Ultrasound Physics

170 Questions
Physics Quizzes & Trivia

Ultrasound Physics Questions

Please wait...
Questions and Answers
  • 1. 
    • 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. 

      Quadrupled

  • 11. 
    • A. 

      105

    • B. 

      50

    • C. 

      25

    • D. 

      55

  • 12. 
    • A. 

      Quadrupled

    • 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. 
    • 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. 

      The more shades of gray

    • 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. 
    • 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. 

      The more shades of gray

    • 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. 

      Receiver

    • 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. 

      Shadows

    • 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. 

      Adjust the gain

    • B. 

      Increase output power

    • C. 

      Increase lateral resolution

    • D. 

      Adjust the TGC

  • 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. 

      Quadruple it

    • 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. 
    • 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. 

      The more shades of gray

    • 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. 

      The more shades of gray

    • 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. 

      Receiver

  • 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. 

      Receiver

    • B. 

      Display

    • C. 

      Hydrometer

    • D. 

      Hydrophone

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

      Reverberations

    • B. 

      Mirroring

    • C. 

      Shadowing

    • 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. 

      Check the scan head

    • C. 

      Check the scan converter

    • D. 

      Adjust the recorder

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

      True

    • B. 

      False

  • 147. 
    Where are harmonics created?
    • A. 

      In the receiver

    • 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. 

      Receiver

    • 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