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50 Cards in this Set
- Front
- Back
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The frequency of a sound wave is determined by:
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Its source
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T/F Sound waves are described by frequency
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True
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T/F Sound waves are described by amplitude
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True
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T/F Sound waves are described by perpendicular incidence
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False
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T/F Sound waves are described by band width
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False
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T/F Sound waves are described by propagation speed
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True
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The term for the output of batteries is:
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Direct current
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The term for the output of household current is:
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Alternating current
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Household alternating current has a frequency of:
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60 Hertz
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Propagation speed is dependent upon:
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The medium through which the sound wave passes
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Ultrasound waves described by:
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Pressure
Particle motion Density Temperature |
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As the frequency of an acoustic variable increases, the wavelength:
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Decreases
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As stiffness increases, propagation speed:
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Increases
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The term period is related to frequency by the fact that it:
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Is the reciprocal of frequency
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Spatial pulse length is equal to:
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The wavelength times the number of cycles in the pulse
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Wavelength is measured in:
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mm
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The units of attenuation are:
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Db
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As frequency increases, the attenuation coefficient:
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Increases
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Intensity is equal to:
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Power/area
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With an ultrasound probe frequency of 10 MHz the period will be:
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0.10 microseconds
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Wavelength is equal to the propagation speed:
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Devided by frequency
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Spatial pulse length is equal to the number of cycles in the pulse:
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Times wavelength
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In ultrasound imaging, resolution is described as:
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Axial and lateral
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As frequency increases, axial resolution:
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Improves
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Axial resolution is described using the term:
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Millimeters
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Doppler signal processing describes the:
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Comparison of the reflected frequency with the transmitting frequency
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In Doppler ultrasound evaluation, the blood acts mainly as a:
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Small reflector
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The propagation speed of sound through soft tissue is:
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1540 m/s
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Attenuation of a sound beam through tissue may be related to:
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Reflection of sound waves
Scattering of sound waves Absorption of ultrasound Depth of sound penetration |
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The _______ the MHz, the shallower the penetration depth:
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Higher
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The reflected Doppler signal contains how many frequencies:
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The number is proportional to the blood cell velocities
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The frequency of ultrasound is determined by the number of oscillations per second produced by:
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An oscillator
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Ultrasound is defined as frequency:
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Greater than 20 kHz
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When an ultrasound reflector is moving away from a source, the reflected frequency may be:
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1/2 the incident frequency
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The largest Doppler shift occurs when the beam of ultrasound insonates the vessel at what angle?
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0 degree angle
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Movement toward a transducer produces an upward shift in the reflected frequency. Circuits within a directional Doppler would detect this as:
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Antegrade flow
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Piezoelectric crystals in a Doppler transducer provide:
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Generating & detecting sound waves; converting pressure into electrical signals; converting electrical signals into mechanical vibrations; converting mechanical vibrations into electrical signals
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The one factor in the Doppler equation that is unknown when using Doppler ultrasound by itself is:
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The angle of incidence
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The area where the transmitting and receiving beam profiles cross paths is known as the:
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Zone of sensitivity
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The frequency of a transducer is determined by:
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The number of times the crystal is electronically stimulated & the size and shape of the transducer
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The estimated absorption or attenuation of ultrasound in soft tissue is:
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0.5 db/cm/MHz
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Frequency is defines as:
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The number of complete cycles per unit of time
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Power is defined as:
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Work/time
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Power divided by the beam area is equal to the:
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Intensity
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Units of acoustic power output are:
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W/cm squared
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Focusing a sound beam with its power remaining constant will cause:
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Increases intensity at the focal point
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The strength of a sound beam is best described by:
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Amplitude and intensity
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Reduction in the strength of a sound beam as it travels through a medium is defined as:
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Attenuation
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The absorption, reflection and scattering of a sound beam can be described as:
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Attenuation
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According to the Biological Effects Committee, no confirmed significant bioeffects have been reported at intensities below:
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100 mW/cm squared
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