Miniaturized High-Resolution Integrated 360° Electronic Radial Ultrasound Endoscope for Digestive Tract Imaging.

Abstract

To improve the accuracy and operating flexibility of digestive diagnostic applications in situ, this paper demonstrates the design, fabrication, and evaluation of a miniaturized high-resolution integrated 360° electronic radial ultrasound endoscope. To improve the uniformity between elements of the radial array transducer, an optimal fabrication procedure based on a flexible matching layer was developed. The radial ultrasound endoscope has a 128.3° 5-million-pixel camera module integrated with an approximately 8-MHz 128-element radial ultrasonic array in a package with an outer diameter of 9.5 mm. The results showed that the array has a center frequency of 8.2 MHz, a -6-dB fractional bandwidth of 83.4%, and a two-way insertion loss of 39.62 dB at the center frequency. Annulus and wire phantoms can be distinctly imaged with the radial array. Printed eight-point font can be distinctly imaged with both a large view and a 3-18-mm depth of field in lumen short-range optical imaging. A porcine esophagus can be distinctly imaged in vitro with the integrated endoscope. The results indicate that the fabrication method based on a flexible matching layer can achieve high uniformity between elements of a radial array transducer. In addition, the proposed ultrasound endoscope demonstrates a good image resolution.