US Physics 271-300
Card Set Information
US Physics 271-300
What system control determines the amount of amplification that occurs in the receiver?
When you adjust the output power control, you affect the following system component:
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)
Electronic noise is reduced in the ultrasound system by this method:
You have chosen to enlarge an ultrasound image with a read magnification. Which of the following is NOT related to read magnification?
What term below describes the rate at which the transmitter applies electronic voltage pulses to the transducer?
Pulse repetition frequency
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
What receiver function is responsible for decreasing the difference between the smallest and largest received signal amplitudes?
What receiver function listed below is NOT operator-adjustable?
While performing a sonographic examination, you have performed both preprocessing and postprocessing functions. Which of the following functions is processing?
Gray-scale map assignment
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
What part of the sonographic instrument is responsible for apodization, beam steering, focusing, and aperture control?
What control should you adjust to better compensate for the attenuation of sound as it propagates through tissue?
Time gain compensation
Which control would you adjust to increase the intensity of the transmitted pulse?
Which control would you adjust to alter the dynamic range of the displayed echoes?
The technique of frame averaging during real-time acquisition is designed to:
Reduce random noise
You are performing a sonographic examination and select the tissue harmonics operating mode. What advantage will you obtain over conventional imaging?
Improved contrast resolution
You have decreased the scan line density. What technique will be employed to fill in the empty data between the scan lines?
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
What control should you adjust to optimize the image if you are scanning a structure that produces very bright echoes on the display?
To generate a sonographic image, what is the order in which the following system components are activated?
Pulser, beam former, receiver, memory, display
What is typical frame rate for B-mode real-time imaging?
What control could you adjust to improve the signal-to-noise ratio on the image?
The ratio of the largest to the smallest signal that a system can handle is termed:
The term duty factor is defined as:
The fraction of time the transducer is actively transmitting sound
If you increase the pulse repetition frequency and leave all other controls unchanged, what will happen?
Frame rate will increase
If you increase pulse repetition frequency to a level too great for the depth of field, the result will be:
You have the ability to adjust the following controls during an abdominal ultrasound study. Which control most closely affects patient exposure?
What effect will you see in the image if you increase the reject level?
Decreased low-level echoes
If sound did not attenuate with increasing depth, what system control would you no longer need?