CMOS Ultrasound Transceiver Chip for High-Resolution Ultrasonic Imaging Systems.

The proposed CMOS ultrasound transceiver chip will enable the development of portable high resolution, high-frequency ultrasonic imaging systems. The transceiver chip is designed for close-coupled MEMS transducer arrays which operate with a 3.3-V power supply. In addition, a transmit digital beamforming system architecture is supported in this work. A prototype chip containing 16 receive and transmit channels with preamplifiers, time-gain compensation amplifiers, a multiplexed analog-to-digital converter with 3 kB of on-chip SRAM, and 50-MHz resolution time delayed excitation pulse generators has been fabricated. By utilizing a shared A/D converter architecture, the number of A/D converter and SRAM is cut down to one, unlike typical digital beamforming systems which need 16 A/D converters for 16 receive channels. The chip was fabricated in a 0.35-mum standard CMOS process. The chip size is 10 mm(2), and its average power consumption in receive mode is approximately 270 mW with a 3.3-V power supply. The transceiver chip specifications and designs are described, as well as measured results of each transceiver component and initial pulse-echo experimental results are presented.

Toward imaging the dynamic interaction between actin and myosin using a wet-cell C-mode near-field optical microscope.

This paper describes the implementation of a wet-cell collection-mode near-field optical microscope that has been constructed with the long term goal of imaging the myosin conformational change as it interacts with actin. The bioassay used to prepare the samples involved lysing muscle fibers to exact and myosin molecules which were fixed to a mica slide. Next, actin filaments were exacted and deposited in the region of the myosin. The wet-cell allows the addition of water containing ATP and the necessary ions to activate the myosin biomolecules. The near-field optical microscope was shown to able to resolve features of the size of the actin and myosin biomolecules.

Implementation of a system using reflective tomographic reconstruction for breast cancer detection.

The following describes the implementation of a system for ultrasonic mammography. The system employs adaptive imaging and processing techniques to produce high-resolution breast tissues sonograms. The time-domain imaging technique provides quantitative maps of intrinsic acoustic tissue properties using conventional pulse-echo transducers and clinical scanning system. The increased image resolution and quantitative maps provide improve diagnostics tools compared with conventional B-scan images.