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50 Cards in this Set
- Front
- Back
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Reducing the likelihood of bioeffects from acoustic energy is the mission of the: a) Nyquist limit b) Reynolds Number c) Huygen's principle d) ALARA principle |
d) ALARA principle |
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The number of cycles in a pulse directly relates to the: a) duty factor b) spatial pulse length c) operating frequency d) pulse repetition frequency |
b) spatial pulse length |
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The Doppler shift frequency is proportional to the: a) cosine values b) Doppler angle c) operating frequency d) velocity of the reflector |
d) velocity of the reflector |
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In the Fraunhofer zone, the beam: a) width diverges b) is conical in shape c) intensity is greater d) intensity is inconsistent |
a) width diverges |
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Artifacts consisting of parallel equally spaced lines are characteristic of: a) multipath b) grating lobes c) reverberation d) range ambiguity |
c) reverberation |
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An increase in reflection amplitudes from reflectors behind a weakly attenuating structure is termed: a) comet tail artifact b) acoustic shadowing c) slice thickness artifact d) acoustic enhancement |
d) acoustic enhancement |
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The ratio of the largest power to the smallest power of the ultrasound system can handle describes: a) bandwidth b) compensation c) dynamic range d) contrast resolution |
c) dynamic range |
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Axial resolution directly relates to the: a) spatial pulse length b) temporal resolution c) transducer diameter d) operating frequency |
d) operating frequency |
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When voltage is applied to the piezoelectric crystal, the crystal will: a) vibrate b) increase in size c) decrease in size d) increase or decrease according to the polarity |
d) increase or decrease according to the polarity |
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The resistance of the arterioles account for approximately what percentage of the total system resistance? a) 25% b) 33% c) 50% d) 75% |
c) 50% |
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Rayleigh scattering is mostly likely to occur when encountering the: a) liver b) pleura c) diaphragm d) red blood cells |
d) red blood cells |
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Which color always represents the baseline in color Doppler imaging? a) red b) blue c) white d) black |
c) white |
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Which of the following correctly defines acoustic frequency? a) length of one cycle b) number of pulses in a cycle c) number of cycles in a pulse d) strength of the compression wave |
c) number of cycles in a pulse |
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What component is not present in A mode but is necessary for B mode imaging? a) clock b) display c) amplifier d) scan converter |
d) scan converter |
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Grating lobes are caused by: a) dynamic focusing b) reverberation artifact c) interference phenomenon d) spacing of the array elements |
d) spacing of the array elements
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Clutter can be reduced using which of the following controls? a) wall filter b) smoothing c) dynamic range d) PRF |
a) wall filter |
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Regions of high density in an acoustic wave are termed: a) reflections b) rarefactions c) transmissions d) compressions |
d) compression |
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Decibel is the unit of measurement for: a) intensity b) pressure c) amplitude d) compression |
d) compression |
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Transmission of the sound wave from one medium to the next is determined by the media's: a) density b) stiffness c) impedance d) propagation speed |
c) impedance |
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focusing of the sound beam: a) decreases beam intensity b) improves lateral resolution c) increases specular reflections d) creates a spacious sound beam over a specified area |
b) improves lateral resolution |
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As the transducer diameter increases the: a) near zone length decreases b) thickness of the element decreases c) intensity in the focal zone increases d) divergence in the far field decreases |
d) divergence in the far field decreases |
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Holding a single image of sonographic information for display is termed a: a) pixel b) scan line c) cine loop d) freeze frame |
d) freeze frame |
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The binary number 0010011 converts to which decimal equivalent? a) 10 b) 19 c) 21 d) 35 |
b) 19 |
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The thickness of the matching layer is equal to: a) the wavelength b) twice the wavelength c) one half of the wavelength d) one quarter of the wavelength |
d) one quarter of the wavelength |
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Which of the following is most likely to improve axial resolution? a) increasing the frame rate b) decreasing the beam width c) decreasing the angle of incidence d) increasing the transducer frequency |
d) increasing the transducer frequency |
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What pulse wave transducer displays a trapezoidal image? a) vector b) linear c) convex d) endocavity |
a) vector |
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Heat sterilization of ultrasound transducers is not recommended, because: a) the transducer's stability decreases b) heat will damage the electric cables c) the piezoelectric properties will be lost d) the transducer assembly cannot withstand the temperature |
c) the piezoelectric properties will be lost |
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The formation of a beam from an aperture is explained by: a) Snell's Law b) ALARA principle c) piezoelectric effect d) Huygens principle |
d) Huygen's principle |
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The Fresnel zone is another for the: a) far zone b) dead zone c) near zone d) focal zone |
c) near zone |
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Proximal to, at, and distal to a stenosis, which of the following must remain constant? a) velocity b) pressure c) resistance d) volumetric flow rate |
d) volumetric flow rate |
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The greater the impedance difference between two structures, the greater the: a) refraction b) reflection c) attenuation d) transmission |
b) reflection |
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Which Doppler angle yields the greatest Doppler shift? a) 0 degrees b) 10 degrees c) 45 degrees d) 60 degrees |
a) 0 degrees |
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Increasing the transducer frequency will: a) decrease contrast resolution b) increase the penetration depth c) increase the amount of attenuation d) decrease sensitivity to Doppler shifts |
c) increases the amount of attenuation |
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Image quality is improved by: a) decreasing the output b) decreasing the frame rate c) increasing the beam width d) shortening the pulse length |
d) shortening the pulse length |
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What is the purpose of the damping material in the transducer assembly? a) increase in sensitivity b) reduction in pulse duration c) improvement in sound transmission into the body d) diminishment of reflections at the transducer surface |
b) reduction in pulse duration |
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Which of the following instruments generates the pulse of sound? a) pulser b) transducer c) beam former d) master synchronizer |
a) pulser |
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Firing delays found in array systems are determined by the: a) receiver b) transducer c) beam former d) master synchronizer |
c) beam former |
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The speed at which a wave travels through a medium is determined by the: a) distance from the sound source b) stiffness and density of the medium c) resistance and impedance of the medium d) amplitude and intensity of the sound beam |
b) stiffness & density of the medium |
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Which of the following is a method for overcoming aliasing? a) shift the baseline b) increase the imaging depth c) decrease the Doppler angle d) increase the operating frequency |
a) shift the baseline |
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Brightening of echoes in the focal zone is a result of: a) acoustic speckle b) slice thickness artifact c) horizontal enhancement d) propagation speed error |
c) horizontal enhancement |
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A disadvantage of duplex imaging is a(n): a) decrease in imaging frame rate b) inability to display peak velocities c) inability to demonstrate flow direction d) decrease in maximum penetration depth |
a) decrease in imaging frame rate |
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Which of the following transducers will produce a longer focal length if the crystal diameter remains constant? a) 5 MHz focused transducer b) 10 MHz focused transducer c) 5 MHz unfocused transducer d) 10 MHz unfocused transducer |
d) 10 MHz unfocused transducer |
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The duty factor in pulse ultrasound is proportional to the: a) pulse duration b) penetration depth c) operating frequency d) pulse repetition period |
a) pulse duration |
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Depth gain compensation is necessary to: a) counteract attenuation b) increase axial resolution c) decrease contrast resolution d) store echo amplitudes and locations |
a) counteract attenuation |
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The Reynolds number predicts the onset of: a) aliasing b) turbulent flow c) a Doppler shift d) biological effects |
b) turbulent flow |
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Which of the following types of resolution does the wavelength have the greatest effect on? a) axial b) lateral c) contrast d) temporal |
a) axial |
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The objective of the matching layer in the assembly of an ultrasound transducer is to reduce the: a) pulse duration b) spatial pulse length c) number of cycles in each pulse d) impedance difference between the element & skin |
d) impedance difference between the element & skin |
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What is the minimum number of memory bits necessary to display 128 shades of gray? a) 2 b) 5 c) 7 d) 10 |
c) 7 |
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Which of the following is a function of read zoom? a) frame averaging b) magnification and display of stored data c) acquisition & magnification of new information d) increase in the number of pixels per inch |
b) magnification & display of stored data |
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Averaging the frame rate is operator adjustable using which of the following functions? a) read zoom b) persistence c) dynamic range d) contrast variation |
b) persistence |
