying pulse arrival times influence cavitation.
- Assess lesion formation and efficiency in red blood cell phantoms.
Main Methods:
- Utilized a modular 500 kHz:3 MHz histotripsy transducer.
- Employed dual-frequency pulses with a 1:1 pressure ratio.
- Varied the arrival time of the 3 MHz pulse relative to the 500 kHz pulse.
- Used high-speed optical imaging for cavitation analysis.
- Evaluated lesion formation in agarose and red blood cell phantoms.
Main Results:
- Dual-frequency bubble cloud sizes were intermediate to single-frequency results.
- Pulse arrival time modulated bubble cloud size and dynamics, with early arrival yielding uniform expansion/collapse.
- Red blood cell phantom experiments produced precise lesions with smaller areas and higher ablation efficiencies.
- Dual-frequency histotripsy demonstrated improved ablation efficiency over single-frequency methods.
Conclusions:
- Dual-frequency histotripsy effectively modulates bubble cloud dynamics.
- This modulation allows for precise lesion generation.
- Achieved higher ablation efficiencies compared to single-frequency histotripsy.
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