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PHYSICS > Chapter 8/9 Kremkau Final > Flashcards

Chapter 8/9 Kremkau Final Flashcards

1
Q

a small transducer element mounted on the end of a narrow tube; a piezoelectric membrane with small metallic electrodes

A

hydrophone

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2
Q

tissue-equivalent device that has characteristics that are representative of tissues

A

phantom

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3
Q

the force exerted by a sound beam on an absorber or reflector

A

radiation force

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4
Q

a device without tissue-like properties that is designed to measure some characteristic of an imaging system

A

test object

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5
Q

Which of the following is not assessed with a tissue equivalent phantom?
a. penetration
b. beam width
c. dynamic range
d. TGC operation

A

b

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6
Q

Tissue equivalent phantoms are filled with a substance containing ______.

A

graphite

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7
Q

Which of the following cannot be measured or calculated by a hydrophone?
a. period
b. amplitude
c. impedance
d. pulse duration

A

c

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8
Q

Which of the following pulsed imaged techniques demonstrates the highest acoustic output?
a. gray-scale
b. motion mode
c. color-doppler
d. spectral doppler

A

d

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9
Q

Test objects evaluate _______.

A

detail resolution

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10
Q

A hydrophone is used in the following form(s):
a. a small transducer element mounted on end of hollow needle
b. a large piezoelectric membrane with small electrodes on both sides
c. both a and b
d. neither

A

c

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11
Q

which of the following pulsed-wave techniques demonstrates the lowest sonographic output?
a. motion mode
b. gray scale
c. color doppler
d. spectral doppler

A

b

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12
Q

Doppler test objects and flow phantoms enable the evaluation of all of the following except:
a. spectral display and calibration
b. color doppler spatial resolution
c. sample volume location
d. penetration of spectral and color Doppler instruments

A

b

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13
Q

True or False:

Hydrophones are used to measure the acoustic output of various sonographic instruments

A

true

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14
Q

True or False:

Doppler test objects and flow phantoms are not able to evaluate gate location.

A

false

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15
Q

In soft tissue, a temperature is considered significant once it exceeds _____.

A

1.5 degrees celcius

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16
Q

which of the following describes cavitation?
a. flow in an absorbing fluid
b. conversion of ultrasound to heat
c. temperature rise as ultrasound propagates through tissue
d. production and behavior of bubbles in a liquid medium

A

d

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17
Q

No bioeffects have been observed in mammation tissues that contained well-defined gas bodies at peak rarefactional pressure values (mPa) of less than ____

A

0.4

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18
Q

Plant studies are used primarily for _____.

A

understanding cavitational effects in living tissue

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19
Q

The extent of temperature rise produced depends on ____ and _____.

A

intensity and frequency

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20
Q

which of the following pulsed imaging techniques demonstrates the highest acoustic output?
a. gray scale
b. motion mod
c. color doppler
d. spectral doppler

A

d

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21
Q

No bioeffects have been observed in mammation tissues at mechanical index values of less than ____.

A

0.4

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22
Q

Attenuation in soft tissue is due primarily to

A

absorption

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23
Q

which of the following relates to heating?
a. impedance
b. sound speed
c. distance from transducer
d. absorption

A

d

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24
Q

a significant increase in the temperature of tissues close to the transducer is a result of _____.

A

transducer self-heating

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25
Q

A tissue-equivalent _____ has an attenuation of approximately 0.5 dB/cm-MHz and a propagation speed of 1.54 mm/us. A ______ does not mimic tissue but provides a means for measuring some aspect of instrument performance.

A

phantom, test object

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26
Q

True or False:

Test objects and phantoms are available commercially

A

true

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27
Q

true or false:

Test objects and phantoms can be used by the instrument operator.

A

true

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28
Q

A moving ____ test object is useful in checking the accuracy of Doppler spectral displays.

A

string

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29
Q

A _____ phantom is useful in simulating physiologic ______ conditions for a Doppler instrument.

A

flow, flow, f

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30
Q

Which of the following is used for Doppler sensitivity measurements?
a. cyst phantom
b. profile test object
c. string test object
d. contrast phantom
e. none of the above

A

e

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31
Q

tissue-equivalent phantoms attempt to represent some acoustic property of _____.

A

tissues

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32
Q

true or false:

The string test object measures volumetric flow rate.

A

false

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33
Q

With use of a hydrophone, which of the following can be measured or calculcated. (There is more than one correct answer)
a. impedance
b. amplitude
c. period
d. pulse duration
e. pulse repetition period

A

bcde

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34
Q

True or false:

All hydrophones consist of a small element mounted on the end of a needle.

A

false

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35
Q

A needle hydrophone contains a small ______ element.

A

transducer and piezoelectric

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36
Q

True or false:

Because of its small size, a hydrophone can measure spatial details of a sound beam.

A

true

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37
Q

A hydrophone _____.
a. interacts with light
b. produces a voltage
c. measures intensity directly
d. measures total energy
e. none of the above

A

b

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38
Q

Heating depends most directly on:

A

SATA intensity

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39
Q

Conditions under which cavitation may occur are best described by ____.

A

peak rarefactional pressure

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40
Q

Bioeffects have been observed in experimental animals with intensities greater than ____.

A

100mW/cm^2 SPTA

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41
Q

Bioeffects have been observed in experimental animals with focused intensities greater than _____.

A

1 mW/cm SPTA

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42
Q

Focal lesions have been observed in experimental animals with intensities greater than _____.

A

10 W/cm SPTA

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43
Q

True or False

The available epidimiologic data are sufficient to make a final judgement on the safety of diagnostic ultrasound.

A

false

44
Q

Exposure is minimized by using diagnostic ultrasound ____.

A

only when indicated, with minimum intensity, with minimum time

45
Q

Which of the following is (are) used currently to indicate output on the display?
a. percent
b. display
c. SPTA intensity
d. mechanical index
e. all of the above

A

e

46
Q

Which of the following affect(s) exposure of a fetus?
a. intensity at the transducer
b. distance to the fetus
c. frequency
d. gain
e. more than one of the above
f. all of the above

A

e (a,b,c)

47
Q

True or false

There is no possible hazard involved in the use of diagnostic ultrasound

A

false

48
Q

True or false

Ultrasound should not be used as a diagnostic tool because of the bioeffects it can produce

A

false

49
Q

No independently confirmed, significant bioeffects in mammalian tissues have been reported at intensities below _____.

A

100 mW/cm^2 SPTA

50
Q

Is there any known risk with the current use of diagnostic ultrasound?

A

no

51
Q

are there any bioeffects that ultrasound produces in small animals under experimental conditions?

A

yes

52
Q

Which of the following are mechanisms by which ultrasound can produce bioeffects?
a. direction ionization
b. absorption
c. photoelectric effect
d. cavitation
e. Compton effect

A

b and d

53
Q

Which of the following relates to heating?
a. impedance
b. sound speed
c. absorption
d. refraction
e. diffraction

A

c

54
Q

Which of the following endpoints is documented well enough in the scientific literature to allow a risk assessment for diagnostic ultrasound to be based on it?
a. fetal weight
b. sister-chromatid exchange
c. fetal abnormalities
d. carcinogenesis
e. none

A

e

55
Q

On which of the following endpoints has more than one epidemiologic study shown a statistically significant effect of ultrasound exposure?
a. fetal activity
b. birth weight
c. fetal abnormalities
d. dyslexia
e. none

A

e

56
Q

Which of the following acoustic parameters has (have) been documented in ultrasound epidemiologic studies published thus far?
a. frequency
b. exposure time
c. intensity and pulsing conditions
d. scanning patterns
e. none

A

e

57
Q

A device commonly used to measure the output of diagnostic ultrasound instruments is a(n) _____.

A

hydrophone

58
Q

A typical output intensity (SPTA) for an ultrasound imaging instrument is ____.

A

1 mW/cm^2

59
Q

Which of the following typically has the highest output intensity?
a. fetal monitor Doppler
b. duplex pulsed Doppler
c. color-Doppler shift
d. phase array, gray scale

A

b

60
Q

As far as we know now, which of the following is the most correct and informative response to a patient’s question, “Will this hurt me or my baby?”
a. no
b. yes
c. We don’t know
d. The risks are well understood, but the benefits always outweigh them
e. there is no known risk with ultrasound imaging as it is applied currently

A

e

61
Q

To minimize whatever risk there may be with ultrasound imaging, which of the following should be done?
a. can to produce pictures for the family album
b. scan to determine fetal sex
c. minimize exposure time
d. scan for medical indication(s) only
e. minimize exposure intensity

A

c d e

62
Q

Which of the following controls affect instrument output intensity?
a. dynamic range, compression
b. transmit, output
c. near gain, far gain
d. overall gain
e. slope, time gain compensation

A

b

63
Q

Which of the following are correct for a duplex, pulsed-wave Doppler instrument?
a. tissue anywhere in the Doppler beam is exposed to ultrasound
b. tissue anywhere in the imaging plane is exposed to ultrasound
c. Imaging intensities are higher than for conventional gray-scale instruments
d. Doppler intensities are higher than for continuous-wave fetal monitoring

A

a b d

64
Q

The tissue of greatest concern regarding bioeffects in an abdominal scan is the ____.

A

fetus

65
Q

Would it be wise to substitute a duplex, pulsed-wave Doppler device for an inoperative fetal monitor for long-term monitoring in labor?

A

no

66
Q

Which of the following is (are) likely to be exposed to ultrasound during a diagnostic study?
a. patient
b. sonographer
c. sonologist
d. observers in the room
e. more than one of the above

A

a

67
Q

No bioeffects have been observed in nonhuman mammalian tissues at thermal index values of less than _____.

A

2

68
Q

No bioeffects have been observed in nonhuman mammalian tissues at mechanical index values of less than ____.

A

0.4

69
Q

No bioeffects have been observed in nonhuman mammalian tissues at peak rarefactional pressure values (megapascals) of less than _____.

A

0.4

70
Q

ALARA is an abbreviation for _____.

A

as low as reasonably achievable

71
Q

A tissue-equivalent ____ has an attenuation of approximately 0.5 dB/cm-MHz and a propagation speed of 1.54 mm/us. A ______ does not mimic tissue but provides a means for measuring some aspect of instrument performance.

A

phantom, test object

72
Q

Test objects and phantoms are available commericially

A

true

73
Q

Test objects and phantoms can be used by the instrument operator.

A

true

74
Q

A moving _____ test object is useful in checking the accuracy of Doppler spectral displays

A

string

75
Q

A _____ phantom is useful in simulating physiologic _____ conditions for a Doppler instrument.

A

flow, flow,

76
Q

Which of the following is used for Doppler sensitivity measurements?
a. cyst phantom
b. profile test object
c. string test object
d. contrast phantom
e. none of the above

A

e

77
Q

Tissue-equivalent phantoms attempt to represent some acoustic property of _____

A

tissues

78
Q

The string test object measures volumetric flow rate.

A

false

79
Q

With use of a hydrophone, which of the following can be measured or calculated?
a. impedance
b. amplitude
c. period
d. pulse duration
e. pulse-repetition period

A

b c d e

80
Q

All hydrophones consist of a small element mounted on the end of a needle

A

false

81
Q

A needle hydrophone contains a small _____ element.

A

transducer/piezoelectric

82
Q

Because of its small size, a hydrophone can measure spatial details of a sound beam.

A

true

83
Q

A hydrophone ______.

A

produces a voltage

84
Q

Heating depends most directly on

A

SATA intensity

85
Q

Conditions under which cavitation may occur are best described by _____

A

peak rarefactional pressure

86
Q

Bioeffects have been observed in experimental animals with intensities greater than ______

A

100 mw/cm2 SPTA

87
Q

Bioeffects have been observed in experimental animals with focused intensities greater than ______

A

1 W/cm SPTA

88
Q

Focal lesions have been observed in experimental animals with intensities greater than ______.

A

10 W/cm SPTA

89
Q

The available epidemiologic data are sufficient to make a final judgment on the safety of diagnostic ultrasound.

A

False

90
Q

Exposure is minimized by using diagnostic ultrasound _____.

A

with minimum intensity, time, and when indicated

91
Q

Which of the following is (are) used currently to indicate output on the display?
a. percent
b. decibel
c. SPTA intensity
d. mechanical index
e. all of the above

A

e

92
Q

Which of the following affect(s) exposure of a fetus?
a. intensity at the transducer
b. distance to the fetus
c. frequency
d. gain
e. more than one of the above
f. all of the above

A

e

93
Q

There is no possible hazard involved in the use of diagnostic ultrasound.

A

false

94
Q

Ultrasound should not be used as a diagnostic tool because of the bioeffects it can produce

A

flase

95
Q

No independently confirmed, significant bioeffects in mammalian tissues have been reported at intensities below _____.

A

100 mW/cm2 SPTA

96
Q

Is there any known risk with the current use of diagnostic ultrasound?

A

no

97
Q

Are there any bioeffects that ultrasound produces in small animals under experimental conditions?

A

yes

98
Q

Which of the following are mechanisms by which ultrasound can produce bioeffects?
a. direct ionization
b. absorption
c. photoelectric effect
d. cavitation
e. Compton effect

A

b d

99
Q

Which of the following relates to heating?
a. impedance
b. sound speed
c. absorption
d. refraction
e. diffraction

A

c

100
Q

Which of the following endpoints is documented well enough in the scientific literature to allow a risk assessment for diagnostic ultrasound to be based on it?
a. fetal weight
b. sister-chromatid exchange
c. fetal abnormalities
d. carcinogenesis
e. none

A

e

101
Q

On which of the following endpoints has more than one epidemiologic study shown a statistically significant significant effect of ultrasound exposure?
a. fetal activity
b. birth weight
c. fetal abnormalities
d. dyslexia
e. none

A

e

102
Q

Which of the following acoustic parameters has (have) been documented in ultrasound epidemiologic studies published thus far?
a. frequency
b. exposure time
c. intensity and pulsing conditions
d. scanning patterns
e. none

A

e

103
Q

A device commonly used to measure the output of diagnostic ultrasound instruments is a(n) _____

A

hydrophone

104
Q

A typical output intensity (SPTA) for an ultrasound imaging instrument is

A

1 mW/cm2

105
Q

Which of the following typically has the highest output intensity?
a. fetal monitor Doppler
b. duplex pulsed Doppler
c. color- Doppler shift
d. color power Doppler
e. phase array, gray scale

A

b

PHYSICS (26 decks)

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