Focused intravascular ultrasonic probe using dimpled transducer elements

Area of Science:

• Materials Science
• Biomedical Engineering
• Acoustic Engineering

Background:

• Intravascular ultrasound (IVUS) requires high-frequency transducers for detailed imaging of blood vessels.
• Developing advanced piezoelectric materials and fabrication techniques is crucial for improving IVUS probe performance.
• Existing probes face limitations in resolution and material durability.

Purpose of the Study:

• To fabricate and evaluate high-frequency focused intravascular ultrasonic probes using a novel dimple technique.
• To compare the performance of probes made from lead-free KNN-KBT-Mn ceramic and traditional PMN-PT single crystal.
• To assess the potential of the dimple technique for creating high-resolution IVUS transducers.

Main Methods:

• Fabrication of focused ultrasonic transducers using the dimple technique with PMN-PT single crystal and lead-free KNN-KBT-Mn ceramic.
• Characterization of transducer performance including center frequency, bandwidth, and insertion loss.
• Evaluation of transducer imaging capabilities using a wire phantom and ex vivo vessel imaging.
• Measurement of axial and lateral resolutions for both types of probes.

Main Results:

• The lead-free KNN-KBT-Mn probe exhibited a center frequency of 40 MHz, 72% bandwidth, and 28.8 dB insertion loss.
• The PMN-PT probe showed a center frequency of 34 MHz, 75% bandwidth, and 22.9 dB insertion loss.
• The lead-free probe achieved superior -6 dB resolutions of 44 μm (axial) and 125 μm (lateral) compared to the PMN-PT probe (58 μm axial, 131 μm lateral).
• Both probes successfully generated ultrasonic images of good resolution for phantoms and vessels.

Conclusions:

• The mechanical dimpling technique is effective for fabricating high-frequency focused transducers.
• Lead-free KNN-KBT-Mn ceramic probes demonstrate promising performance for intravascular ultrasound applications, particularly in achieving high axial resolution.
• The developed probes show significant potential for enhanced diagnostic imaging in intravascular procedures.