Comprehensive Exam Flashcards
(187 cards)
0
Q
The speed of u/s in soft tissue is closest to: A. 1,540km/sec B. 1.54km/msec C. 1,500m/s D. 1,540mm/sec
A
C
1
Q
Sound waves are: A. Electric B. mechanical, transverse C. Spectral D. Longitudinal, mechanical
A
D
2
Q
The frequency closest to the lower limit of u/s is A. 19,000kHz B. 10,000MHz C. 20,000msec D. 15,000Hz
A
D
3
Q
Which is not an acoustic variable? A. Density B. pressure C. Distance D. Intensity
A
D
4
Q
The effects of soft tissue on u/s are called A. Acoustic proliferation properties B. dynamic effects C. Acoustic propagation properties D. Biological effects
A
C
5
Q
All of the following are true except:
A. Two waves with identical freq must interfere constructively
B. constructive interference is associated with waves that are in-phase
C. Out-of-phase waves interfere destructively
D. Waves of different freq may exhibit both constructive and destructive interference at different times
A
A
6
Q
Put in decreasing order A. Deca B. deci C. Micro D. Centi
A
A b d c
7
Q
----- is the time to complete one cycle A. Pulse duration B. pulse period C. Period D. Duration period
A
C
8
Q
Which of the following sound waves is ultrasonic and least useful in diagnostic imaging? A. 30 kHz B. 8 MHz C. 8,000 Hz D. 3,000 kHz E. 15 Hz
A
A
9
Q
What is the freq of a wave with 1 msec period? A. 10,000 Hz B. 1,000 kHz C. 1 kHz D. 1 MHz
A
C
10
Q
----- is the distance covered by one cycle. A. Pulse length B. wavelength C. Cycle distance D. Cycle duration
A
B
11
Q
Which of the following is determined by the sound source and the medium? A. Frequency B. period C. Propagation speed D. Range resolution
A
D
12
Q
Propagation speed =\_\_\_\_ x wavelength A. Pulse duration B. period C. Number of cycles in pulse D. Frequency
A
D
13
Q
As a result of ____ the propagation speed increases.
A. Increasing stiffness and increasing density
B. increasing stiffness and increasing elasticity
C. Decreasing compressibility and decreasing density
D. Decreasing stiffness and decreasing density
A
C
14
Q
Put in decreasing order of propagation speed
A. Gas
B. liquid
C. Solid
A
C b a
15
Q
If the frequency of u/s is increased from 0.77MHz to 1.54MHz, what happens to the wavelength? A. Doubles B. halved C. Remains same D. 4 times greater
A
B
16
Q
A sound wave's frequency is 10MHz. The wave is traveling in soft tissue. What is it's wavelength? A. 0.15 mm B. 1.54 mm C. 0.77 mm D. 10 MHz
A
A
17
Q
If the frequency of an u/s wave is doubled, what happens to the period? A. Doubles B. halved C. Remains same D. 4 times greater
A
B
18
Q
If the frequency of u/s is increased from 0.77 MHz to 1.54 MHz. What happens to the propagation speed? A. Doubles B. halved C. Remains same D. 4 times greater
A
C
19
Q
The units of pulse repetition frequency are A. Per minute B. Msec C. mm/us D. MHz
A
A
20
Q
The time from the beginning of a pulse until it's end is \_\_\_? A. Period B. pulse duration C. Pulse length D. PRF
A
B
21
Q
What happens to the speed of sound in a medium when the bulk modulus of the medium increases?
A. Faster
B. slower
C. Unchanged
A
A
22
Q
\_\_\_\_ resolution is determined by the spatial pulse length. A. Radial B. image C. Axial D. Angular
A
A or c
23
Q
If a waves amplitude is doubled, what happens to the power? A. Nothing B. halved C. Doubled D. Quadrupled
A
D
24
```
Power of sound has units of
A. dB
B. dB/cm
C. Watts
D. Watts/cm2
```
C
25
```
If the intensity of a sound beam remains unchanged while the beam area is reduced in half, what has happened to the power?
A. Quadrupled
B. doubled
C. Halved
D. Unchanged
```
C
26
Which of these intensities is smallest?
A. SATP
B. SPTP
C. SATA
C
27
```
The duty factor for continuous wave u/s is
A. 10.0
B. 1%
C. 1.0
D. 0.0%
```
C
28
```
What is the minimum value of the duty factor?
A. 10.0
B. 1%
C. 1.0
D. 0.0
```
D
29
```
What are the units of intensity?
A. Watts
B. dB
C. Watts/cm2
D. dB
```
C
30
What happens to the speed of sound in a medium when the bulk modulus of the medium decreases?
A. Faster
B. Slower
C. Unchanged
B
31
```
The units of attenuation are ___; this is a ____ scale.
A. mm/cm, parametric
B. dB/m, multiplicative
C. None, relative
D. dB, logarithmic
```
D
32
```
Sound intensity is decreased by 75%. How many decibels of attenuation is this?
A. 6 dB
B. 9 dB
C. 5 dB
D. 10 dB
```
A
33
```
The fundamental frequency of a transducer is 2.5 MHz. What is the second harmonic frequency?
A. 1.25 MHz
B. 4.5 MHz
C. 5 MHz
D. 5 cm
```
C
34
```
A pulse is emitted by a transducer and is traveling in soft tissue. The go-return time, or time of flight, of a sound pulse is 130 microseconds. What is the reflector depth?
A. 10cm
B. 10 mm
C. 10 m
D. 130 mm
E. 13 cm
```
A
35
```
If a 5 MHz sound wave is traveling in the tissues listed below, which will have the longest wavelength?
A. Fat
B. Air
C. Muscle
D. Bone
```
D
36
```
If a 5 MHz sound wave is traveling in the tissues listed below, which will have the shortest wavelength?
A. Fat
B. Air
C. Muscle
D. Bone
```
B
37
```
What is the approximate attenuation coefficient of 1 MHz u/s in soft tissue?
A. 0.5 dB/cm
B. 1 cm
C. 3 dB/cm
D. 1 dB
```
A
38
```
The rayl is the unit of:
A. Intensity
B. Reflectance
C. Density
D. Impedance
```
D
39
```
Impedance is the ____ of ____ and ___.
A. Product, propagation speed, density
B. Sum, stiffness, density
C. Quotient, stiffness, propagation speed
D. Difference, attenuation, density
```
A
40
What are attenuations three components?
Scattering
Reflection
Absorption
41
```
For soft tissue, the approximate attenuation coefficient in dB/cm is equal to one-half ____ in ____.
A. Wavelength, mm
B. Frequency, Hz
C. Frequency, MHz
D. Impedance, Rayls
```
C
42
```
As the impedance of two media become vastly different, the
A. Reflection increases
B. Transmission increases
C. Refraction increases
D. Absorption increases
```
A
43
```
The angle between an u/s pulse and the boundary between two media is 90' . What is this called?
A. Direct incidence
B. Oblique incidence
C. Indirect incidence
D. Orthogonal incidence
```
D
44
```
The angle between an u/s pulse and the boundary between two media is 56'. What is this called?
A. Direct incidence
B. Oblique incidence
C. Indirect incidence
D. Orthogonal incidence
```
B
45
Refraction only occurs if there are:
A. Normal incidence & different impedances
B. Indirect intensity & different propagation speeds
C. Oblique incidence & different propagation speeds
D. Oblique frequency & identical impedances
C
46
```
With normal incidence, what factors affect refraction of u/s?
A. Propagation speeds
B. Frequencies
C. Attenuation coefficients
D. None of the above
```
D
47
(True or false) with right angle incidence, reflections are always generated at a boundary if the propagation speeds of the media are different
False
48
```
____ is redirection of u/s in many directions as a result of rough boundary between two media.
A. Refraction
B. Rayleigh scattering
C. Scattering
D. Reflection
```
C
49
```
Which of the following tissues is most likely to create Rayleigh scattering?
A. Red blood cells
B. Muscle
C. Fat
D. Bone
```
A
50
(True or false) with normal incidence the angle is 180'
False
51
```
Under which of the following conditions is axial resolution improved?
A. Decrease spatial pulse length
B. Decrease pulse amplitude
C. Decreased imaging depth
D. Decrease pixel size
E. Decrease beam diameter
```
A
52
```
Snell's law describes physics of _____.
A. Ultrasound
B. Reflection
C. Refraction
D. Transmission
```
C
53
```
The most likely amount of reflection at a boundary between soft tissues is:
A. 1%
B. 22%
C. 34%
D. 99%
```
A
54
```
The most typical amount of transmission at a boundary and biological media is:
A. 1%
B. 22%
C. 34%
D. 99%
```
D
55
Sound is traveling from medium 1 to medium 2. Propagation speeds of M1 and M2 are 1,600 m/s and 1,500 m/s, respectively. there is normal incidence.
A. angle of incidence > angle of reflection
B. angle of incidence = angle of reflection
C. angle of incidence
B
56
(true or false) Doppler shifts always occur if the sound source and receiver are in motion
False
57
The following is associated with power mode Doppler?
A. poor temporal resolution and flash artifact
B. lower sensitivity and good temporal resolution
C. high sensitivity and high frame rates
D. flash artifact and reduce sensitivity
E. good temporal resolution and flash artifact
A
58
The doppler shift is a measure of:
A. ratio of incident frequency to reflector frequency
B. sum of incident frequency and reflected frequency
C. difference between incident and reflected frequency
D. product of incident and reflected frequencies
C
59
(true or false) the sonographer cannot change, directly or indirectly, the duty factor of an u/s machine
False
60
(true or false) there have not been biological effects from u/s found in the laboratory
False
61
```
Depth calibration of the machine measures 100mm spaced wires to be 90mm apart. Scanning reflectors 50mm apart. what will the machine calculate the distance to be?
A. 40 mm
B. 45 mm
C. 60 mm
D. 65 mm
```
B
62
```
what has the correct order?
Mega- milli- kilo- micro
A. 10^6 10^-6 10^3 10^-3
B. 10^-6 10^6 10^2 10^-3
C. 10^6 10^-3 10^3 10^-6
D. 10^6 10^-6 10^3 10^-4
```
C
63
```
How many cm are 60 millimeters?
A. 600
B. 6
C. 0.6
D. 0.06
```
B
64
(true or false) lateral resolution is also called axial
False
65
(true or false) lateral resolution is also called azimuthal
True
66
(true or false) lateral resolution is also called longitudinal
False
67
(true or false) lateral resolution is also called range
False
68
```
which has the correct units?
freq speed intens atten
A. Hz mm/s joules dB/cm
B. mHz m/sec W/cm2 dB
C. kHz mm/us W/cm3 dB/cm
```
B
69
```
What increases patient exposure?
A. exam time
B. frequency
C. video taping
D. wavelength
```
A
70
(true or false) Shadowing may result from high amounts of reflection of u/s energy.
True
71
```
Where are harmonics created?
A. in the receiver
B. in the transducer
C. in the tissues
D. in the beam former
```
C
72
```
How is range ambiguity artifact eliminated?
A. lower PRF
B. raise PRF
C. increase gain
D. use lower frequency transducer
```
A
73
how is lateral resolution measured if this test object is scanned from the top
Pin Image
A * ____
B * __
C * ______
D * _________
E * ____________
A. measure the distance from A to E
B. measure the length of time of line C and divide by 2
C. measure the length of line B
C
74
```
how is lateral resolution measured if this test object is scanned from the top
Pin Image
A * ____
B * __
C * ______
D * _________
E * ____________
```
A. measure the distance from A to E
B. measure the length of time of line C and divide by 2
C. measure the length of line B
C
75
```
which transducer would be best to image superficial strutters?
A. small diameter, high frequency
B. small diameter, low frequency
C. large diameter, high frequency
D. large diameter, low frequency
```
A
76
```
A transducer with more than one active element is called:
A. multipurpose
B. annular
C. mechanical
D. array
```
D
77
```
how many bits are needed to represent 16 shades of gray?
A. 2
B. 3
C. 4
D. 5
```
C
78
```
What information does doppler shift provide?
A. flow
B. cardiac output
C. velocity
D. speed
```
C
79
(true or false) a sound wave is a pressure wave made of compressions and rarefractions.
True
80
```
A hydrophone is used to measure
A. velocity
B. Frequency
C. Intensity
D. phase
```
C or B
81
```
Images on video tape are stored using:
A. magic
B. magnetism
C. paper
D. computer memory
```
B
82
```
Circumferences may be measured in units of:
A. cm
B. cm squared
C. cubic cm
D. cubits
```
A
83
```
Decimal uses a base of 10, binary uses a base of
A. 1
B. 2
C. 5
D. 10
```
B
84
```
If the frame rate increases and the lines per frame is unchanged, what else must happen?
A. u/s speed increases
B. frequency increases
C. depth increases
D. depth decreases
```
D
85
```
Which of these cannot be performed by a sonographer?
A. adjust overall gain
B. clean VCR recording heads
C. clean pixels
D. adjust time gain compensation
```
C
86
```
which of the following is not a beam steering technique for a mechanical scan head?
A. rotating wheel
B. phased beam
C. oscillating disc
D. oscillating mirror
```
B
87
(true or false) A system which was working well now does not display clear images in the far field. this may be a problem with the transducer
True
88
(true or false) A system which was working well now does not display clear images in the far field. this may be a problem with the receiver
True
89
(true or false) A system which was working well now does not display clear images in the far field. this may be a problem with the monitor
True
90
(true or false) A system which was working well now does not display clear images in the far field. this may be a problem with the scan converter
True
91
```
Which has the greatest amount of attenuation?
A. bone
B. fat
C. water
D. muscle
```
A
92
```
which of the following will result in the greatest number of shades of gray in a digital image display?
A. large pixels with many bits/pixel
B. small pixels with few bits/pixel
C. many TV lines per frame
D. high contrast
E. narrow dynamic range
```
A
93
```
what is not the responsibility of the sonographer?
A. clean filters
B. adjust the recorder
C. adjust converter matrix
D. change paper
```
C
94
```
with good images on the display but not the printer, one should
A. increase the gain
B. adjust the recorder
C. check the scan converter
D. adjust the recorder
```
D
95
```
To measure the u/s beam intensity, use a
A. calibrated hydrophone
B. lateral oscilloscope
C. water filled phantom
D. tissue equivalent phantom
```
A
96
```
when the u/s machine displays only strong reflecting objects and nothing else, the sonographer should
A. adjust far gain
B. increase output power
C. increase lateral resolution
adjust TGC
```
B
97
compression is used to
A. decrease the amplitude
B. decrease the range of amplitudes
C. decrease the range of frequencies
B
98
Reject is used to
A. alter the appearance of highly reflective objects
B. alter the appearance of lowly reflective objects
C. improve axial resolution
D. improve digital scan converter sensitivity
B
99
```
If a reflector is moved as far away from the transducer, how will this affect the time-of-flight of a sound pulse?
A. quadruple it
B. double it
C. no change
D. halve it
```
B
100
```
A single element transducer is focused
A. by the manufacture
B. cannot be focused
C. by increasing the power
D. by the sonographer
```
A
101
```
An u/s machine has digital scan converter but has an analog input signal. the machine needs to have a
A. hybrid multiplexer
B. a modem
C. analog to digital converter
D. digital monitor
```
C
102
```
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. decrease spatial pulse length
```
A
103
in which way is an annular phase array transducer different than a linear phased array transducer?
A. the linear is steered
B. the linear can have multiple focal zones
C. the annular can create a rectangular shaped image
D. the linear had higher pulse repetition frequency
E. the annular is steered mechanically
E
104
```
in which of these biologic tissues will sound waves propagate most quickly?
A. tendon
B. blood
C. lung
D. fat
E. amniotic fluid
```
A
105
which of the following best describes a sound beam?
A. electrical impulses
B. a collection of mechanical vibrations in the form of compressions and rare fractions
C. a wave that man can hear
D. electromechanical variations
E. ionic vibrations
B
106
```
you are performing a quality assurance study on an u/s 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
```
C
107
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
108
```
While scanning in a water tank, what location in a sound beam has the highest intensity?
A. focal point
B. focal zone
C. frensel zone
D. Fraunhofer zone
E. half value depth
```
A
109
```
Which of these factors has the greatest influence on pulse repeton period?
A. display depth
B. thickness of the PZT crystal
C. attenuation of the sound beam
D. imprudence of the medium
E. display's dynamic range
```
A
110
```
which of the following choices best describes an ideal epidermiologic bioeffects study?
A. randomized and prospective
B. benefit outweigh the risks
C. retrospective and optimized
D. ideal and non-biased
E. prudent and safe
```
A
111
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
C
112
All 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
113
Under which circumstance is a mechanical index lowest?
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
114
```
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
```
B
115
under which circumstance is cavitation most likely to occur?
A. high frequency and low power
B. high intensity and high frequency
C. low intensity ad low frequency
D. low frequency and high signal amplitude
D
116
```
where does coded excitation originate?
A. in the receiver
B. in the tissues
C. in contrast agents
D. in the matching layer
E. in the pulser
```
E
117
pre-proccessing 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 exists the scan converter
A
118
```
post processing occurs when the image
A. is played off of the VCR
B. entered the A/D converter but before display
C. after it leaves the A/D converter
D. after it leaves the scan converter
```
B
119
```
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
```
B
120
```
biological 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
```
C
121
```
what is the standard for communication between medical imaging computers?
A. ALARA
B. PACS
C. D-to-A conversion
D. A-to-D conversion
```
D
122
The curie temperatures has which effects?
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
C
123
what happens to venous return to the heart during expiration?
A. increased
B. Decreased
C. increased
B
124
```
which of the following has propagation speed closest to "soft tissue"?
A. muscle
B. fat
C. bone
D. air
```
A
125
```
when can a patient revoke consent?
A. at any time
B. before the procedure begins
C. never
D. only prior to sedation
```
A
126
```
which of the following does not change temporal resolution
A. frequency compounding
B. persistance
C. spatial compounding
D. temporal resolution
```
A
127
```
which of the following is not preprocessing?
A. write magnification
B. 3-D rendering
C. fill-in interpolation
D. spatial compounding
```
B
128
(true or false) A sonographer's education ends when they become registered.
False
129
```
The dynamic range is the ratio of the smallest to the largest _____ that a system can process without distortion
A. amplitude
B. frequency
C. phase delay
D. spatial length
```
A
130
when may a patient revoke their consent to be treated?
A. at any time
B. when it is safe to terminate the procedure
C. never
A
131
```
if the intensity is increased by 3 dB, it:
A. doubles
B. triples
C. halved
D Quartered
```
A
132
```
what determines the frequency of a sound beam form a pulsed transducer?
A. voltage applied to the PZT
B. PZT thickness
C. frequency of the system
D. PRF of the pulser
```
B
133
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
B
134
```
what measures the output of a transducer?
A. receiver
B. display
C. hydrometer
D. hydrophone
```
D
135
```
the impedance of tissue is 3 x 10^5 rayls and for the PZT crystal is 6 x 10^6 rayls. what is the best impedance for the matching layer?
A. 36 x 10^6
B. 3,600
C. 10.000
D. 9.5 x 10^5
E. 9 x 10^4
```
D
136
```
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
```
C
137
```
Which type of artifact appears most commonly with highly reflective objects?
A. reverberations
B. mirroring
C. shadowing
D. enhancement
E. defocusing
```
C
138
```
what can pulsed doppler measure that continuous wave cannot?
A. duration
B. speed
C. velocity
D. location
E. frequency
```
D
139
```
what is the fraction of time that a transducer is transmitting?
A. duty factor
B. pulse duration
C. period
D. PRF spatial duration
```
A
140
```
which if 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
```
E
141
```
what is the location of the minimum cross-sectional area of the u/s beam called?
A. focus
B. fraunhofer zone
C. far zone
D. near zone
```
D
142
```
the dB is identified as the ____ of two intensities.
A. sum
B. difference
C. product
D. ratio
```
D
143
```
an u/s system is set at 0 dB and is transmitting at full intensity. what is the power 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
144
```
an u/s 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 dB
B. -50dB
C. 40 dB
D. 3 dB
E. -10 dB
```
E
145
```
the doppler shift is the ____ of two frequencies.
A. sum
B. difference
C. product
D. ratio
```
B
146
```
what is propagation speed determined by?
A. wavelength
B. intensity & density
C. amplitude
D. density and elasticity
E. density and amplitude
```
D
147
```
if 300,000 cycles occur in a second. what is the waves frequency?
A. 3vMHz
B. 30 kHz
C. 300 MHz
D. 3 kHz
E. 0.3 MHz
```
E
148
where is the most intensity in a beam
focus
149
```
what may be a unit of amplitude?
A. cm
B. Hz
C. msec
D. watts
E. none of the above
```
A
150
```
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
```
D
151
```
which of the following choices determines the signal to amplitude in the transducer of an u/s system?
A. reflected intensity of the sound beam
B. post processing
C. edge enhancement filtering
D. persistance
E. demodulation
```
A
152
```
in an air-tissue interface, what percentage of the u/s is reflected?
A. 0%
B. near 0%
C. 50 %
D. near 100%
```
D
153
```
traveling through the same medium, if the frequency is doubled, the wavelength is:
A. unchanged
B. doubled
C. halved
D. quartered
```
C
154
```
traveling through the same medium, if the frequency is doubled, the propagation speed is:
A. unchanged
B. doubled
C. halved
D. quartered
```
A
155
(true or false) increasing the frequency increases the penetration depth
False
156
(true or false) axial resolution is affected by focusing
False
157
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
C
158
which of the following has the greatest influence on temporal resolution?
A. propagation speed and imaging depth
B. frequency of sound and the propagation speed
C. wavelength of sound and propagation speed
D. output power and frequency
A
159
```
in a real time scanner, which of these choices determines the maximum frame rate?
A. depth of view
B. pixel size
C. beam diameter
D. lateral resolution
```
A
160
```
multiple reflections that are equally spaced are called:
A. refractions
B. reverberations
C. shadows
D. comets
```
B
161
```
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
```
D
162
```
all of the following will improve temporal resolution except:
A. increase 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
163
impedance is the product of ____ and ____.
density and propagation speed
164
(true or false) the manufacturer increases the number of lines per frame. As a result, frequency is decreased.
False
165
(true or false) the manufacturer increases the number of lines per frame. As a result, frame rate is decreased.
True
166
(true or false) the manufacturer increases the number of lines per frame. As a result, sector angle is decreased.
True
167
(true or false) the manufacturer increases the number of lines per frame. As a result, imaging depth is decreased.
True
168
(true or false) the manufacturer increases the number of lines per frame. As a result, power output is decreased.
False
169
what componant of a transducer changes electrical to mechanical and mechanical back to electrical energy?
PZT
170
(true or false) sonographers cannot affect a patients exposure to acoustic energy.
False
171
```
attenuation of u/s in soft tissue is closest to:
A. 3 dB/1MHz
B. 1 bD/cm/10MHz
C. 2 dB/cm
D. 0.6 dB/cm/MHz
```
D
172
```
how many bits are needed to represent 1024 gray shades
A. 1024
B. 8
C. 10
D. 3
E. 512
```
C
173
(true of false) gray scale can be changed by sonographer
True
174
```
the distance to a target is doubled. the time-to-fight for a pulse to travel to the target and back is
A. 4 times
B. 8 times
C. the same
D. 2 times
```
D
175
```
volume has which of the following units?
A. cm
B. cm2
C. cm3
D. cm4
```
C
176
```
which of the following is proportional to the square of the amplitude?
A. period
B. attenuation
C. power
D. frequency
E. speed
```
C
177
```
what are typical clinical doppler frequencies?
A. 1-10,000Hz
B. 1-10MHz
C. 2-1,000 kHz
D. 40-45kHz
```
A
178
```
what doppler angle is most inaccurate?
A. 15-30 degrees
B. 30-45 degrees
C. 45-60 degrees
D. 60-75 degrees
```
D
179
```
changing which of the following wouldn't 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
```
D
180
```
a quality assurance program:
A. is not needed in small labs
B. is very time consuming and expensive
C. is needed in all labs
D. cannot be performed by the sonographer
```
C
181
```
what is the actual time that an u/s machine is creating a pulse?
A. duty factor
B. period
C. pulse period
D. pulse duration
```
D
182
```
the angle of incidence of an u/s beam is perpendicular to an interference. the two media have the same propagation speeds. what process cannot occur?
A. refraction
B. reflection
C. transmission
D. attenuation
```
A
183
```
what component of the u/s unit contains the memory bank?
A. transducer
B. receiver
C. display
D. scan converter
```
D
184
```
an u/s wave travels through two media and has attenuation of 3dB in the first and 5dB in the second. what is the total attenuation?
A. 15dB
B. 8dB
C. 3/5 dB
D. 5/8 dB
```
B
185
```
according to the AIUM statement of 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. 100
```
C
186
```
fill-in of an anechoic structure such as a cyst is known as all the following EXCEPT?
A. partial volume artifact
B. slice thickness artifact
C. section thickness artifact
D. ghosting artifact
```
D
