A transmit/receive 256-channel ultrasound phased array driving system design and strategy for transrib thermal therapy

The purpose of this study is to develop a 256-channel ultrasound transmit/receive system in order to perform rib position detection and independent element activation control that can be applied in transrib liver-tumor thermal therapy. The system comprises of PC/MCU/FPGA duplex communication and triggering so that transmit/receive sequence of each channel can be well controlled. Echo signals received from each element and amplified through a channel-multiplexing circuit. When combining high-speed A/D conversion and USB data transmission, echo signals can be real-time feed into PC for real-time process. The received signals obtained from each element were analyzed and the element obstructing by ribs can be identified. Self-made rib-contained gelatin phantoms were used to validate the accuracy of the algorithm and functionality of the system, and the temperature were feedback from the thermocouple to track the temperature elevation. Preliminary experiments demonstrated that the implemented algorithm can successfully predict the element been blocked by ribs via the received backscattered signals, that brings the capability to dynamically activate/deactivate array elements to avoid rib overheating. The proposed multiple-channel transmit/receive phased arrays system provides potential for improving the successful yields when intending to use 2-D ultrasound phased array to treat the liver tumors noninvasively through ribs.