ULTRASOUND PHYSICS > Ch. 14-15 > Flashcards

Ch. 14-15 Flashcards

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1
Q
  1. What is the rationale for the ALARA principle?
    a. carbon footprint​
    b. climate change
    c. patient exposure​
    d. cavitation
A

C

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2
Q
  1. Which of the following is associated with uniform brightness?
    a. amplification​
    b. reject
    c. threshold​
    d. compensation
A

D

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3
Q
  1. 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

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4
Q
  1. 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

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5
Q
  1. Preamplification processes extremely weak signals that are susceptible to noise and often takes place in the transducer.
    a. true
    b. false
A

A

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6
Q
  1. 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

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7
Q
  1. 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

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8
Q
  1. 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

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9
Q
  1. What is the smallest part of a digital picture called?
    a. bit
    b. byte
    c. pixel
    d. fractal
A

C

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10
Q
  1. What is the smallest amount of digital storage called?
    a. bit
    b. byte
    c. pixel
    d. fractal
A

A

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11
Q
  1. 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

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12
Q
  1. 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

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13
Q
  1. The phosphorus of a cathode ray tube converts ____into ____.
    a. electrons, light
    b. light, heat
    c. pressure, electricity
    d. electricity, pressure
A

A

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14
Q
  1. 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

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15
Q
  1. 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

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16
Q
  1. 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

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17
Q
  1. 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

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18
Q
  1. 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

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19
Q
  1. 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

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20
Q
  1. Which of these is a binary number?
    a. 12211221
    b. 10000000
    c. 98635421
    d. 01010102
A

B

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21
Q
  1. 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

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22
Q
  1. 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

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23
Q
  1. What is the number of binary digits required to store 29 levels of gray?
    a. 4
    b. 5
    c. 6
    d. 29
A

B

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24
Q
  1. 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

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25
25. Gray-scale systems typically use ______ as a means of signal dynamic range reduction. a. rejection b. compression c. relaxation d. elimination
B
26
26. The ability of an imaging system to detect weak reflections is called a. compression b. demodulation c. gain d. sensitivity
D
27
27. TGC denotes a. tissue gain characteristic b. time gain compensation c. transducer generator control d. temperature generator control
B
28
28. 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
C
29
29. Gain compensation is necessary due to a. reflector motion b. gray scale c. attenuation d. resolution
C
30
30. 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
D
31
31. 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
C
32
32. 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
B
33
33. Which of the following describes sensitivity? a. Ability of the system to detect weak echoes b. Ability of the system to demonstrate highly reflective interfaces c. Ability of the system to differentiate between two different structures with slightly varying amplitudes d. Ability of the system to distinguish between two closely spaced structures parallel to the beam e. Ability of the system to distinguish between two closely spaced structures perpendicular to the beam
A
34
34. What is rectification? a. The elimination of Positive voltages in the signal b. The conversion of Positive voltages into Negative voltages c. The conversion of Negative signals into neutral signals d. The conversion of Negative voltages into Positive voltages
D
35
35. Which of the following are not operator adjustable? a. compensation and rejection b. amplification and compensation c. demodulation and rectification d. rejection and amplification
C
36
36. The number of frames per second required to prevent flicker is a. between 3 and 6 b. between 6 and 10 c. approximately d. 15 or more
D
37
37. The impedance of the matching layer a. is designed to improve transmission into the body b. must be thick enough to be effective c. is not necessary on the transducers that are focused electronically d. is made with the same material as the damping layer
A
38
38. The dynamic range of the returning echoes a. increases with specular reflectors b. decreases with shadowing artifact c. can be increased with more gel d. is the ratio of the smallest to largest power level the system can process
D
39
39. Gray-scale image display became possible when digital scan converters replaced analog scan converters a. True​​ b. False
B
40
40. the dynamic range is adjusted by the process of a. rejection b. demodulation c. compression d. compensation
C
41
41. The mode in which the strength of the echo is related to the height of deflection on the display is a. B mode b. modified B mode c. A mode d. 3-d imaging
C
42
42. Most of the current scanners use a. analog scan converters b. digital scan converters c. bistable scan converters d. static scan converters
B
43
43. The ability of a scanner to detect weak echoes is called a. compression b. gain c. sensitivity d. threshold
C
44
44. The acoustic power output of the transducer is determined by a. the size of the transducer b. the amplification of the scanner c. the B-mode gain d. the intensity of the voltage sent to the elements
D
45
45. The ultrasound method that uses an optical system to create a visible image of the beam is a. A-mode b. B-mode c. M-mode d. 4 D scanning
B
46
46. The ratio of the largest power to the smallest power the receiver can handle is the a. gain b. threshold c. gain d. dynamic range
D
47
47. TGC refers to a. time gain compensation b. B-mode gain c. amplification of the returning echoes d. increase is power output
A
48
48. For imaging deeper structures, a. the PRF needs to be increased (shorter intervals) b. the PRF needs to be decreased (longer intervals) c. the frame rate needs to be decreased
B
49
49. Write zoom is a ___________ function. a. preprocessing b. postprocessing c. temporal resolution
A
50
50. The frequency of the ______ determines the frequency of the ultrasound pulse (PRF). a. voltage pulse b. bandwidth c. beam former
A
51
51. _________ is the ability of a gray-scale display to distinguish between echoes of slightly different intensities. a. contrast resolution b. spatial resolution c. temporal resolution
A
52
52. The place where the ultrasound beam originates is in the a. signal processor b. beam former c. transmit/receive switch d. pulser
D
53
53. The _________ directs the voltages from the pulser to the transducer during transmission and directs returning echoes to amplifiers during reception. a. Transmit/Receive switch b. channels c. signal processor
A
54
54. The ______ is responsible for electronic beam scanning steering and focusing. a. pulser b. summer c. beam former
C
55
55. The averaging of frames together to provide a smoother appearance is a. spatial compounding b. pixel interpolation c. persistence
C
56
56. The _________ is where the filtering, detection, and compression are done. a. beam former b. Receiver c. Image processor
B
57
57. For proper echo placement on the frame a. a matching layer is on the transducer face b. all echoes from one pulse must be received before the next pulse c. a code is added to the pulser
B
58
58. ________ is the amplification that compensates for attenuation? a. time gain or depth gain compensation (TGCs or DGCs) b. master gains c. the analog to digital converters
A
59
59. A channel is a. a path for transmitting electronic signals b. a method to permit amplification c. the way the images are sent to memory
A
60
60. The number of pixels and the resolution is preserved in a. read zoom b. write zoom c. increased refresh rate
A
61
61. The usual PRF ranges from a. 2 to 25 MHz b. 4 to 20 KHz c. 1 to 10 KHz
C
62
62. The process of pixel interpolation is a. the same as persistence b. part of contrast resolution c. filling in missing pixels
C
63
63. Gain is a ratio of a. the time of the first echo to the last echo b. the amplifier output to input c. the degree of frequency shift
B
64
64. The function of the ADC (analog to digital converter) is a. change electronic voltages to stronger voltages b. compensate for weak echoes c. change analog signals to binary numbers
C
65
65. The function of a bandpass filter is to a. select a range of frequencies b. filter out frequencies above or below the filter c. eliminate unusable frequencies d. all of the above
B
66
66. ___________ is the conversion of radio frequency to video form. a. detection (demodulation) b. amplification c. preprocessing
A
67
67. The ratio of the largest to smallest amplitude or power that a system can process is a. dynamic range b. bandwidth c. gain
A
68
68. The purpose of the pulser is to a. produce electronic voltages to active the crystals b. amplify the weak signals c. select the channel for the signals
A
69
69. The purpose of compression is to a. make the echoes smaller b. make the image fit within the frame of the monitor c. reduce the signal differences to a usable range
C
70
70. The cathode ray tube is used in a. a TV style monitor b. a flat screen LCD monitor c. not used in ultrasound monitors
A
71
71. 3D imaging is accomplished by _____ a. scanning from different angles b. frame averaging c. acquiring many parallel two-dimensional images d. imaging beyond the normal limits of the transducer
C
72
72. The __________ converts the scan line data into images for the frame of display. a. image processor b. signal processor c. analog to digital converter
A
73
73. All the following are functions of the receiver except a. Compensation b. Compression c. Rectification d. compounding
D
74
74. Read Magnification is a. Preprocessing b. Post processing c. Both b. None of the above
B
75
75. Voltage pulses from the pulser go to the a. transducer elements b. transducer and receiver c. transducer and TGC control d. display and image memory e. amplifier and receiver
A
76
76. Amplification processes all reflected signals in a similar manner. a. True b. False
A
77
77. Compensation processes all reflected signals in a similar manner. a. True b. False.
B
78
78. Demodulation is a performed by the a. transmitter b. receiver c. amplifier d. pulser
B
79
79. Which is not a receiver function a. D to A conversion b. demodulation c. compression d. none of the above
A
80
80. The operator control that adjusts the range of the display gray scale a. gain b. power c. smoothing d. compression
D
ULTRASOUND PHYSICS
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