Study of rib protection devices based on resistant muffler theory for transcostal focused ultrasound therapy

Abstract

High-intensity focused ultrasound (HIFU) is one of the effective means of treating cancer. One of the current challenges in HIFU treatment is how to minimize thermal damage to the rib during transcostal HIFU treatment and ensure that sufficient energy is delivered to the target area. In this paper, a sound insulation device mounted in front of the rib is proposed to address this challenge. The device is designed based on resistant anechoic theory, combining both reflective and resonant sound energy-blocking mechanisms to enhance the transmission loss and filter bandwidth. The structural parameters of the device are optimized using an orthogonal test method. A finite element method was used to simulate the sound and temperature fields of the sound insulation device with and without different rib spacings. The simulation results demonstrate a significant decrease in sound pressure at the ribs under the protection of the sound insulation device, with no significant difference in sound pressure at the target area. Consequently, the temperature at the ribs decreases, while the temperature at the target area tissue is guaranteed. Furthermore, transcostal HIFU experiments are conducted using real pig ribs and the experimental results validate the accuracy of the simulation results.