Endocavity Histotripsy for Efficient Tissue Ablation-Transducer Design and Characterization

Area of Science:

• Biomedical Engineering
• Acoustic Technology
• Medical Devices

Background:

• Histotripsy offers non-invasive tissue ablation.
• Small form factor transducers are crucial for endocavity applications.
• Optimizing transducer design is key for efficient volume ablation.

Purpose of the Study:

• To design and test a 34-mm aperture endocavity histotripsy transducer for proof of concept.
• To determine optimal materials and driver design for effective piezoelectric matching.
• To enable efficient volume tissue ablation using a lower frequency transducer.

Main Methods:

• Modeled and tested various materials and drivers for piezoelectric matching.
• Fabricated a 1.5 MHz porous PZT transducer with 3-D printed acoustic lenses.
• Characterized the transducer by measuring pressure fields and output as a function of driving voltage.
• Tested performance by ablating bovine liver tissue volumes.

Main Results:

• Achieved axial and lateral full-width-half-maximums of 6.1 mm and 1.1 mm, respectively.
• Generated 34.5-MPa peak negative focal pressure at 1345 V peak-to-peak driving voltage.
• Successfully ablated liver tissue at the full 17 mm working distance.

Conclusions:

• The designed 34-mm aperture transducer is capable of endocavity tissue ablation.
• The lower frequency (1.5 MHz) facilitates efficient volume ablation.
• This proof-of-concept device shows promise for future medical applications.