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What system control determines the amount of amplification that occurs in the receiver?
Gain
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When you adjust the output power control, you affect the following system component:
Pulser
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What system control do you adjust to equalize the differences in echo amplitudes received from similar structures situated at different depths?
Time gain compensation (TGC)
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Electronic noise is reduced in the ultrasound system by this method:
Rejection
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You have chosen to enlarge an ultrasound image with a read magnification. Which of the following is NOT related to read magnification?
Preprocessing
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What term below describes the rate at which the transmitter applies electronic voltage pulses to the transducer?
Pulse repetition frequency
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Pulsing of the transmitted sound wave is necessary for real-time imaging because:
The depth of the interface from which the echo originated can be determine
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What receiver function is responsible for decreasing the difference between the smallest and largest received signal amplitudes?
Compression
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What receiver function listed below is NOT operator-adjustable?
Demodulation
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While performing a sonographic examination, you have performed both preprocessing and postprocessing functions. Which of the following functions is processing?
Gray-scale map assignment
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Which of the following would be most helpful to enhance the contrast difference between tissues having subtle variations in echogenicity?
Changing the gray-scale map assignment
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What part of the sonographic instrument is responsible for apodization, beam steering, focusing, and aperture control?
Beam former
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What control should you adjust to better compensate for the attenuation of sound as it propagates through tissue?
Time gain compensation
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Which control would you adjust to increase the intensity of the transmitted pulse?
Output power
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Which control would you adjust to alter the dynamic range of the displayed echoes?
Compression
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The technique of frame averaging during real-time acquisition is designed to:
Reduce random noise
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You are performing a sonographic examination and select the tissue harmonics operating mode. What advantage will you obtain over conventional imaging?
Improved contrast resolution
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You have decreased the scan line density. What technique will be employed to fill in the empty data between the scan lines?
Interpolation
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While performing an ultrasound examination, you decide to adjust the system settings to improve the image. Which of the following is NOT user-adjustable?
Echo arrival time
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What control should you adjust to optimize the image if you are scanning a structure that produces very bright echoes on the display?
TGC
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To generate a sonographic image, what is the order in which the following system components are activated?
Pulser, beam former, receiver, memory, display
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What is typical frame rate for B-mode real-time imaging?
10-50 Hz
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What control could you adjust to improve the signal-to-noise ratio on the image?
Frame averaging
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The ratio of the largest to the smallest signal that a system can handle is termed:
Dynamic range
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The term duty factor is defined as:
The fraction of time the transducer is actively transmitting sound
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If you increase the pulse repetition frequency and leave all other controls unchanged, what will happen?
Frame rate will increase
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If you increase pulse repetition frequency to a level too great for the depth of field, the result will be:
Range ambiguity
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You have the ability to adjust the following controls during an abdominal ultrasound study. Which control most closely affects patient exposure?
Output power
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What effect will you see in the image if you increase the reject level?
Decreased low-level echoes
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If sound did not attenuate with increasing depth, what system control would you no longer need?
TGC
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