Physics-Sound Beams

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Author:
aprilh4485
ID:
115941
Filename:
Physics-Sound Beams
Updated:
2011-11-10 23:11:07
Tags:
Sonography
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Description:
Sound Beams
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  1. What is the best estimate of the diameter or width of the sound beam as it exits the transducer?
    12 mm
  2. What is the diameter of the sound beam at a depth of 8 cm?
    6 mm
  3. What is the diameter of the sound beam at a depth of 16 cm?
    12 mm
  4. At what depth is the focus?
    8 cm
  5. What depth marks the beginning of the focal zone?
    6 cm
  6. What depth marks the end of the focal zone?
    10 cm
  7. At which of the following depths is the beam narrowing?
    A. 9 cm
    B. 12 cm
    C. 10 cm
    D. 8 cm
    E. 6 cm
    E. 6 cm
    (this multiple choice question has been scrambled)
  8. At which of the following depths is the beam widening?
    A. 2 cm
    B. 8 cm
    C. 4 cm
    D. 9 cm
    E. 6 cm
    D. 9 cm
    (this multiple choice question has been scrambled)
  9. At which of the following depths is the beam most likely to have the same diameter as it has at a depth of 11 cm?
    A. 1 cm
    B. 8 cm
    C. 3 cm
    D. 14 cm
    E. 5 cm
    E. 5 cm
    (this multiple choice question has been scrambled)
  10. A pair of 6 MHz probes are identical except for active element diameter. The active element diameters are 6 mm and 10 mm, respectively. The sound beam of which probe will have a shallower focus?
    the probe with a 6 mm active element has a shallower focus.
  11. A pair of 9 mm diameter probes are identical except for frequency, which is 3 MHz and 6 MHz, respectively. Which beam will have a shallower focus?
    3 MHz
  12. Which of the following probes creates a beam with the deepest focus?
    A. 4 mm diameter, 4 MHz
    B. 6 mm diameter, 8 MHz
    C. 6 mm diameter, 2 MHz
    d. 5 mm diameter, 8 MHz
    • B. 6 mm diameter, 8 MHz
    • it has the biggest diameter and highest frequency, so it creates a beam with the deepest focus
  13. Which of the following probes creates a beam with the shallowest focus?
    A. 4 mm diameter, 4 MHz
    B. 6 mm diameter, 8 MHz
    C. 4 mm diameter, 2 MHz
    D. 5 mm diameter, 8 MHz
    • C. 4 mm diameter, 2 MHz
    • it has smallest diameter and lowest frequency, so it creates a beam with the shallowest focus
  14. True or False.
    Transducer frequency and near zone length are inversely related?
    • false
    • they are directly related
  15. True or False.
    Wavelength and near zone length are inversely related?
    True.
  16. True or False.
    Active element diameter and near zone length are directly related.
    True
  17. A pair of 6 MHz probes are identical except for active element diameter, which is 6 mm and 10 mm, respectively. Which beam will be more compact in the far field?
    the transducer with the 10 mm active element
  18. A pair of 9 mm diameter probes are identical except for frequency, which are 3 MHz and 6 MHz. Which sound beam will spread out more in the far field?
    3 MHz beam is more divergent
  19. Which of the following probes creates a beam with the least divergence?
    A. 4 mm diameter, 4 MHz
    B. 6 mm diameter, 8 MHz
    C. 6 mm diameter, 2 MHz
    D. 5 mm diameter, 8 MHz
    • B. 6 mm diameter, 8 MHz
    • divergence is minimized with large diameter, high frequency probes.
  20. Which of the following probes creates a beam with the most divergence?
    A. 4 mm diameter, 4 MHz
    B. 6 mm diameter, 8 MHz
    C. 4 mm diameter, 2 MHz
    D. 5 mm diameter, 8 MHz
    • C. 4 mm diameter, 2 MHz
    • divergence is pronounced with small diameter, low frequency probes
  21. True or False.
    Transducer frequency and beam divergence are inversely related.
    True
  22. True or False.
    Active element diameter and beam divergence are inversely related.
    True
  23. What is the lateral resolution at a depth of 8 cm?
    4.5 mm
  24. What is the lateral resolution at a depth of 16 cm?
    9 mm
  25. What is the best estimate for the resolution at 4 cm?
    A. 9 mm
    B. 1 cm
    C. 15 mm
    D. 5 mm
    D. 5 mm
    (this multiple choice question has been scrambled)
  26. What is the best estimate for the resolution at 7 cm?
    A. 1 cm
    B. 5 mm
    C. 9 mm
    D. 14 mm
    B. 5 mm
    (this multiple choice question has been scrambled)
  27. What is the best estimate for the resolution at 21 cm?
    A. 14 mm
    B. 9 mm
    C. 1 cm
    D. 5 mm
    A. 14 mm
    (this multiple choice question has been scrambled)
  28. The ability to distinguish two structures lying close together is called __________.
    resolution
  29. The ability to distinguish two structures lying close together front-to-back is called __________.
    LARRD - longitudinal, axial, range, radial, or depth resolution
  30. The ability to distinguish two structures lying close together side by side is called __________.
    LATA - lateral, angular, transverse, or azimuthal resolution
  31. Axial resolution and lateral resolution are both measured with units of _________.
    distance; mm or cm
  32. When the number of cycles in a pulse increases while the frequency remains the same, the numerical value of the range resolution __________. (increases, decreases, remains the same)
    • increases
    • with more cycles in a pulse, the pulse becomes longer and the numerical value of the range resolution increases
  33. When the number of cycles in a pulse increases (more ringing) while the frequency remains the same, the numerical value of the range resolution ___________. (improves, degrades, remains the same)
    • degrades
    • when # of cycles increases, the spatial pulse length increases and the image quality degrades
  34. ___________ frequency transducers have the best range resolution. (high, low)
    high
  35. Name the 4 synonyms for axial resolution
    longitudinal, range, radial, depth
  36. Name the 3 synonyms for lateral resolution.
    angular, transverse, azimuthal
  37. The length of a pulse is 8 mm. What is the minimum distance between two reflectors, positioned one in front of the other, that still produces two echoes on our image?
    A. 8 mm
    B. 4 mm
    C. 16 mm
    D. 2 mm
    E. cannot be determined
    • B. 4 mm
    • one half the pulse length
  38. The frequency of a transducer does not change. If the diameter of the new piezoelectric crystal increases, what happens to the near zone length?
    increases
  39. The frequency of a transducer does not change. If the diameter of the new piezoelectric crystal increases, waht happens to the beam diameter in the far zone?
    decreases
  40. The frequency of a transducer does not change. If the diameter of the new piezoelectric crystal increases, what happens to the wavelength?
    no change.
  41. The frequency of a transducer does not change. If the diameter of the new piezoelectric crystal increases, what happens to the beam diameter in the near zone?
    increases
  42. Which of the following transducers has the best lateral resolution deep in the far zone?
    A. lowest frequency, largest crystal diameter
    B. highest frequency, largest crystal diameter
    C. lowest frequency, smallest crystal diameter
    D. highest frequency, smallest crystal diameter
    • B.
    • narrow beams improve lateral resolution; highest frequency and largest diameter produces the narrowest beam.
  43. Which of the following transducers has the best lateral resolution deep in the far field?
    A. 4 MHz, 4 mm crystal diameter
    B. 6 MHz, 4 mm crystal diameter
    C. 4 MHz, 6 mm crystal diameter
    D. 6 MHz, 6 mm crystal diameter
    • D.
    • highest frequency and largest diameter creates narrowest beam which have best lateral resolution in the far field

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