Sistema de transmissão e recepção de sinais de ultrassom em transdutor matricial 2D

Abstract

The ultrasound scan for medical diagnosis has shown satisfactory results since the late 1950s. The ultrasound has high relevance in the healthcare, because it is a noninvasive medical diagnostic technique and non-ionizing radiation, in addition to the lowcost for providing real-time images, compared to other techniques. For this situation, it is important to understand how the signals that forms the image are captured. Therefore, the purpose of the research was to develop a system that captures ultrasound signals from phantoms that simulate the calcaneal area, through twodimensional matrix transducers, to allow digital signal processing and then characterize materials, with broadband ultrasound attenuation (BUA), specific attenuation and wave propagation speed parameters. The system consists of a Cyclone III EP3C120 FPGA, two Blatek AT23145 transducers, a transmission and reception circuit board, an AFE5805EVM, an ADSDeSer-50EVM, an Olympus 5077PR pulser and two power supplies. The data acquired by the reception unit of the system were received by FPGA, processed and extracted by Signal Tap II and posteriorly analyzed in a digital signal processing software by Matlab. The method used was the transmission-reception, where two transducers with 132 elements and 500 kHz of central frequency were used. The tests were performed at the UTFPR laboratory, with the transducers immersed in a plastic container with water. Two phantoms were used: M6301 QUS 338-2 (normal heel, speed 1560 m/s and BUA 75 dB/MHz) and M6302 QUS 337-1 (osteoporotic heel, speed 1520 m/s and BUA 50 dB/MHz) of the CIRS Inc. The results obtained with the proposed system presented speed of 1554.28 ± 1.94 m/s, with a percentage error of 0.37%, and BUA of 50.85 ± 13.29 dB/MHz for the QUS 338-2 model and speed of 1545.63 ± 1.91 m/s, with a percentage error of 1.69%, and BUA of 60.85 ± 4.56 dB/MHz for the QUS 337-1 model, indicating that the system properly captured the received signals and this technique can be used in the characterization of materials.