Bubble Dynamics with the Progress of Histotripsy Yufeng

Bubble Dynamics with the Progress of Histotripsy Yufeng Zhou and Xiaobin Wilson Gao School of Mechanical & Aerospace Engineering Nanyang Technological University

Introduction �Ultrasound therapy is an emerging modality in clinics; �High-intensity low-duration ultrasound pulse can be implemented in drug delivery, thrombolysis, etc. �Histotripsy can be used to erode soft tissue noninvasively; �Bubble dynamics plays an important role in such application.

Experiment Setup

Lesion Growth N=1 N = 20 N=2 N = 50 N=5 N = 70 N = 100 3. 3 MHz, 30 ms burst, 1 Hz pulse repetition rate, 150 W

Passive Cavitation Detection 1 st pulse 100 th pulse 3. 3 MHz, 30 ms burst, 1 Hz pulse repetition rate, 150 W output

Effect of Pulse Duration 3. 3 MHz, 1 Hz pulse repetition rate, 150 W

Lesion Growth N=1 N = 20 N=2 N = 50 N=5 N = 70 N = 100 1. 1 MHz, 100 ms burst, 1 Hz pulse repetition rate, 150 W

Effect of Frequency 1. 1 MHz, 1 Hz pulse repetition rate, 150 W

Ex Vivo Results 3. 3 MHz, 1 Hz pulse repetition rate, 150 W

Ex Vivo PCD 3. 3 MHz, 1 Hz pulse repetition rate, 150 W output

B-Mode Sonography N=1 N = 50 N=5 N = 100 3. 3 MHz, 30 ms burst, 1 Hz pulse repetition rate, 150 W output

Conclusions �Characteristics of bubble dynamics vary with the progress of the ultrasound therapy; �Ultrasound parameters (i. e. , burst duration, frequency, target type) have great influence on the bubble dynamics, thermal effects, and consequent lesion formation; �Appropriate combination of mechanical and thermal effect would broaden the application; �Monitoring bubble dynamics could control the ultrasound therapy effectively and efficiently.