A Modular, Kerf-Minimizing Approach for Therapeutic Ultrasound Phased Array Construction

Area of Science:

• Ultrasound Technology
• Biomedical Engineering
• Materials Science

Background:

• Histotripsy requires precise control of focused ultrasound.
• Existing phased array fabrication methods face limitations in modularity and aperture utilization.
• Development of advanced transducer designs is crucial for therapeutic ultrasound applications.

Purpose of the Study:

• To develop and test a novel fabrication method for a modular, kerf-minimizing histotripsy phased array.
• To improve aperture utilization and enable individual transducer module replacement.
• To characterize the performance of the fabricated histotripsy array.

Main Methods:

• Utilized a fabrication process involving arbitrarily shaped elements, 3-D printing, water jet cutting, and epoxy coating.
• Fabricated a 750-kHz truncated circular aperture array with modular, arc-shaped elements arranged in concentric rings.
• Characterized the aperture utilization, focal zone dimensions, electrical steering range, and peak negative pressure.

Main Results:

• Achieved 92% aperture utilization with the modular array design.
• Measured a focal zone Full-Width-Half-Maximum (FWHM) of 1.6 mm ×1.1 mm ×4.5 mm.
• Demonstrated successful tissue ablation of a 5 cm³ volume using electric focal steering.

Conclusions:

• The novel fabrication method successfully produced a modular histotripsy phased array with high performance.
• The design allows for maximized aperture utilization and individual module replacement, enhancing transducer longevity and adaptability.
• The array demonstrated effective tissue ablation capabilities, highlighting its potential for therapeutic applications.