In Vivo Aberration Correction for Transcutaneous HIFU Therapy Using a Multielement Array

Area of Science:

• Medical physics
• Ultrasound technology
• Biomedical engineering

Background:

• Transcutaneous high-intensity focused ultrasound (HIFU) therapies, particularly boiling histotripsy (BH), face challenges due to body wall heterogeneities causing aberration and loss of focus.
• Accurate focusing is crucial for the efficacy and safety of HIFU treatments.

Purpose of the Study:

• To propose and validate a methodology for in vivo aberration correction for transcutaneous HIFU therapies.
• To demonstrate the effectiveness of aberration correction in restoring focal accuracy and reducing required acoustic power.

Main Methods:

• A custom boiling histotripsy (BH) system with a 256-element phased array was used in pulse/echo mode on a porcine model.
• Aberration correction was achieved by estimating time shifts to maximize the coherence factor of backscattered signals.
• Target tracking was implemented to ensure consistent targeting during iterative correction processes.

Main Results:

• The aberration correction methodology was successfully implemented in vivo on liver and kidney tissues.
• Acoustic power required to induce boiling was reduced by up to 45% with aberration correction.
• The results confirmed the restoration of nonlinear shock front formation at the focus.

Conclusions:

• The developed in vivo aberration correction method is effective for transcutaneous HIFU therapies like BH.
• This technique significantly improves focusing accuracy and reduces energy requirements, enhancing therapeutic potential.
• Aberration correction is a critical advancement for the clinical application of HIFU technologies.