Operational verification of a 40-MHz annular array transducer

Area of Science:

• Ultrasound imaging
• Medical imaging technology
• Materials science (PVDF)

Background:

• Annular arrays offer advanced imaging capabilities.
• Polyvinylidene fluoride (PVDF) is a piezoelectric material suitable for ultrasound transducers.
• Enhancing the depth of field (DOF) is crucial for detailed ultrasound imaging.

Purpose of the Study:

• To present an experimental system utilizing a PVDF annular array for improved ultrasound imaging.
• To evaluate the efficacy of synthetic focusing for enhancing the DOF.
• To characterize the system's performance using phantoms and biological samples.

Main Methods:

• Utilized a 5-ring PVDF annular array with a 6-mm aperture.
• Employed a single-element pulsing and simultaneous digitization of all channels.
• Applied synthetic focusing post-processing to digitized transmit/receive data.
• Validated performance with a wire phantom and imaged an excised bovine eye.

Main Results:

• Synthetic focusing enhanced two-way echo amplitude between 8 and 19 mm.
• Achieved a 6-dB depth of field (DOF) spanning 9 to 15 mm.
• Experimental time delays correlated with theoretical predictions within +/- 2 ns.
• Successfully rendered B-mode images of a bovine eye.

Conclusions:

• The developed experimental system effectively enhances ultrasound imaging DOF using PVDF annular arrays and synthetic focusing.
• Synthetic focusing significantly improves echo amplitude and image quality over a defined range.
• The system demonstrates potential for advanced ultrasound applications requiring extended DOF.