Which gain will increase the risk of bioeffects?
a. transmit
b. receive
c. gain
d. overall gain Correct Ans - a. transmit
Which of the following is considered the memory of an ultrasound instrument?
a. pulser
b. transducer
c. receiver
d. beam former
e. digital scan converter
f. display monitor Correct Ans - e. digital scan converter
Spectral broadening suggest:
a. laminar flow
b. turbulent flow
c. flow away from the transducer
d. flow towards the transducer Correct Ans - b. turbulent flow
With pulse wave Doppler axial resolution: Correct Ans - degrades
What color is usually use in color flow Doppler variance map to indicate turbulent flow? Correct Ans -
green
Doppler high pass filter eliminates: Correct Ans - high amplitude signals; low velocity flow
The Doppler wall filter is considered a: Correct Ans - high pass filter
The Nyquist Limit is equal to:
a. propagation speed x frequency
b. propagation speed/ wavelength
c. PRF/2
d. 4xV^2 Correct Ans - c. PRF/2
Multiple echoes, equally spaced originating from a gas bubble is called:
a. comet tail
b. ring down
c. slice thickness artifact
d. multipath Correct Ans - b. ring down
,An increase in red blood cell velocity will_____ the Doppler Shift:
a. increase
b. decrease
c. not change
d. cannot be predicted Correct Ans - a. increase
The primary advantage of CW Doppler is:
a. range resolution
b. range discrimination
c. range ambiguity
d. range gating
e. absence of sampling rate Correct Ans - e. absence of sampling rate
The range for ultrasound begins:
a. 20 Hz
b. 20,000 Hz
c. 2 MHz
d. 15 MHz Correct Ans - b. 20,000 Hz (useful frequency range for clinical imaging is 2MHz-10MHz)
Which instrument control affects the amplitude (dB) of the outgoing signal:
a. gain
b. receiver gain
c. TGC
d. transmit gain
e. overall gain Correct Ans - d. transmit gain; amplitude can be affected by the sonographer
Which of the following is used to convert Doppler shift information into color:
a. high PRF
b. fast Fourier transform
c. autocorrelation
d. time interval histogram Correct Ans - c. autocorrelation
b is incorrect because fast Fourier transform is the method used to process conventional Doppler shift
information but is too slow a method for color Doppler
Pulse repetition frequency Correct Ans - Number of pulses that an ultrasound system transmits into the
body each second. Hz. Typically 4-15 KHz. PRF and depth of a view are inversely related: When system is
imaging deeper, the pulse repetition frequency is lower.
Also the number of pulses created each second
The best way to increase the near field length of an ultrasound beam is to: Correct Ans - increase
transducer diameter
The range of frequencies produced by a damped PZT element is called:
a. fundamental frequencies
b. Q Factor
c. near field
, d. bandwith Correct Ans - d. bandwidth
The percentage of time that the ultrasound instrument is emitting ultrasound is called:
a. PRF
b. pulse duration
c. pulse repetition period
d. duty factor Correct Ans - d. duty factor; the maximum value is 1, the minimum is 0
The unit of duty factor is:
a. Hz
b. mm
c. ms
d. unitless Correct Ans - d. unitless
Quality Factor= Fundamental frequency/ bandwidth Correct Ans - This allows doses of different types of
radiation to be compared for their biological effects.
Increasing wavelength will ___________ frequency.
a. increase
b. decrease
c. not change
d. cannot be predicted. Correct Ans - b. decrease
All of the following directly affect frame rate except:
a. depth of penetration
b. field of view
c. number of focuses
d. line density
e. beam width Correct Ans - e. beam width
A reflection will occur at the boundary of two media if the acoustic impedences of the two media are:
a. equal
b. different
c. unchanged
d. cannot be predicted Correct Ans - b. different
A mechanical transducer utilizes:
a. transmit focus
b. receive focus
c. fixed focus
d. dynamic aperture focusing Correct Ans - c. fixed focus; sonographer cannot determine the location of #
of foci. mechanical transducer uses cross sectional imaging, rotating wheel, wobbler, oscillating mirror
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