Chapter 14 quiz Flashcards
(20 cards)
Is patient exposure levels to ultrasound energy altered when the sonographer changes amplification?
No
TRUE OR FALSE
Smoothing converts all negative voltages into positive voltages
False
Which does not belong as a major component in the ultrasound system?
a. master synchronizer
b. transducer
c. switch
d. pulser and beam former
Switch
TRUE OR FALSE
When signal-to-noise ratio is high, the signal is much stronger than the noise and the image is of high quality
True
In the amplification process, the typical values are measured in dB, the range is
60-100dB
TRUE OR FALSE
Compensation is performed twice
False
This allows the sonographer to control whether the low-level gray scale information within the data will appear on the displayed image
Reject
What does ALARA mean
As low as reasonably achievable
Place these functions in order in which the ultrasound system performs them
a. reject
b. amplification
c. demodulation
d. compensation
e. compression
- b. amplification
- d. compensation
- e. compression
- c. demodulation
- a. reject
Receiver gain is also called
amplification
Can the sonographer change demodulation
no
All electrical signals in the receiver are affected ______________ by amplification
Identically
Preamplification occurs as close to the active elements as is practical, often in the
Transducer
TRUE OR FALSE
The pulser creates electrical signals that excite the PZT crystals and create sound beams. When pulser voltage is high, the transducer’s active element vibrates more forcefully and transmits stronger sound beams into the body
True
Another name for pulser voltage is
Transmitter output
Can output power alone make an image of uniform brightness from top to bottom?
No
Which of the following choices is best when the image on your ultrasound system is too bright everywhere?
a. decrease the amplification or gain
b. use a higher frequency transducer
c. decrease the output power
d. adjust the reject
decrease the output power
Which of the following choices is best when the image on your ultrasound system displays reflections only in a region far from the transducer but no reflectors in a region closer to the transducer?
a. adjust the system’s compensation
b. use a higher frequency transducer
c. decrease the output power
d. adjust the reject level
adjust the system’s compensation
TRUE OR FALSE
Both levels of reject can be adjusted by the sonographer
False
BONUS
Draw the anatomy of the TGC curve
Near gain Delay Slope Knee Far gain