# Ultrasound Physics

170 Questions

Ultrasound Physics Questions

• 1.
Which is not an acoustic variable?
• A.

Density

• B.

Pressure

• C.

Distance

• D.

Intensity

• 2.
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 contructive and destructive interference at different times

• 3.
Put in decreasing order
• A.

Deca

• B.

Deci

• C.

Micro

• D.

Centi

• 4.
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

• 5.
• A.

10,000 Hz

• B.

1,000 kHz

• C.

1kHz

• D.

1MHz

• 6.
If the frequency of an US wave is doubled, what happens to the period?
• A.

Doubles

• B.

Halved

• C.

Remains the same

• D.

4 times greater

• 7.
The units of pulse repetition frequency are:
• A.

Per minute

• B.

Msec

• C.

Mm/us

• D.

MHx

• 8.
The time from the beginning of a pulse until its end is__________?
• A.

Period

• B.

Pulse duration

• C.

Pulse length

• D.

PRF

• 9.
The time that a transducer is pulsing is measured at 18 seconds in one hour of total elapsed time.  What is the duty factor?
• A.

0.3

• B.

0.005

• C.

0.5Hz

• D.

0.005msec

• 10.
If a wave's amplitude is doubled, what happens to the power?
• A.

Nothing

• B.

Halved

• C.

Dpib;ed

• D.

• 11.
If the level of an acoustic variable ranges from 55 to 105, what is the amplitude?
• A.

105

• B.

50

• C.

25

• D.

55

• 12.
• A.

• B.

Doubled

• C.

Halved

• D.

Unchanged

• 13.
Put these intensities in decreasing order
• A.

SATP

• B.

SPTP

• C.

SATA

• D.

SPTP, SATP, SATA

• E.

SPTP SATA, SATP

• 14.
The duty factor for continuous wave ultrasound is
• A.

10.0

• B.

1%

• C.

1.0

• D.

0.0%

• 15.
What is the minimum value of the SP/SA factor?
• A.

10.0

• B.

1%

• C.

1.0

• D.

0.0%

• 16.
Which pair of intensities has the same value for continuous wave US?
• A.

Spatial peak & spatial average

• B.

Temporal peak & spatial peak

• C.

Pulse average & temporal average

• D.

Spatial average & temporal average

• 17.
The fundamental frequency of a transcucer is 2.5 MHz.  What is the second harmonic frequency?
• A.

1.25 MHz

• B.

4.5 MHz

• C.

4.8 MHz

• D.

5 cm

• 18.
• A.

10 cm

• B.

10 mm

• C.

10 m

• D.

130 mm

• E.

13 cm

• 19.
What is the approximate attenuation coefficient of 1MHz US in soft tissue?
• A.

0.5 dBcm

• B.

1cm

• C.

3dBcm

• D.

1dB

• 20.
• A.

5%

• B.

Two times

• C.

Twenty times

• D.

One hundred times

• E.

One million times

• 21.
The more pixels per inch:
• A.

The better the temporal resolution

• B.

The better is the spatial resolution

• C.

• D.

The higher the reliability

• 22.
If we increase the transducer diameter, the beam diameter in the far zone is:
• A.

Increased

• B.

Decreased

• C.

Unchanges

• 23.
If the transducer diameter increases, the lateral resolution at its smallest dimension is
• A.

Increased

• B.

Decreased

• C.

Unchanged

• 24.
If we increase the frequency the near zone length is
• A.

Increased

• B.

Decreased

• C.

Unchanged

• 25.
If the frequency is decreased, the numerical value of the radial resolution is
• A.

Increased

• B.

Decreased

• C.

Unchanged

• 26.
If the spatial pulse length is 10 mm, what is the axial resolution?
• A.

0.5 cm

• B.

5 cm

• C.

10 mm

• D.

1 cm

• 27.
Which of the following is the best lateral resolution?
• A.

15 mm

• B.

6 mm

• C.

0.06 cm

• D.

2 cm

• 28.
What is the meaning of thermal index = 37
• A.

A tissue temperature may rise 3 degrees Farenheit

• B.

Tissue temperature will rise 3 degrees Celcius

• C.

Tissue temperature may rise 3 degrees Celcius

• D.

Microbubbles 3mm in diameter will burst

• 29.
• A.

Stable cavitation

• B.

Normal cavitation

• C.

Transient cavitation

• D.

Inertial cavitation

• E.

Active cavitation

• 30.
Which of the following has the greatest output intensity
• A.

B-Mode

• B.

Gray scale imaging

• C.

CW Doppler

• D.

Pulsed Doppler

• 31.
Which of the following best decribes the empirical approach to the study of bioeffects?
• A.

Exposure-response

• B.

Cause-effect

• C.

Risk-benefit

• D.

Causation-reaction

• E.

Effect-microstreaming

• 32.
Which of the following best describes the mechanistic approach to the study of bioeffects?
• A.

Cause-effect

• B.

Exposure-response

• C.

Risk-benefit

• D.

Causation-reaction

• E.

Effect-microstreaming

• 33.
The propagation speed of US in the AIUM test object is?
• A.

1m/s

• B.

1.54 m/s

• C.

1.54 mm/us

• D.

1 km/s

• 34.
Enhancement, multipath and side lobes result in:
• A.

Image distortion

• B.

Clearer images

• C.

Artifact

• D.

Resolution problems

• 35.
A mirror image artifact can appear along side of the true anatomy.
• A.

True

• B.

False

• 36.
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

• 37.
The more pixels per inch:
• A.

The better the temporal resolution

• B.

The better the spatial resolution

• C.

• D.

The higher the reliability

• 38.
If we increase the transducer diameter, the beam diameter in the far zone is
• A.

Increased

• B.

Decreased

• C.

Unchanges

• 39.
If the transducer diameter increases, the lateral resolution at its smalles dimension is
• A.

Increased

• B.

Decreased

• C.

Unchanged

• 40.
If we increase the frequency the near zone length is
• A.

Increased

• B.

Decreased

• C.

Unchanges

• 41.
If the frequency is decreased, the numberical value of the radial resolution is
• A.

Increased

• B.

Decreased

• C.

Unchanges

• 42.
If the spatial pulse length is 10mm, what is the axial resolution?
• A.

0.5 cm

• B.

5 cm

• C.

10 mm

• D.

1 cm

• 43.
Which of the following is the best lateral resolution?
• A.

15 mm

• B.

6 mm

• C.

0.06 cm

• D.

2 cm

• 44.
What are the units of longitudinal resolution?
• A.

Hertz

• B.

Rayls

• C.

M/s

• D.

Feet

• 45.
The range equation relates distant from the reflector to __________ and __________.
• A.

Time-of-flight, distance

• B.

Frequency, wavelength

• C.

Time of flight, propagation speed

• D.

Propagation speed, density

• 46.
Doppler shifts always occur if 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

• B.

False

• 47.
What is the most typical Doppler shift measured clinically?
• A.

3.5 MHz

• B.

3,500,000 Hz

• C.

2 kHz

• D.

1,000 kHz

• E.

20,000 Hz

• 48.
Assuming a constant frequency, what happens if the diameter of an unfocused circular transducer is increased?
• A.

The distance to the far field is reduced

• B.

The beam width is the near field is reduced

• C.

The beam width in the near field is increased

• D.

The US wavelength is increased

• E.

The sensitivity is reduced

• 49.
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 the 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

• 50.
Doppler shifts are always created when the source and receiver are in motion relative to each other.
• A.

True

• B.

False

• 51.
Fill in of an anechoic structure such 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

• 52.
According to the AIUM statement on bioeffects, there have been no concirmed bioeffects below intensities of _________ watts per square centimeter SPTA.
• A.

10

• B.

0.01

• C.

0.1

• D.

1

• E.

100

• 53.
What component of the US unit contains the memory bank?
• A.

Transducer

• B.

• C.

Display

• D.

Scan converter

• 54.
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

• 55.
What are typical clinical Doppler frequencies?
• A.

1 - 10, 000 Hz

• B.

1 - 10 MHz

• C.

2 - 1,000 kHz

• D.

40 - 45 kHz

• 56.
If 3 MHz 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.

10dB

• D.

1.5dB

• 57.
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 samce

• D.

2 times

• 58.
The gray scale can be changed by the sonographer
• A.

True

• B.

Fales

• 59.
How many bits are needed to represent 14 shades of gray?
• A.

14

• B.

1

• C.

4

• D.

3

• E.

8

• 60.
The manufacturer increases the number of lines per frame.  As a result, which of the following may have to decreased.  Frequency
• A.

True

• B.

False

• 61.
The manufacturer increases the number of lines per frame.  As a result, which of the following may have to decreased. FRAME RATE (TRUE OR FALSE)
• A.

True

• B.

False

• 62.
The manufacturer increases the number of lines per frame.  As a result, which of the following may have to decreased.  (Sector Angle)
• A.

True

• B.

False

• 63.
The manufacturer increases the number of lines per frame.  As a result, which of the following may have to decreased. (IMAGING DEPTH)
• A.

True

• B.

False

• 64.
The manufacturer increases the number of lines per frame.  As a result, which of the following may have to decreased. Power Output
• A.

True

• B.

False

• 65.
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 in a medium

• 66.
What artifact has a grainy appearance and is caused by the interference effects of scattered sound?
• A.

Spackle

• B.

Reverberation

• C.

Slice tickness

• D.

Speckle

• E.

Section thickness

• 67.
Multiple reflections that are equally spaced are called:
• A.

Refractions

• B.

Reverberations

• C.

• D.

Comets

• 68.
Axial resolution is affected by focusing.
• A.

True

• B.

False

• 69.
Which of the following choces determines the signal amplitude in the transducers of an ultrasound system?
• A.

Reflected intensity of the sound beam

• B.

Post processing

• C.

Edge enhancement filtering

• D.

Persistence

• E.

Demodulation

• 70.
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

• 71.
Refraction only occurs if there is :
• A.

Normal incidence and differenct impedances

• B.

Indirect intensity and differenct propagation speeds

• C.

Oblique incidence and different propagation speeds

• D.

Oblique frequency and identical impedances

• 72.
The most likely amount of reflection at a boundary between soft tissue is:
• A.

1 %

• B.

22 %

• C.

33%

• D.

99%

• 73.
Sound is traveling from medium 1 to medium 2.  Propagation speeds of M1 and M2 are 1600m/s and 1500m/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 reflection

• 74.
Depth calibration of a machine measures 100 mm spaced wires to be 90 mm apart.  Scanning reflectors 50 mm apart, what will the machine calculate the distance to be?
• A.

40 mm

• B.

45 mm

• C.

60 mm

• D.

65 mm

• 75.
In an analog scan converter, what component stores the image data?
• A.

Computer memory

• B.

Video tape recorder

• C.

Dielectric matrix

• D.

None of the above

• 76.
When the US machine displays only strong reflecting objects and nothing else, the sonographer should
• A.

• B.

Increase output power

• C.

Increase lateral resolution

• D.

• 77.
If a reflector is moved twice as far away from the tranducer, how will this affect the time of flight of a sound pulse?
• A.

• B.

Double it

• C.

No change

• D.

Halve it

• 78.
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

• 79.
At what location in a sound beam is the SPTA intensity the highest?
• A.

Focal point

• B.

Focal zone

• C.

Fresnel zone

• D.

Fraunhofer zone

• E.

Half value depth

• 80.
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

• 81.
• A.

36 X 10 ^6

• B.

3,600

• C.

10,000

• D.

9.5 x 10^5

• E.

9 x 10 ^4

• 82.
What can pulsed Doppler measure that continuous wave cannot?
• A.

Duration

• B.

Speed

• C.

Velocity

• D.

Location

• E.

Frequency

• 83.
What is the fraction of time that sound is transmitting?
• A.

Duty factor

• B.

Pulse duration

• C.

Period

• D.

PRF spatial duration

• 84.
If the SPTA of the following were equal, which would have the lowest SPPA?
• A.

Doppler

• B.

Annular array real time

• C.

Static B-scan

• D.

Linear arry

• E.

Continuous wave

• 85.
The dB is defined as the _______________ of two intensities
• A.

Sum

• B.

Difference

• C.

Product

• D.

Ratio

• 86.
• A.

3 dB

• B.

6 dB

• C.

9 dB

• D.

8 dB

• 87.
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 50% of full intensity?
• A.

-3dB

• B.

-50 dB

• C.

10 dB

• D.

3 dB

• E.

-10 dB

• 88.
• A.

- 3dB

• B.

-50 dB

• C.

40 dB

• D.

3 dB

• E.

-10 dB

• 89.
What may be a unit of amplitude?
• A.

Cm

• B.

Hz

• C.

Msec

• D.

Watts

• E.

None of the above

• 90.
A Doppler exam is performed with a 5MHz probe and a PRF of 15kHz.  Which of these Doppler shifts will create aliasing?
• A.

2 kHz

• B.

2.5 kHz

• C.

7.5 kHz

• D.

14 kHz

• 91.
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.

100

• 92.
Which of the following is not a measure of area?
• A.

Square cm

• B.

Meters squared

• C.

Cubic meters

• D.

Feet x feet

• 93.
Which of the following is true of all waves?
• A.

They travel through a medium

• B.

All carry energy from one side to another

• C.

Their amplitudes do not change

• D.

They travel in a straight line

• 94.
Is Intensity an acoustic variable?
• A.

True

• B.

False

• 95.
• A.

Three times larger than the original

• B.

One third of the original

• C.

Six times more than the original

• D.

Unchanged

• 96.
Which of the following units are appropriate to describe the period of an acoustic wave?  More than one answer maybe correct.
• A.

Minutes

• B.

Microseconds

• C.

Meters

• D.

Mm/us

• 97.
Two waves arrive at the same location and interfere.  The resultant sound wave is smaller that either of the two original waves.  What is this called?
• A.

Constructive interference

• B.

Angular interaction

• C.

Destructive interference

• D.

In-phase waves

• 98.
Ultrasound is defined as a sound with a frequency of
• A.

Greater thatn 20,000 kHz

• B.

Less thatn 1 kHz

• C.

Greater than 10 MHz

• D.

Greater thatn 0.02 MHz

• 99.
Compare two sound waves. A and B.  The frequency of a wave A is one-third that of wave B.  How does the period of a wave A compare the period of wave B?
• A.

A is one-third as long a B

• B.

A is the same as wave B

• C.

A is three times as long as B

• D.

Cannot be determined

• 100.
Which of the following wave is ultrasonic and least useful in diagnotic ultrasound?
• A.

2 MHz

• B.

2000 Hz

• C.

24 kHz

• D.

7.5 MHz

• 101.
True of False:  With standard diagnostic imaging instrumentation, the sonographer has the ability to vary the amplitude of a sound wave produced by the transducer.
• A.

Ture

• B.

False

• 102.
The power of an ultrasound wave can be reported with which of the following units? More than one answer maybe correct.
• A.

Watts/square centimeter

• B.

DB/Cm

• C.

Watts

• D.

Kg/cm^2

• 103.
The maximum value of the density of an acoustic wave is 60 lb/in^2 while the minimum density is 20 lb/in^2.  What is the amplitude of the wave?
• A.

20 lb/in^2

• B.

40 lb/in^2

• C.

60 lb/in^2

• D.

None of the above

• 104.
The final amplitude of an acoustic wave is reduced to one-half of its original value.  The final power is _______ the original power.
• A.

The same as

• B.

One-half

• C.

Double

• D.

None of the above

• 105.
The amplitude of an acoustic wave decreases from 27 pascals to 9 pascals.  If the initial power in the wave was 27 watts, what is the wave final power?
• A.

3 watts

• B.

9 watts

• C.

1 watt

• D.

None of the above

• 106.
What are the units of intensity?
• A.

Watts

• B.

Watts/cm

• C.

Watts/cm^2

• D.

DB

• 107.
If the power in an ultrasound beam is unchanged, while at the same time, the beam area doubles, then the beams's intensity
• A.

Doubles

• B.

Is halved

• C.

Is quartered

• D.

Remains the same

• 108.
What happens to an acoustic beams's intensity when the power in the beam increases by 25% while the cross sectional area of the beam remain the same?
• A.

It increased by 25%

• B.

Increases by 75%

• C.

It increases by 50%

• D.

Decreases by 25%

• 109.
When the power in an acoustic beam is doubled and the cross sectional area of the beam is halved, then the intensity of the beam is
• A.

Doubled

• B.

Halved

• C.

Quartered

• D.

Four time larger

• 110.
What determines the intensity of an ultrasound beam after it has traveled through the body?
• A.

The sound wave's source

• B.

The medium throught which the sound travels

• C.

Both A and B

• D.

Neither choice A nor B

• 111.
What happens to the intensity of an ultrasound beam when the beam's cross-sectional area remains unchanged while the amplitude of the wave triples.
• A.

It triples

• B.

Increases ninefold

• C.

Remains the same

• D.

None of the above

• 112.
The wavelength of a cycle in an ultrasound wave can be reported with which units?
• A.

Units of time (seco, min, etc)

• B.

Units of distance (feet, cm)

• C.

Units of area (m^2, etc

• D.

Mm only

• 113.
Which of the following terms best describes the relationship between frequency and wavelength for sound traveling in soft tissue?
• A.

Receiprocal

• B.

Direct

• C.

Related

• D.

Inverse

• 114.
(TRUE OR FALSE) The power in the wave increases as it travels through the mass. (An ultrasound pulse propagates from soft tissue through a mass.  Sound's propagation speed in the mass is 1575 m/s.)
• A.

True

• B.

False

• 115.
The frequency closest to the lower limits of US is:
• A.

19,000kHz

• B.

10,000 MHz

• C.

20,000 msec

• D.

15,000 Hz

• 116.
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

• 117.
_____________ is the distance covered by one cycle
• A.

Pulse length

• B.

Wavelength

• C.

Cycle distance

• D.

Cycle duration

• 118.
If the frequency of US is increased from 0.77 MHz to 1.54 MHz, what happens to the wavelength?
• A.

Doubles

• B.

Halved

• C.

Remains the same

• D.

4 times greater

• 119.
If the frequency is decreased, the numberical value of the radial resolution is
• A.

Increased

• B.

Decreased

• C.

Unchanged

• 120.
If we increase the frequency, the near zone length is
• A.

Increased

• B.

Decreased

• C.

Unchanged

• 121.
The digital scan converter has a number of pixels assigned to each bit.
• A.

True

• B.

False

• 122.
The more bits per pixel
• A.

The better the resolution

• B.

The higher the pizel density

• C.

• D.

Higer reliability

• 123.
What is the actual time that an US machine is creating a pulse?
• A.

Duty factor

• B.

Period

• C.

Pulse period

• D.

Pulse duration

• 124.
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

• 125.
What is the most typical Doppler shift measured clinically?
• A.

3.5 MHz

• B.

3,500,000 Hz

• C.

2kHz

• D.

1,000 kHz

• E.

20,000 Hz

• 126.
If the frequency is decreased, the numerical value of the radial resolution is
• A.

Increased

• B.

Decreased

• C.

Unchanges

• 127.
The digital scan converter has a number of pixels assigned to each bit.
• A.

True

• B.

False

• 128.
The more bits per pixel
• A.

The better the resolution

• B.

The higher the pixel density

• C.

• D.

Higher reliability

• 129.
Increasing the frequency increases the penetration depth.
• A.

True

• B.

False

• 130.
All 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

• 131.
What componet of a transducer changes electrial to mechanical and mechanical back to electrical engery?
• A.

PZT

• B.

Scan converter

• C.

Demodulator

• D.

• 132.
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

• 133.
What measures the output of the a transducer?
• A.

• B.

Display

• C.

Hydrometer

• D.

Hydrophone

• 134.
Which type of artifact appears most commonly with highly reflective objects?
• A.

Reverberations

• B.

Mirroring

• C.

• D.

Enhancement

• E.

Defocusing

• 135.
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

• 136.
• 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

• 137.
Which of the following is not used to measure the output of ultrasound systems?
• A.

Calibrated absorpterometer

• B.

Hydrophone

• C.

Thermocouple

• D.

Calorimeter

• E.

Liquid crystals

• 138.
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

• 139.
Post processing occurs when the image
• A.

Is played off the VCT

• B.

Entered the A/D converter but before display

• C.

After it leaves the A/D converter

• D.

After it leaves the can converter

• 140.
What happens to venous blood flow to the heart during expiration?
• A.

Increases

• B.

Decreases

• C.

Unchanged

• 141.
Which of the following has a propagation speed closest to "soft tissue"?
• A.

Muscle

• B.

Fat

• C.

Bone

• D.

Air

• 142.
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

• 143.
An amplifier of an ultrasound system increases the voltage of a signal from 0.0001 to 0.1 volt.  What is the amplification?
• A.

60 dB

• B.

30 dB

• C.

1,000 dB

• D.

90 dB

• 144.
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

• 145.
With good images on the CRT but not on the strip chart recorder, one should
• A.

Increase the gain

• B.

• C.

Check the scan converter

• D.

• 146.
Shadowing may result from high amounts of reflection of US energy.
• A.

True

• B.

False

• 147.
Where are harmonics created?
• A.

• B.

In the transducer

• C.

In the tissue

• D.

In the beam former

• 148.
How is range ambiguty artifact eliminated?
• A.

Lower the PRF

• B.

Raise the PRF

• C.

Increase the gain

• D.

Use a lower frequency transducer

• 149.
For Doppler, which incident angle reults in no shift?
• A.

180

• B.

90

• C.

0

• D.

45

• 150.
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

• 151.
What information does Doppler shift provide?
• A.

Flow

• B.

Cardiac out put

• C.

Velocity

• D.

Speed

• 152.
Circumferences are usually measured in:
• A.

Cm

• B.

Cm squared

• C.

Cubic cm

• D.

Cubits

• 153.
Decimal uses a base of 10, binary uses a base of
• A.

1

• B.

2

• C.

5

• D.

10

• 154.
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

• 155.
How many decibels is related to 90% decrease in imaging power?
• A.

-1dB

• B.

-10dB

• C.

-90dB

• D.

-100dB

• 156.
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

• 157.
Which has the greatest amount of attenuation?
• A.

Bone

• B.

Fat

• C.

Water

• D.

Muscle

• 158.
Refraction only occurs if there is :
• A.

Normal incidence and different impedances

• B.

Indirect intensity and differenct propagation speeds

• C.

Oblique incidence and different propagation speeds

• D.

Oblique frequency and identical impedances

• 159.
With normal incidence, what factors affect refraction of US?
• A.

Propagation speeds

• B.

Frequencies

• C.

Attenuation coefficients

• D.

None of the above

• 160.
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

• 161.
The sonographer cannot change, directly or indirectly, the duty factor of an US machines.
• A.

True

• B.

False

• 162.
There have not been biological effects from US found in the laboratory.
• A.

True

• B.

False

• 163.
As the impedances of two media become vastly different, the
• A.

Reflection increases

• B.

Transmission increases

• C.

Refraction increases

• D.

Absorption increases

• 164.
What is the minimum value of the duty factor?
• A.

10.0

• B.

1%

• C.

1.0

• D.

0.0%

• 165.
Assuming a fixed frequency, what happens if the diameter of an ultrasound circular transducer is increased?
• A.

The distance to the far field is reduced

• B.

The beamwidth in the near field is reduced

• C.

The beamwidth in the far field is reduced

• D.

The ultrasonic wavelength is increased

• E.

The sensitivity is reduced

• 166.
From a safety standpoint, which one of the following methods is best?
• A.

Low transmitter output and high receiver gain

• B.

High transmitter 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

• 167.
Which one of the following instruments is a component that stores digital echo signal information?
• A.

Demodulator

• B.

• C.

Video monitor

• D.

Logarithmic amplifier

• E.

Scan converter

• 168.
The dynamic range of the receiver of an ultrasound instrument refers to the
• A.

Ability of the receiver to track a rapidly moving structure

• B.

Range of echo signal frequencies that can be processed without distortion

• C.

Speed with which the receiver recovers following the excitation pulse to the transducer

• D.

Depth range in tissue over which moving echoes can be received

• E.

Range of echo signal amplitudes that can be processed without distortion

• 169.
A sound wave leaves its source and travels through air.  The speed of sound in air is 330 m/sec.  One second later, an echo returns to the source.  At what distance from the source is the reflector that produced the echo?
• A.

1540 meters

• B.

770 meters

• C.

660 meters

• D.

330 meters

• E.

165 meters

• 170.
Whichone of the following statements is true about a single pulse of ultrasound from a transducer?
• A.

It contains a range of frequencies

• B.

It contains sound at the nominal frequency of the transducer only

• C.

It contains sound at the center frequency of the transducer only

• D.

The shorter the pulse the narrower the bandwidth

• E.

Sound engery is continuously transmitted

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