A Miniature High-frequency Rotary Ultrasonic Encoder for Internal Ultrasound Imaging

High-speed mechanical rotation scanning is the main imaging method of current high-frequency internal ultrasound. Due to uneven drag on the catheter driveshaft leading to changes in the rotational speed, Nonuniform rotational deformity (NURD) is critically limited for the quantitative analysis of internal ultrasound use. To date there have been no techniques shown that provide effective and dynamic modulation of NURD. In this work, a micro structured high-frequency rotary ultrasonic encoder with cylinder gratings was developed, which can dynamically fix the NURD and get high quality restored image. Accordingly, a prototyped micro rotary 50-MHZ ultrasonic encoder with a miniature diameter of 3 mm and a selection of resolutions up to 64 pulses per revolution, which should be the smallest and highest frequency rotary ultrasonic encoder ever reported, was demonstrated based on an endoscopic ultrasound system. The miniature high-frequency rotary ultrasonic encoder shows great potential for ultrasonic endoscopy, OCT, and other mechanical scanning imaging.