A novel, flat, electronically-steered phased array transducer for tissue ablation: preliminary results.

Area of Science:

• Medical Physics
• Biomedical Engineering
• Acoustic Therapy

Background:

• Therapeutic ultrasound utilizes phased arrays for focused energy delivery.
• Current systems face limitations in steering range and treatment volume.
• Need for advanced phased array designs with integrated diagnostics.

Purpose of the Study:

• To investigate flat, lambda/2-spaced phased arrays for therapeutic ultrasound.
• To evaluate electronic steerability, focal characteristics, and acoustic power.
• To compare performance of 1024-element and 6144-element arrays in silico and in vitro.

Main Methods:

• In silico modeling of phased arrays with integrated diagnostic transducers.
• Fabrication and in vitro acoustic power measurements of 1024-element prototypes.
• Hydrophone measurements to validate simulation models of pressure fields.

Main Results:

• Prototypes produced over 100 W acoustic power, matching simulation predictions.
• High electronic steerability demonstrated: minimal pressure drop at 40mm off-axis.
• 6144-element arrays showed <20% amplitude decrease at 100mm off-axis with low grating lobes.

Conclusions:

• The designed phased arrays offer significant electronic steerability for large-volume ablations.
• High acoustic power output is sufficient for rapid thermal ablation at physiological depths.
• These arrays eliminate the need for mechanical translation, improving treatment efficiency.