Abstract
Abstract High-frequency ultrasound provides better imaging resolutions and noninvasive imaging tool for small animal studies. However, most commercial ultrasound imaging systems are designed for specific applications with fixed modules and the utility imaging functions are thus limited. In this study a high-frequency ultrasound imaging system with real-time imaging process was established for the applications in small animal studies. In system design, one high-frequency ultrasound transducer was mounted on mechanical system. The scanning modes in the system include motion, brightness and swept-scan modes. The user interface provides the connections of control process for automatic operation and data processing function for real-time image display. The design of system synchronous clock eliminated the jitter problem in data acquisition. In addition, the Schottky diode circuits were used to reduce system interference between components. The parallel process in control design of hardware operations and software process improved the performance of the imaging system. In system performance test, 3-cycles, 40-MHz pulse wave, with an acoustic pressure of 500 kPa, were used to scan the heart of zebrafish and human finger’s vein. The frame rate was up to 30 FPS (2 mm × 3 mm) in B-mode status. In zebrafish image, we can estimate the heart rate of 157 beats/min from our motion mode image with a PRF 4 kHz. The finger’s vein experiment by using swept-scan mode with 1 kHz PRF can estimate the blood velocity ranging from 1 to 10 mm/s. In addition, the development of brightness-depth scan mode and back-end analysis system might be able provide larger DOF and precise image in the future. Key words: High-frequency ultrasound, Imaging system, Real-time image