US Physics 151-180

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amadaperedo
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224424
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US Physics 151-180
Updated:
2013-06-19 23:28:37
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Physics
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Physics
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  1. You are using a 5 MHz, 40 mm linear array transducer to image a structure. What is the width of the image?
    40 mm
  2. You have selected a wide-bandwidth transducer with multiple transmit frequencies to perform a sonographic examination. Which transmit frequency should you select for maximum penetration?
    3.0 MHz (lowest frequency)
  3. Which probe would provide the best axial resolution to measure the thickness of a small structure?
    10 MHz linear array (Axial resolution improves with increasing frequency)
  4. You are performing a sonographic exam with a wide-bandwidth transducer. The advantage you obtain with this transducer compared to narrow-band transducer is:
    Improved axial resolution
  5. Which transducer would provide the longest near-zone length?
    10 MHz, 6 mm diameter aperture (largest diameter transducer)
  6. The location where the sound beam reaches its narrowest diameter is known as the:
    Focal zone
  7. Which of the following transducers creates a rectangular image shape?
    Linear array
  8. The term for a transducer that has an array of rectangular elements arranged in a straight line is:
    Linear array
  9. For a linear array transducer consisting of a single row of elements, what method is most used to focus the beam in the elevational direction?
    Mechanical focusing
  10. What type of transducer could you choose to produce a beam that is symmetrical about the beam axis?
    Annular array
  11. The ultrasound system in your lab has a transducer with a small footprint. This kind of transducer has the following disadvantage:
    Resolution is degraded at large distances
  12. Which of the following will NOT improve axial resolution?
    Increased focusing
  13. You are reviewing an ultrasound image that has a sector display format that narrows to a point at the transducer surface. What kind of transducer was most likely used to acquire this image?
    Phased array
  14. Where is the point of maximum intensity in a sound beam?
    Focal point
  15. What is the main advantage of using a 1 ½D or multirow array transducer?
    Narrow slice thickness over large part of the scanned volume
  16. What benefit would you obtain by choosing a transducer having a large diameter compared to one having a small diameter?
    It can focus at greater depths
  17. You are using a linear array transducer with 4 transmit focal zones. How many pulses are required on each scan line to create the image?
    Four
  18. What type of transducer has the same measurement for elevational and lateral resolution?
    Annular array
  19. With a 1D linear array, where is the dimension of the sound beam in the out-of-plane dimension the narrowest?
    It is at the point of mechanical focusing
  20. Another name for axial resolution is:
    Range resolution
  21. Dynamic apodization is a method employed to:
    Reduce side lobes
  22. Which statement is most accurate regarding resolution with a standard one-dimensional linear array transducer?
    Elevational resolution is the worst measure of resolution with this type of transducer
  23. During the course of a sonographic exam, you notice lateral splaying of the echoes in the far field. What can you do to improve the image?
    Increase the number of transmit focal zones and optimize their location
  24. You suspect that a bright spot on the B-mode image is calcification, but a posterior acoustic shadow is not present. How can you best optimize your system to demonstrate a shadow distal to the calcification?
    Increase the transducer frequency
  25. When an electrical signal is applied to a piezoelectric element, what happens to the element?
    It expands and contracts
  26. You are scanning a phantom containing multiple rows of identical 5 mm spherical fluid structures embedded in a tissue-mimicking material. What type of resolution is best evaluated with this phantom?
    Elevational
  27. Which statement is NOT true regarding lateral resolution?
    It remains constant throughout scanning depth
  28. Which type of transducer should you select to produce the narrowest slice thickness throughout the image plane?
    A 1.5D multi-row array
  29. The matching layer between the piezoelectric element and the tissue is designed to:
    Reduce the acoustic impedance mismatch between the element and tissue
  30. If you choose a lower-frequency transducer to image a highly attenuating structure, what tradeoff are you making?
    Decreased spartial resolution for improved penetration

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