1.5-Dimensional Circular Array Transducer for In Vivo Endoscopic Ultrasonography

Area of Science:

• Medical imaging
• Biomedical engineering
• Ultrasound technology

Background:

• Traditional 1-D endoscopic ultrasonography (EUS) transducers lack dynamic elevational focusing and sufficient slice thickness.
• Limitations in current EUS technology hinder precise clinical diagnosis and treatment.

Purpose of the Study:

• To design and fabricate a 1.5-dimensional (1.5-D) circular array transducer for EUS.
• To achieve dynamic elevational focusing in vivo using the developed transducer.

Main Methods:

• An 84x5 element 1.5-D circular array transducer was fabricated using PZT-5H 1-3 composite.
• Acoustic field distribution was measured to validate elevational beam focusing.
• Imaging performance was evaluated using phantoms, ex vivo swine pancreas, and in vivo rhesus macaque rectum.

Main Results:

• The transducer demonstrated a central frequency of 6.47 MHz with 50% bandwidth.
• Low insertion loss (23 dB) and crosstalk (<-26 dB) were achieved.
• Dynamic elevational focusing and enhanced slice thickness in EUS were successfully obtained.

Conclusions:

• The 1.5-D circular array transducer effectively achieves dynamic elevational focusing in EUS.
• This advancement promotes the development of improved EUS probes for precise clinical applications.