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28 Cards in this Set
- Front
- Back
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a sonogram is synonymous with an ultrasound examination T/F
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true
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Who is the one who first noted that the angle of incidence is equal to the angle of relfection?
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Leonardo da vinci
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When was the priciple of piezoelectricity discovered?
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1880
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what is the reverse piezoelectric effect?
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generating a mechanical ultraosund beam by appyling a voltage to the piezoelectric material
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who was the one who first descrived A-mode?
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Leksell
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Who made the first published attempt to use ultrasound for imaging of the human body?
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dussik
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When was the first digital ultrasound introduced?
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1982
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What is simple harmonic motion?
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When particles move with the passage of a sound wave so that they move past their points of rest
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what is compression?
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the region where particles are closest together.
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what is the region of minimum displacement of particles?
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at the nodes
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which of the following is not a wave variable?
a)Density b)pressure C)distance d)wavelength |
wavelenth is not a wave variable
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What is density measured in?
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kg/cm3
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explain acoustic variables
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aka wave variables:
do not change while the ultrasound wave passes |
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what is the maximum variation of acoustiv variables?
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amplitude
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HOw does intensity relate to amplitude?
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intesity varies directly with the square of the amplitude
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If an amplitude of 5 produces an intensity of 100, and an amlitude is adjuscted to 9, what is the new intensity?
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324`
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What is a formula for duty factory?
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time on/time on + time off
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As density increases, how does this affect propegation speed?
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propegation speen decreases
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as amplitude increases, how does this affect wavelength?
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wavelength is unchanged
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as period increases, how does this affect resolution?
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resolution degrades
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why are mechanical transducers obsolete?
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because they are incompatable with current computer technology
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T/F Annular array is considered strictly mechanical?
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F-annular arrays are considered both mechanical and electronic
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T/F TGC is an overall sensitivity control
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false
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What is another name for reject?
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suppression
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As frequency increases, how does this affect TGC slope?
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TGC slope becomes steeper
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How does the byte length relate to shades of gray?
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the longer the byte length, the more shades of gray
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Why should the image depth be adjusted properly?
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so the go return time can be minimized
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Why is reject seldom increased during 2D imaging?
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because sonographers want all the shades of gray they can get.
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