• Journal of radiological science and technology
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• v.38 no.1
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• pp.7-15
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• 2015

A ultrasonic probe is very important in medical ultrasonic image, but the frequency of probe defects are often. Therefore practical tools for probe based ultrasonic QA should be developed. Advanced research on the effects of the probe defects on the quality of ultrasonic images is required. This study has investigated the effects of the defects in the probe elements influence Doppler images in the medical ultrasonic scanners. Especially the defects in a set of adjacent elements(SAE) electrically disconnected influence Doppler images were tested. The results show Doppler brightness and velocity became rapidly reduced as the defected elements is located centrally, as the defected elements is activated. The more the defected elements increased, the more Doppler brightness and velocity increased. As a set of the element disconnected moved, it appeared Doppler velocity starting to decrease and then was followed by brightness. The strength is not consistent with the velocity in the number and location of the defected elements. The defects in the probe elements influence Doppler velocity when the defected elements got out of the elements activated at Doppler mode.

• Journal of radiological science and technology
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• v.38 no.4
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• pp.443-449
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• 2015

An ultrasound probe has a big impact on Doppler images even though it has very high risk of frequent function-breakdowns occurring in medical ultrasound scanners. This study experimentally analyses the impacts of an ultrasonic probe's defected elements on power & color Doppler images. The results show that, the bigger the size of defected probe elements is, and the closer a group of action elements is to the center, the more the brightness of images and the velocity of Doppler diminish. When elements' defects increase in color & power Doppler images, false images are formed to be mistaken for blood-vessel plaque in neighboring regions. Accordingly, whenever element defects are suspected, we need check-up process in B-mode. From this respective, it is advisable to have primary interest in a probe and carry out continuous probe QA for ultrasonography.

• Journal of radiological science and technology
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• v.37 no.2
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• pp.117-124
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• 2014

This study has investigated the effects of the defects in the probe elements influence Doppler images in the medical ultrasonic scanners. This work was implemented that the quality of Doppler images depended on the extent and location of the probe element defected. The probe performance was rated in terms of the number of piezoelectric elements lost and this was studied in the experiment by electrical disconnection to the elements. The results showed that Doppler velocity became rapidly reduced as the defected elements encountered with the element group activated at the Doppler mode, not as the flow velocity. The effect of the probe defect is decreased when the defects occurred at the element group activated for Doppler mode, as was increased the number of the elements. It was observed that the higher the flow velocity of Doppler flow phantom is, the wider the spectrum of Doppler is. And the Doppler velocity soared up and the dispersion of image brightness is increased when the defected elements got out of the elements activated at Doppler mode. The result showed that TADVP(time-average-Doppler-velocity-profile) is decreased with the increase of the probe element defect, especilly in the region of high frequency. It is expected that the research of various defects of probe elements are needed, and this study can be practical tools for probe based ultrasonic QA in the future.

• The Journal of the Acoustical Society of Korea
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• v.29 no.8
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• pp.476-482
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• 2010

The ultrasonic transient fields and B-mode images of a point target which were simulated for a medical ultrasonic probe with a few defective piezo-elements were compared with those for a normal probe. The present study considered a 3.5 MHz linear array probe whose acoustic beam was formed by the 64 active elements of total 192 elements. The results showed that the maximum amplitude and -3 dB width of the acoustic fields by main-lobes decreased linearly as the defective element number increased from one to four. However, the depths of foci remained almost unchanged, and the pressure differences between main-lobes and side-lobes tended to decrease due to rise in pressures in side-lobes. Such changes in ultrasonic fields affected the B-mode images of point targets. So the artifacts were formed in the right and left side of the target, and the lateral spatial resolutions were decreased while the axial resolution was almost the same.