A low cost open source high frame-rate high-frequency imaging system

In this paper a low cost open source approach to high-frequency ultrasound imaging is described. This complete imaging system is based around four core components: A single-element geometrically focused imaging transducer, a low cost high frame-rate mechanical scanner, a field programmable gate array (FPGA) controlled pulser-receiver unit, and a data acquisition system running open source interface software. The single-element imaging transducer is spherically curved composite based on Lithium Niobate that has a centre frequency of 45 MHz, a bandwidth of 65%, and an insertion loss of -19dB. The mechanical scanning mechanism is based on a 45 mm long PZT bimorph attached to an extension arm. The mechanism can scan up to a 10 mm displacements at 100 Hz and is driven with a low cost Arduino microcontroller. The mechanism is mounted in an enclosed probe holder filled with deionized water. The FPGA accurately controlling the variable timing of the pulser-receiver unit is a Xilinx Virtex V and the data acquisition hardware consists of an off the shelf AlazarTech PCIe digitizing card and a PC. The hardware communication, GUI/plotting libraries, and data collection is all controlled with an open source Python application we have named OpenHiFUS.