Lead-Free Ultrasonic Phased Array Transducer for Human Heart Imaging

Area of Science:

• Materials Science
• Biomedical Engineering
• Acoustics

Background:

• Lead-free piezoelectric materials face challenges in medical ultrasound due to fabrication difficulties and impedance mismatch.
• Existing lead-based transducers, while effective, raise environmental and health concerns.

Purpose of the Study:

• To develop a high-performance, lead-free ultrasonic array transducer for medical imaging applications.
• To overcome limitations of lead-free materials for transducers operating below 3 MHz.

Main Methods:

• Utilized texture engineering and a stacking piezoelectric-layer design for lead-free (Ba_0.95Ca_0.05)(Ti_0.94Zr_0.06)O₃ ceramics.
• Fabricated an 80-element phased array transducer with a center frequency of 2.9 MHz and >80% bandwidth.
• Evaluated performance using phantom imaging and clinical human heart imaging.

Main Results:

• Achieved a large, uniform lead-free ceramic plate (23×22×0.8 mm³) with a high piezoelectric constant (d₃₃ = 570 pC/N).
• The fabricated transducer demonstrated comparable imaging quality to commercial lead-based transducers.
• Successfully imaged human heart structures with the lead-free phased array.

Conclusions:

• The developed texture engineering and layer-stacking techniques effectively address key challenges in lead-free piezoelectric transducer fabrication.
• This work demonstrates the feasibility of replacing lead-based piezoelectric materials with lead-free alternatives in medical ultrasound phased array transducers.
• The lead-free transducer shows significant potential for safer and environmentally friendly medical imaging solutions.