Questions Flashcards
Sound wave are
a. electric
b. mechanical, transverse
c. spectral
d. longitudinal, mechanical
longitudinal, mechanical
The speed of US in soft tissue is closest to:
a. 1,540 km/sec
b. 1.54 km/msec
c. 1,500 m/s
d. 1,540 mm/sec
1,500 m/s
The frequency closest to the lower limit of US is:
a. 19,000 kHz
b. 10,000 MHz
c. 20,000 msec
d. 15,000Hz
15,000 HZ
Which is not an acoustic variable?
a. density
b. pressure
c. distance
d. intensity
intensity
The effects of soft tissue on US are called:
a. acoustic proliferation properties
b. dynamic effects
c. acoustic propagation properties
d. biologic effects
acoustic propagation properties
All of the following are true except:
a. two waves with identical frequencies 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 frequencies may exhibit both constructive and destructive interference at different times.
two waves with identical frequencies must interfere constructively
Put in decreasing order:
a. deca
b. deci
c. micro
d. centi
deca
deci
centi
micro
_________ is the time to complete one cycle.
Period
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. 15 Hz
30 KHz
What is the frequency of a wave with 1 msec period?
a. 10,000 Hz
b. 1,000 kHz
c. 1 kHz
d. 1 MHz
1 kHz
_____ Is the distance covered by one cycle.
wavelength
Which of the following is determined by the source and medium?
a. frequency
b. period
c. propagation speed
d. range resolution
range resolution
Propagation speed = _____ X wavelength
frequency
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
decreasing compressibility and decreasing density
Put in decreasing order of propagation speed:
a. gas
b. liquid
c. solid
solid
liquid
gas
If the frequency of US is increased from 0.77 MHz to 1.54MHz, what happens to the wavelength?
a. doubles
b. halved
c. remains the same
d. 4 times greater
halved
A sound waves frequency is 10 MHz. The wave is traveling in soft tissue, what is the wavelength?
a. 0.15 mm
b. 1.54 mm
c. 15.4 mm
d. 0.77 mm
e. 10 MHz
0.15 mm
If the frequency of an US wave is doubled, what happens to the period?
a. doubled
b. halved
c. remains the same
d. 4 times greater
halved
If the frequency of US is increased from 0.77 MHz to 1.54MHz, what happens to the propagation speed?
a. doubles
b. halved
c. remains the same
d. 4 times greater
remains the same
The units of pulse repetition frequency are?
a. per minute
b. msec
c. mm/microsec
d. MHx
per minute
The time from the beginning of a pulse until its end is _______.
pulse duration
What happens to the speed of sound in a medium when the bulk modules of the medium increases?
a. faster
b. slower
c. unchanged
faster
_______ resolution is determined by the spatial pulse length.
radial or axial
If a waves amplitude is doubled, what happens to the power?
a. nothing
b. halved
c. doubled
d. quadrupled
quadrupled
If the level of an acoustic variable ranges from 55 to 105, what is the amplitude?
a. 105
b. 50
c. 25
d. 55
25
Power of sound has units of?
watts
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
halved
Which of these intensities is smallest?
a. SATP
b. SPTP
c. SATA
SATA
The duty factor for continuous wave ultrasound is?
a. 10.0
b. 1%
c. 1.0
d. 0.0%
1.0
What is the minimum value of the duty factor?
a. 10.0
b. 1%
c. 1.0
d. 0.0%
0.0%
What are the units of intensity?
watts/cm^2
What happens to the speed of sound in a medium when the bulk modules of the medium decrease?
a. faster
b. slower
c. unchanged
slower
The units of attenuation are _____; this is a _____ scale.
a. mm/cm, parametric
b. dB/m, multiplicative
c. none, relative
d. dB, logarithmic
dB, logarithmic
Sound intensity is decreased by 75%. How many decibels of attenuation is this?
a. 6 dB
b. 9dB
c. 5 dB
d. 10dB
6dB
The fundamental frequency of a transducer is 2.5MHz. What is the second harmonic frequency?
a. 1.25 MHz
b. 4.5 MHz
c. 5 MHz
d. 5cm
5 MHz
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. 10mm
c. 10m
d. 130mm
e. 13cm
10cm
If a 5MHz sound wave is traveling in the tissues listed below, which will have the longest wavelength?
a. fat
b. air
c. muscle
d. bone
bone
If a 5MHz sound wave is traveling in the tissues listed below, which will have the shortest wavelength?
a. fat
b. air
c. muscle
d. bone
air
What is the approximate attenuation coefficient of 1 MHz US in soft tissue?
a. 0.5 dB/cm
b. 1 cm
c. 3 dB/cm
d. 1 dB
0.5 dB/cm
The rayl is the unit of:
impedance
Impedance is the _____ of ______ and _______.
a. product, propagation speed, density
b. sum, stiffness, density
c. quotient, stiffness, propagation speed
d. difference, attenuation, density
product, propagation speed and density
What are attenuation’s three components?
scattering, reflection and absorption
For soft tissue, the approximate attenuation coefficient in db/cm is equal to one-half ____ in ______.
a. wavelength, Hz
b. frequency, Hz
c. frequency, MHz
d. impedance, rayls
frequency, MHz
As the impedances of two media become vastly different, the
a. reflection increases
b. transmission increases
c. refraction increases
d. absorption increases
reflection increases
The angle between an US pulse and the boundary between two media is 90 degrees. What is this called?
a. direct incidence
b. oblique incidence
c. indirect incidence
d. orthogonal incidence
orthogonal incidence
The angle between an US pulse and the boundary between two media is 56 degrees. What is this called?
a. direct incidence
b. oblique incidence
c. indirect incidence
d. orthogonal incidence
oblique incidence
Refraction only occurs if there are:
a. normal incidence and different impedances
b. indirect intensity and different propagation speeds
c. oblique incidence and different propagation speeds
d. oblique frequency and identical impedances
oblique incidence and different propagation speeds
With normal incidence, what factors affect refraction of US?
a. propagation speed
b. frequencies
c. attenuation coefficients
d. none of the above
none of the above
(True or False) With right angle incidence, reflections are always generated at a boundary if the propagation speeds of the media are different.
false
____ is a reduction of US in many directions as a result of a rough boundary between two media.
a. refraction
b. Rayleigh scattering
c. scattering
d. reflection
scattering
Which of the following tissues is most likely to create Rayleigh Scattering?
a. red blood cells
b. muscle
c. fat
d. bone
red blood cells
(True or False) with normal incidence the angle is 180 degrees.
false
Under which of the following conditions is axial resolution improved?
a. decreased spatial pulse length
b. decreased pulse amplitude
c. decreased imaging depth
d. decreased pixel size
e. decreased beam diameter
decreased spatial pulse length
Snells law describes physics of ________.
refraction
The most likely amount of reflection at a boundary between soft tissue is:
a. 1%
b. 22%
c. 34%
d. 99%
1%
The most typical amount of transmission at a boundary in biologic media is:
a. 1%
b. 22%
c. 34%
d. 99%
99%
Sound is traveling from medium 1 to medium 2. Propagation speeds of M1 and M2 are 1,600m/s and 1,500m/s, respectively. There is oblique incidence.
a. angle of incidence > angle of reflection
b. angle of incidence = angle of reflection
c. angle of incidence
angle of incidence = angle of reflection
(True or False) Doppler shifts always occur if the sound source and receiver are in motion.
False
Which of 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 reduced sensitivity
e. good temporal resolution and flash artifact
poor temporal resolution and flash artifact
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
difference between incident and reflected frequency
(True or False) The sonographer cannot change, directly or indirectly, the duty factor of an US machine.
false
Depth calibration of a machine measures 100mm spaced wires to be 90mm apart. Scanning reflectors 50mm apart, what will the machine calculate the distance to be?
a. 40mm
b. 45mm
c. 60mm
d. 65mm
45mm
(True or False) There have not been biological effects from US found in the laboratory.
false
In an analog scan converter, what component stores the image data?
dielectric matrix
Which has the correct order?
mega-milli-kilo-micro
a. 10^6 10^-6 10^3 10^-3
b. 10^6 10^-3 10^3 10^-6
10^6 10^-3 10^3 10^-6
How many cm are in 60 millimeters
6
(True or False) Lateral resolution is also called axial.
false
(True or False) Lateral resolution is also called azimuthal
true
(True or False) Lateral resolution is also called longitudinal.
false
(True or False) Lateral resolution is also called range.
false
Which has the correct units? Freq Speed Intensity Attenuation a. Hz mm/s joules dB/cm b. mHz m/sec W/cm^2 dB c. kHz mm/us W/cm^3 dB/cm
mHz m/sec W/cm^2 dB
What increases patient exposure?
a. exam time
b. frequency
c. video taping
d. wavelength
exam time
(True or False) Shadowing may result from high amounts of reflection of US energy.
True
Where are harmonics created?
a. in the receiver
b. in the transducer
c. in the tissues
d. in the beam former
in the tissues
How is range ambiguity artifact eliminated?
a. lower the PRF
b. raise the PRF
c. increase the gain
d. use a lower frequency transducer
lower the PRF
How is lateral resolution measured if this test object is scanned from the top?
a. measure the distance from A to E
b. measure the length of line C and divide by 2
c. measure the length of line B
this is the question with image
measure the length of line B
For Doppler, which incident angle results in no shift?
a. 180
b. 90
c. 0
d. 45
90
Which transducer would be best to image superficial structures?
a. small diameter, high frequency
b. small diameter, low frequency
c. large diameter, high frequency
d. large diameter, low frequency
small diameter,high frequency
A transducer with more than one active element is called?
a. multipurpose
b. annular
c. mechanical
d. array
array
How many bits are needed to represent 16 shades of grey?
a. 2
b. 3
c. 4
d. 5
4
What information does Doppler shift provide?
a. flow
b. cardiac output
c. velocity
d. speed
velocity
(True or False) A sound wave is a pressure wave made of compressions and rarefractions.
true
A hydrophone is used to measure
a. velocity
b. frequency
c. intensity
d. phase
intensity or frequency
Images on videotape are stored using:
a. magic
b. magnetism
c. paper
d. computer memory
magnetism
Circumferences may be measured in unit of:
a. cm
b. cm squared
c. cubic cm
d. cubits
cm
Decimal uses a base of 10, binary uses a base of
a. 1
b. 2
c. 5
d. 10
2
If the frame rate increases and the lines per frame is unchanged, what else must happen?
a. US speed increases
b. frequency increases
c. depth increases
d. depth decreases
depth decreases
Which of these cannot be performed by a sonographer?
a. adjust overall gain
b. clean VCR recording heads
c. clean pixels
d. adjust TGC
clean pixels
Which of the following is not a beam steering technique for a mechanical scanhead?
a. rotating wheel
b. phased beam
c. oscillating disc
d. oscillating mirror
phased beam
(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
(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
(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
(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
How many decibels is related to 90% decrease in imaging power
-10dB
If the output of an US machine is calibrated in dB and the output is increased by 20 dB, the beam intensity is increased
a. 100 times
b. 1,000,000 times
c. 20 times
d. 10 times
100 times
Which has the greatest amount of attenuation?
a. bone
b. fat
c. water
d. muscle
done
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
large pixels with many bits/pixel
What is not the responsibility of the sonographer?
a. clean the filters
b. adjust the recorder
c. adjust converter matrix
d. change paper
adjust the converter matrix
