Ch. 14-15 Flashcards
1
Q
- What is the rationale for the ALARA principle?
a. carbon footprint
b. climate change
c. patient exposure
d. cavitation
A
C
2
Q
- Which of the following is associated with uniform brightness?
a. amplification
b. reject
c. threshold
d. compensation
A
D
3
Q
- An entire ultrasound image is too dark, but of uniform brightness. Which of the following is the first adjustment that should be made to make the image brighter?
a. increase TGC
b. increase output power
c. increase compression
d. decrease receiver gain
A
B
4
Q
- An entire ultrasound image is too bright, but of uniform brightness. Which of the following is the first adjustment that should be made to make the image darker?
a. decrease TGC
b. increase compression
c. decrease output power
d. decrease receiver gain
A
C
5
Q
- Preamplification processes extremely weak signals that are susceptible to noise and often takes place in the transducer.
a. true
b. false
A
A
6
Q
- All of the following are true of demodulation EXCEPT:
a. the form of the electrical signal is altered
b. it is comprised of two steps: smoothing and enveloping
c. it is performed automatically by the ultrasound system
d. negative voltages are eliminated
A
B
7
Q
- Which of the following would have the shallowest delay on a TGC curve?
a. 5 MHz linear phased array transducer
b. 3 MHz mechanical scanner
c. 4 MHz continuous wave transducer
d. 2 MHz annular phased array transducer
A
A
8
Q
- Which of the following would have the deepest delay on a TGC curve?
a. 5 MHz linear phased array transducer
b. 3 MHz mechanical scanner
c. 4 MHz continuous wave transducer
d. 2 MHz annular phased array transducer
A
D
9
Q
- What is the smallest part of a digital picture called?
a. bit
b. byte
c. pixel
d. fractal
A
C
10
Q
- What is the smallest amount of digital storage called?
a. bit
b. byte
c. pixel
d. fractal
A
A
11
Q
- A video display that is limited to only black and white, with no other shades of gray, is called ____.
a. binary
b. bistable
c. monochrome
A
B
12
Q
- The information that is processed by a standard duplex US system includes all of the following except:
a. attenuation
b. amplitude
c. frequency
d. time of arrival
A
A
13
Q
- The phosphorus of a cathode ray tube converts ____into ____.
a. electrons, light
b. light, heat
c. pressure, electricity
d. electricity, pressure
A
A
14
Q
- In a standard cathode ray tube used to display ultrasound images, what are the charged particles that are emitted form a “gun” from the rear of tube?
a. electrons
b. positrons
c. photons
d. neutrons
A
A
15
Q
- What is the coating on the inner surface of a cathode ray tube that glows when it is struck by charged particles?
a. sulfur
b. phosphorus
c. tungsten
d. carbon
A
B
16
Q
- How many horizontal scan lines make up an image on a television monitor used in the US?
a. 2500
b. 500
c. 525
d. 1000
A
C
17
Q
- What is the approximate number of frames that must be presented each second for the human eye to perceive the display without flickering?
a. 2
b. 30
c. 100
A
B
18
Q
- What is the maximum number of shades of gray that are represented with 4 bits?
a. 4
b. 8
c. 12
d. 16
A
D
19
Q
- How many bits are required to display 10 different shades of gray? 14 shades? 15 shades?
a. 4 bits, 5 bits, 6 bits
b. 10 bits, 14 bits, 15 bits
c. 4 bits, 4 bits, 4 bits
A
C
20
Q
- Which of these is a binary number?
a. 12211221
b. 10000000
c. 98635421
d. 01010102
A
B
21
Q
- What happens to an image when the # bits allocated to each pixel increases?
a. spatial detail improves
b. frame rate increases
c. field of view expands
d. more shades of gray
A
D
22
Q
- What happens to a digital image when the pixel density increases?
a. spatial detail improves
b. temporal resolution increases
c. the field of view expands
A
A
23
Q
- What is the number of binary digits required to store 29 levels of gray?
a. 4
b. 5
c. 6
d. 29
A
B
24
Q
- The level below which signals are not transmitted through an ultrasound receiver system is the
a. intensity level
b. Threshold, negative, or reject level
c. impedance level
d. dynamic range level
A
B
25
Q
- Gray-scale systems typically use ______ as a means of signal dynamic range reduction.
a. rejection
b. compression
c. relaxation
d. elimination
A
B
26
Q
- The ability of an imaging system to detect weak reflections is called
a. compression
b. demodulation
c. gain
d. sensitivity
A
D
27
Q
- TGC denotes
a. tissue gain characteristic
b. time gain compensation
c. transducer generator control
d. temperature generator control
A
B
28
Q
- Which of the following is the correct list of functions performed by the receiver system in the ultrasound machine?
a. inspection, detection, correction, rejection, depression
b. randomization, amplification, modulation, rectification, limitation
c. amplification, compensation, compression, demodulation and rejection
d. expansion, contraction, band limitation, sonification
A
C
29
Q
- Gain compensation is necessary due to
a. reflector motion
b. gray scale
c. attenuation
d. resolution
A
C
30
Q
- Which of the Following choices is best when the image on your ultrasound system displays reflectors only in a region far from the transducer but no reflectors in a region close to the transducer?
a. Correct gain
b. increase PRF
c. Change transducer
d. Adjust the system’s compensation
A
D
31
Q
- Which of the following choices is best when the image on your ultrasound system is saturated (too bright everywhere)?
a. increase PRF
b. Change transducer
c. Decrease the output power
d. Adjust the system’s compensation
A
C
32
Q
- What system control should you adjust to compensate for sound attenuation with increasing depth?
a. Dynamic range
b. TGC
c. Transmit power
d. Overall receiver gain
e. Focus position
A
B