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Ultrasound Physics > Finals Part 2 > Flashcards

Finals Part 2 Flashcards

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1
Q

Under which of the following conditions is lateral resolution improved?

a. decreased beam diameter
b. decreased pulse duration
c. decreased imaging depth
d. decreased pixel size
e. decreased spatial pulse length

A

a. decreased beam diameter

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2
Q

In which way is an annular phase array transducer different than a linear phased array transducer?

a. the linear is steered mechanically
b. the linear can have multiple focal zones
c. the annular can create a sector shaped image
d. the linear has higher pulse repetition frequency
e. the annular is steered mechanically

A

e. the annular is steered mechanically

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3
Q

In which of these biologic tissues will sound waves p r o p a g a t e
most quickly?

a. tendon
b. blood
c. lung
d. fat
e. amniotic fluid

A

a. tendon

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4
Q

Which of the following best describes a sound beam?

a. electrical impulses
b. a collection of mechanical vibrations in the form of compressions and rarefactions
c. a wave that man can hear
d. electromechanical
e. ionic vibrations

A

a collection of mechanical vibrations in the form of compressions and rarefactions

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5
Q

You are performing a quality assurance study on an
ultrasound system using a
tissue equivalent phantom.
You make an adjustment using
a knob on the system console that changes the appearance
of reflector brightness from
fully bright to barely visible. What are you evaluating?

a. resolution
b. dynamic range
c. system sensitivity
d. vertical calibration
e. slice thickness

A

c. system sensitivity

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6
Q

Which of the following best describes the features of a sound wave and medium that determine the speed of sound in the medium?

a. density of the medium and stiffness of the medium
b. density of the medium and power of the sound beam
c. elasticity of the medium and frequency of the sound beam
d. stiffness of the medium and elasticity of the medium
e. pulse repetition period of the sound wave and density
of the medium

A

density of the medium and stiffness of the medium

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7
Q

while scanning in a water tank, what location in a sound beam has the highest intensity?

a. focal point
b. focal zone
c. Fresnel zone
d. Fraunhofer zone
e. half value depth

A

a. focal point

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8
Q

Which of these factors has
the greatest influence on pulse repetition period?

a. display depth
b. thickness of the PZT crystal
c. attenuation of the sound beam
d. impedance of the medium
e. display’s dynamic rang

A

a. display depth

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9
Q

Which of the following choices best describes an ideal
epidemiologic bioeffects study?

a. randomized and prospective
b. benefits outweigh the risks
c. retrospective and optimized
d. ideal and non-biased
e, prudent and safe

A

a. randomized and prospective

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10
Q

Which of the following will
result in the highest mechanical index?

a. high frequency and low power
b. high intensity and high frequency
.c low frequency and high signal amplitude
d. low intensity and low frequency

A

c. low frequency and high signal amplitude

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11
Q

Al of the following statements regarding in-vitro bioeffects are true EXCEPT:

a. In vitro bioeffects conclusions are clinically relevant
b. In vitro bioeffects are always real
.c In vitro bioeffects are very important
d. In vitro bioeffects may not
be applicable to clinical settings

A

a. In vitro bioeffects conclusions are clinically relevant

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12
Q

Under which circumstance is
the mechanical index highest?

a. high frequency and low p o w e r
b. high intensity and high frequency
c. low intensity and low frequency
d. low frequency and high signal amplitude

A

d. low frequency and high signal amplitude

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13
Q

Which of the following improves the signal-to-noise ratio?

a. dynamic range
b. frame averaging
c. gray scale
d. edge enhancement
e. receiver gain

A

b. frame averaging

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14
Q

Under which circumstance is cavitation most likely to occur?

a. high frequency and low power
b. high intensity and high frequency
c. low intensity and low
frequency
d. low frequency and high signal amplitude

A

d. low frequency and high signal amplitude

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15
Q

What is the accuracy of reflector depth position on an A-mode, B-mode or M-mode display called?

a. range resolution
b. horizontal calibration
c. axial resolution
d. s p e e d error artifact
e. depth calibration

A

e. depth calibration

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16
Q

Pre-processing occurs

a. when the patient is scanned
b. when images are transferred to the VCR
c. after the images are on the tape
d. when the image exits the
scan converter

A

a. when the patient is scanned

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17
Q

Post processing occurs when
the image

a. is played off o
f the VCR
b. entered the A/D converter
but before display
c. after ti leaves the A/D converter
d. after ti leaves the scan converter

A

b. entered the A/D converter
but before display

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17
Q

The region from the transducer to the minimum beam cross-sectional area is the

a. Fraunhofer zone
b. Fresnel zone
c. focus
d. Snell’s length

A

b. Fresnel zone

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18
Q

Biologic effects have not been documented below what intensity (SPTA)?

a. 100 W/cm
b. 100 mW/m2
c. 100 mW/cm2
d. 100 mW/cm3

A

c. 100 mW/cm2

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19
Q

What is the standard for communication between medical imaging computers?

a. ALARA
b. PACS
c. D-to- A conversion
d. DICOM
e. A-to-D conversion

A

d. DICOM

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20
Q

The Curie temperature has which
effect?

a. the backing material delaminates from the active element
b. the glue binding the crystal &matching layer melts
c. the ferroelectric material is depolarized
d. the matching layer changes its impedance

A

c. the ferroelectric material is depolarized

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21
Q

What happens to venous blood flow to the heart during expiration?
a. increased
b. decreased .
c unchanged

A

b. decreased

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22
Q

Which of the following has a propagation speed closest to “soft tissue”?

a. muscle
b. fat
.c bone
d. air

A

a. muscle

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23
Q

In a B-mode display, which of the following axes are used for
the amplitude of the
reflection?

a. Z-axis
b. m-axis
c. x-axis
d. y-axis
e. time base axis

A

a. Z-axis

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24
Q

What is displayed on the x-axis of an M-mode image?
a. time
b. time-of-flight
c.reflector depth
d. echo intensity
e. red blood cell velocity

A

a. time

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25
Q

What is displayed on the y
axis of an m-mode image?
a. time
b. time-of-flight
c. echo intensity
d. red blood cell velocity

A

b. time-of-flight

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26
Q

sonographer’s education ends when they become registered. T or F

A

F

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27
Q

The dynamic range is the ratio
of the smallest to the largest.
that a system can process without distortion.

a. amplitude
b. frequency
c. p h a s e delay
d. spatial length

A

a. amplitude

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28
Q

When may a patient revoke their consent to be treated?

a. at any time
b. when ti is safe to terminate the procedure
c. never

A

a. at any time

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29
Q

f the intensity
is increased by 3dB, it:

a. doubles
b. triples
c. halved
d. quartered

A

a. doubles

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30
Q

What determines the frequency of
a sound beam from a pulsed transducer?

a. voltage applied to the PZT
b. PZT thickness
c. frequency of the system
d. PRF of the pulser

A

b. PZT thickness

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31
Q

While propagating, a sound wave is refracted. Finally, it returns to the transducer. The system processes the sound wave as if it has:

a. refracted and returned
b. traveled in a straight line, reflected & returned
c. traveled in a straight line, attenuated, reflected & returned

A

traveled in a straight line, reflected & returned

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32
Q

What measures the output of a transducer?
a. receiver
b.display .
c hydrometer
d. hydrophone

A

d. hydrophone

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33
Q

The impedance of tissue is
3 x 105 rayls and for the PZT crystal is 6 x 106 rayls. What is the best impedance for the matching layer?

a. 63×106
b. 3,600
.с 10,000
d. 9.5 × 105
.e 9×104

A

d. 9.5 × 105

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34
Q

Put in increasing order of propagation speed:

a. air, bone, water
b. bone, water, air
c. air, water, bone
d. water, air, bone
e. bone, air, water

A

c. air, water, bone

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35
Q

Which type of artifact appears most commonly with highly reflective objects?

a. reverberations
b. mirroring
c. shadowing
d. enhancement
e. defocusing

A

c. shadowing

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36
Q

What can pulsed Doppler
measure that continuous wave cannot?

a. duration
D. speed
c. velocity
d. location
e. frequency

A

d. location

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37
Q

What is the fraction of time that a transducer is transmitting?

a. duty factor
b. pulse duration
c. period
d. PRF spatial duration

A

a. duty factor

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38
Q

Which of the following clinical modalities has the lowest output intensity?

a. pulsed Doppler
b. continuous wave Doppler
c. power Doppler
d. duplex scanning
e. gray scale imaging

A

e. gray scale imaging

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39
Q

What is the location of the minimum cross-sectional area of the US beam called?
a. focus
b. Fraunhofer zone .
c far zone
d. near zone

A

a. focus

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40
Q

The dB is defined as the of two intensities.

a. sum
b. diference
c. product
d. ratio

A

d. ratio

41
Q

I the power of a sound wave is increased by a factor of 8, how many decibels is this?

a. 3dB
b. 6dB
c. 9 ₫B
d. 8 dB

A

c. 9 ₫B

42
Q

An ultrasound system is set at O dB and is transmitting at full intensity. What is the output power when the system is transmitting at 50% of full intensity?

a. -3 dB
b. -50 dB
c. 10 dB
d. 3 dB
e. -10 dB

A

a. -3 dB

43
Q

An ultrasound
system is set at 0 dB and is transmitting at full intensity. What is the output power when the system is transmitting at 10% of full intensity?
a. 3- ₫b
b. -50 db
c. 40 dB
d. 3d8
e. -10 ₫b

A

e. -10 ₫b

44
Q

The Doppler shift is the of two frequencies.
a. sum
b. difference .
c product
d. ratio

A

b. difference

45
Q

What is propagation speed determined by?

a. wavelength
b. intensity & density
c. amplitude
d. density and elasticity
e. density and amplitude

A

d. density and elasticity

46
Q

If 300,000 cycles occur in a second, what is the waves frequency?

a. 3MHz
b. 30 kHz
c. 30 MHz
d. 3kHz
e. 0.3 MHz

A

e. 0.3 MHz

47
Q

What may be a unit of amplitude?
a. cm
b. HZ
c. msec
d. watts
e, none of the above

A

a. cm

48
Q

A Doppler exam is performed with a 5 MHz probe and a PRF of 15 kHz. Which of these Doppler shifts will create aliasing?

a. 2 kHz
b. 2.5 KHZ
c. 7 . 5 kHz
d. 14 kHz

A

d. 14 kHz

49
Q

Which of the following choices determines the signal amplitude in the transducer of an ultrasound system?

a. reflected intensity of the sound beam
b. post processing
c. edge enhancement filtering
d. persistence
e. demodulation

A

a. reflected intensity of the sound beam

50
Q

In an air-tissue interface, what percentage of the US si reflected?

a. 0%
b. near 0%
c 50%
d. near 100%

A

d. near 100%

51
Q

Traveling through the same medium, fi the frequency is doubled, the
wavelength is

a. unchanged
b. doubled
.c halved
d. quartered

A

c. halved

52
Q

Traveling through the same medium, if the frequency is doubled, the propagation speed is:

a .u n c h a n g e d
b. doubled
c. halved
d. quartered

A

a .u n c h a n g e d

53
Q

True or False. Increasing the frequency increases the penetration depth.

A

F

54
Q

True or False. Axial resolution
is affected by focusing.

A

False

55
Q

If a manufacturer changed the lines per frame and kept the imaging depth the same, what else would change?
a . PRF
b. period
.c frame rate

A

c. frame rate

56
Q

Which of the following has the greatest influence on temporal resolution?

a. propagation speed and the imaging depth
b. frequency of sound and the propagation speed
c. wavelength of sound & propagation speed
d. output power & frequency

A

a. propagation speed and the imaging depth

57
Q

In a real time scanner, which of these choices determines the maximum frame rate?

a. depth of view
b. pixel size
c. attenuation coefficient
d. beam diameter
e. lateral resolution

A

a. depth of view

58
Q

Multiple reflections that are equally spaced are called:

a. refractions
b. reverberations
c. shadows
d. comets

A

b. reverberations

59
Q

What artifact has a grainy appearance and is caused by the interference effects of scattered sound?

a. spackle
b. reverberation
c. slice thickness
d. speckle
e. section thickness

A

d. speckle

60
Q

Al of the following will
improve temporal resolution EXCEPT:

a. increased line density
b. single rather than multi focus
c. higher frame rate
d. shallower depth of view
e. slower speed of sound in a medium

A

a. increased line density

61
Q

Impedance is the product
of ——- a n d ———

A

Density, Propagation Speed

62
Q

The manufacturer increases the number of lines per frame. As a result, which of the following may have to be decreased?

a. frequency
b. frame rate
c. sector angle
d. imaging depth
e. power output

A

b. frame rate
c. sector angle
d. imaging depth

63
Q

What component of a
transducer changes electrical to mechanical and mechanical back to electrical energy?

A

PZT, Crystal

64
Q

Sonographers cannot affect
a patient’s exposure to acoustic energy.

A

False

65
Q

Attenuation of US in soft tissue
is closest to:

a. 3 dB/1MHz
b. 1 dB/cm/10MHz
c. 2 dB/ cm
d. 0.6 dB/cm/MHz

A

d. 0.6 dB/cm/MHz

66
Q

How many bits are needed to represent 1024 gray shades?

a. 1024
b. 8
c. 10
d. 3
e. 512

A

c. 10

67
Q

(True or False) Gray scale can be changed by the sonographer.

A

T

68
Q

The distance to a target is doubled. The time-of flight for a pulse to travel to the target and back is:

a. 4 times
b. 8 times
c. the same
d. 2 times

A

d. 2 times

69
Q

If 3MHz sound has 2dB of attenuation in 1cm of tissue,
what is the amount of
attenuation of 6MHz
sound in 0.5cm of the same
tissue?

a. 5dB
b. 2dB
c. 10 d B
d. 1.5dB

A

b. 2dB

70
Q

Volume has which of the following units?
a. cm
b. cm2
c. cm 3
d. cm 4

A

c. cm 3

71
Q

Which of the following is proportional to the square of the amplitude?

a. period
b. attenuation
c. power
d. frequency
e. speed

A

c. power

72
Q

What are typical clinical Doppler frequencies?

a. 1-10,000Hz
b. 1-10MHz
c. 2 - 1 , 0 0 0 k Hz
d. 40-45kHz

A

a. 1-10,000Hz

73
Q

What Doppler angle is most inaccurate?
a. 15-30 degrees
b. 30-45 degrees
c. 45-60 degrees
d. 60-75 degrees

A

d. 60-75 degrees

74
Q

Changing which of the
following would not cause any change in a hard copy image output?

a. TGC
b. overall gain
c. output power
d. display brightness & contrast
e. depth of view

A

d. display brightness & contrast

75
Q

A quality assurance program:

a. is not needed in small labs
b. is very time consuming and expensive
c. is needed by all labs
d. cannot be
performed by sonographers

A

c. is needed by all labs

76
Q

What is the actual time that an US machine is creating a pulse?

a. duty factor
b. period
c. pulse period
d. pulse duration

A

d. pulse duration

77
Q

The angle of incidence of an US beam is perpendicular to an interface. The two media have the same propagation speeds. What process cannot occur?

a. refraction
b. reflection
c. transmission
d. attenuation

A

a. refraction

78
Q

What component of the US unit contains the memory bank?

a. transducer
b. receiver
c. display
d. scan converter

A

d. scan converter

79
Q

An US wave travels through two media and has attenuation of 3 dB in the first and 5 dB in the second. What is the total attenuation?

a. 15 dB
b. 8 dB
c. 3 / 5 dB
d. 5/8 dB

A

b. 8 dB

80
Q

According to the AIUM
statement on bioeffects, there have been no confirmed bioeffects below intensities of watts per square centimeter SPTA.

a. 10
b. 0.01
c. 0.1
d.1
e.1 0 0

A

c. 0.1

81
Q

Fill-in of an anechoic structure s u c h as a cyst is known as all of the following EXCEPT?

a. partial volume artifact
b. slice thickness artifact
c. section thickness artifact
d. ghosting artifact

A

d. ghosting artifact

82
Q

What si the range of frequencies created by medical diagnostic Doppler transducers?

a. 4-10Hz
b. 10-20MHz
c. 1-10 kHz
d. 2-20Hz
e. 2 - 10MHz

A

e. 2 - 10MHz

83
Q

(True or False) Doppler shifts
are always created when the
source and receiver are in motion relative to each other.

A

False

84
Q

What is the significance of gray scale variation in the spectrum of a pulsed wave Doppler display?

a. it represents the number of
red blood cells creating the reflection
b. it represents the velocity of red blood cells
c. it represents the speed of red blood cells
d. it represents the convergence of red blood cell lamina
e. ti determines the ensemble length

A

it represents the number of
red blood cells creating the reflection

85
Q

Which one of the following sets of properties of a test phantom is most relevant when assessing depth calibration accuracy?

a. reflector spacing and reflection coefficient
b. attenuation and speed of US in the medium
c. reflector spacing and US attenuation in the medium d. reflector reflection coefficient and US attenuation in the medium
e. reflector spacing and propagation speed

A

e. reflector spacing and propagation speed

86
Q

From a safety stand point, which of the following methods is best?

a. low transmit output and high receiver gain
b. high transmit output and low receiver gain
c. high near gain and low far gain
.d low near gain and high far gain
e. high reject and high transmitter output

A

a. low transmit output and high receiver gain

87
Q

The relative output of an US instrument is calibrated in dB and the operator increases the output by 60 dB. The beam intensity is increased by which of the following?

a. 5%
b. two times
.c twenty times
d. one hundred times
e. one million times

A

e. one million times

88
Q

What is the most typical Doppler shift measured clinically?

a. 3.5MHz
b. 3,500,000Hz .
c 2kHz
d. 1,000kHz
e. 20,000Hz

A

c 2kHz

89
Q

(True or False) Doppler shifts always occur fi the source and receiver are in motion relative to each other.

A

False

90
Q

(True or False) Doppler shifts always occur fi the source and observer are in motion relative to each other and the angle between the mo
tion and the sound beam is 90°.

A

False

91
Q

(True or False) Doppler shifts always occur fi the source and observer are in motion relative to each other and the angle between the motion and the sound beam is not 90 degrees.

A

True

92
Q

When the sound source and
the receiver are not moving directly toward or away from each other, the angle b e t w e e n t h e m enters
into the calculation of Doppler shift.

a. average
b. slope
c. sine
.d cosine

A

.d cosine

93
Q

The range equation relates distance from the reflector
to ——and ——-

a. time-of-flight, distance
b. frequency, wavelength
c. time-of-flight, propagation speed
d. propagation speed, density

A

c. time-of-flight, propagation speed

94
Q

In soft tissue:
Distance traveled =
———- *round trip time

.a propagation speed
b. wavelength
.c period
d. PRF

A

a. propagation speed

95
Q

What is another name for
longitudinal resolution?

a. axial
b. Depth
c. Lateral
d. Transverse

A

a. axial
b. Depth

96
Q

With the presence of—— we see more boundaries than there are reflecting surfaces.

a. reverberations
b. shadowing
c. enhancement
d. arrays

A

a. reverberations

97
Q

What is the name of the
receiver function that corrects
for attenuation?

A

Compensation

98
Q

The process of reducing the difference between the
smallest and largest voltages
is called

A

Compression

99
Q

If the lines per frame is
increased while the imaging
depth is unchanged then:

a. frame rate increases
b. number of shades of gray decreases
.c the frame rate decreases
d. this cannot happen

A

c. the frame rate decreases

Ultrasound Physics (11 decks)

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