| Summary: | 碩士 === 南台科技大學 === 電機工程系 === 97 === In clinic, the ultrasonic densitometry on calcaneus is always based on PC type I/O card technique. As the pulser voltage was limited up to 300 V, the estimation of bone tissue characteristic only could be estimated by the transmitted pulser, not by the echo pulse.
This work was major in utilizing the power electronics technology to build a high-voltage ultrasonic pulser (300 ~ 500 volts ) with high power factor. Then the high-speed AD converters and the ultrasonic receiver were integrated with FPGA technology. Finally the transmitted or the echo ultrasound signal was designed to transfer to a notebook (NB) with USB port through the designed platform between the FPGA and the LabVIEW. In addition, the speed of sound (SOS) and the broadband ultrasound attenuation (BUA) could be measured by the NB on real time. AS a result, the ultrasonic densitometry can estimate the characteristic of bone tissue based on transmitted signal with the portable system based on proposed FPGA technique.
The system verification can be divided into two parts. The first part is to estimate the precision and validity from investigation examining acrylic plastic and phantoms. The results show the accuracy of SOS in simulating bone phantom is (normal bone phantom: 97.3%, osteoporotic bone phantom: 99.4%). The accuracy of BUA in simulating bone phantom is (normal bone phantom: 97.4%, osteoporotic bone phantom: 88.8%).The second part is in vivo test and comparing with densitometry (UBIS-5000) to calibrate precision of the system. The results show the accuracy of SOS is 98.5%, and the accuracy of BUA is 92.1%.Furthermore, high accuracy of SOS and BUA in bone phantom simulation and in vivo measurement are showed on the results. It concludes that this system is an effective portable ultrasound densitometry.
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