Physics-Pulsed Echo Instrumentation/Displays and Image Storage

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Author:
aprilh4485
ID:
116862
Filename:
Physics-Pulsed Echo Instrumentation/Displays and Image Storage
Updated:
2011-11-15 21:46:54
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Sonography
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Pulsed Echo Instrumentation/Displays and Image Storage
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  1. You are using a 4 MHz transducer and have adjusted the time gain compensation (TGC) perfectly, as represented by the red TGC line, You are given a new transducer with an unknown frequenncy. The TGC is then adjusted to create the same image as that obtained by using the 4 MHz transducer--this new TGC setting is the purple dotted line. Is the frequency of the new transducer greater or less than 4 MHz? Why?
    less than 4 MHz because the delay is deeper with the new transducer and at any point in the slope, less compensation is applied with the new transducer
  2. You are using a 4 MHz transducer and have adjusted the time gain compensation (TGC) perfectly, as represented by the red TGC line, You are given a new transducer with an unknown frequenncy. The TGC is then adjusted to create the same image as that obtained by using the 4 MHz transducer--this new TGC setting is the green dotted line. Is the frequency of the new transducer greater or less than 4 MHz? Why?
    higher than 4 MHz, because the TGC curve is shifted upward and toward the right. the delay is shallower.
  3. Which of the following choices is best when the image on your ultrasound system displays reflectors only in a region far from the transducer but no reflectors in a region close to the transducer?
    A. adjust the system's compensation
    B. decrease the output power
    C. adjust the reject level
    D. use a higher frequency transducer
    A. adjust the system's compensation
    (this multiple choice question has been scrambled)
  4. Which of the following choices is best when the image on your ultrasound system is saturated (too bright everywhere)?
    A. decrease the amplification or gain
    B. use a higher frequency transducer
    C. decrease the output power
    D. adjust the reject level
    C. decrease the output power
    (this multiple choice question has been scrambled)
  5. Which of the following choices is best when the image of your ultrasound system displays only bright reflectors but no weak reflectors throughout the image?
    A. adjust the reject leve
    B. increase the output power
    C. increase the system's overall gain
    D. use a higher frequency transducer
    A. adjust the reject level
    (this multiple choice question has been scrambled)
  6. Which of the following choices is best when the image on your ultrasound system displays only reflectors in a region close to the transducer but no reflectors that are deep?
    A. adjust the system's compensation
    B. use a higher frequency transducer
    C. increase the output power
    D. adjust the reject level
    A. adjust the systems compensation
    (this multiple choice question has been scrambled)
  7. All of the following are components of an ultrasound system except:
    A. transducer
    B. pulser
    C. alternator
    D. synchronizer
    E. display
    F. receiver
    C. alternator
  8. This type of pulser generates a constant electrical signal in the form of a sine wave:
    A. pulsed wave, single crystal
    B. pulsed wave, array
    C. continuous wave
    C. continuous wave
    (this multiple choice question has been scrambled)
  9. This type of pulser generates a single electrical spike, which ultimately creates a single sound pulse:
    A. pulsed wave, phased array
    B. pulsed wave, single crystal
    C. continuous wave
    B. pulsed wave, single crystal
    (this multiple choice question has been scrambled)
  10. This type of pulser generates numerous electrical spikes, which ultimately create a single sound pulse:
    A. continuous wave
    B. pulsed wave, single crystal
    C. pulsed wave, phased array
    C. pulsed wave, phased array
    (this multiple choice question has been scrambled)
  11. The acoustic power of a sound beam emitted from a transducer is determined by the ___________ of the pulser's signal.
    A. voltage
    B. PRF
    C. frequency
    D. rectification
    A. voltage
    (this multiple choice question has been scrambled)
  12. All of the following are functions of the receiver except:
    A. attenuation

    B. amplification
    C. demodulation
    D. suppression
    A. attenuation
    (this multiple choice question has been scrambled)
  13. Place these functions in the order in which the ultrasound system performs them:
    A. reject
    B. demodulation
    C. amplificaiton
    D. compression
    E. compensation
    C, E, D, B, A
  14. True or False.
    Amplification processes all reflected signals in a similar manner.
    True
  15. True or False.
    Compensation processes all reflected signals in a similar manner.
    False
  16. What is the number of shades that can be represented by 3 bits?
    • 8
    • 2 X 2 X 2 = 8
  17. What is the number of shages that can be represented by 8 bits?
    • 256
    • 2x2x2x2x2x2x2x2= 256
  18. How many bits are needed to store:
    10 shades of gray?
    11 shades of gray?
    15 shades of gray?
    4 bits are required to store from 9 to 16 shades of gray
  19. All of the following are true of ordinary cathode ray tubes except:
    A. it contains large vacuum tubes with a phosphor-coated screen
    B. Electrons are emitted by a gun and swept across the screen by varying magnetic fields
    C. There are 600 horizontal scan lines from top to bottom, painted in order from 1 to 600
    D. There are 60 fields generated each second that combine into 30 frames per second
    • C.
    • a normal CRT creates images by using 525 horizontal scan lines
  20. Which of the following correctly describes a typical television display?
    A. interlaced
    B. bistable
    C. non-interlaced
    D. progressive scan
    A. interlaced
    (this multiple choice question has been scrambled)
  21. Which electronic component is required for grayscale imaging?
    A. non-interlaced display
    B. scan converter
    C. VCR
    D. computer memory
    B.
    (this multiple choice question has been scrambled)
  22. All of the following are disadvantages of analog scan converters except:
    A. image fade
    B. low-resolution image
    C. image flicker
    D. deterioration
    B.
  23. Which of the following scan converters will provide the best spatial resolution?
    A. digital with 128 x 128 pixels
    B. analog with 1000 x 1000 array
    C. digital with 256 x 256 pixels
    D. digital with 512 x 512 pixels
    B.
    (this multiple choice question has been scrambled)
  24. Which of the following statements regarding a bit of computer memory is false?
    A. it is a component of a digital scan converter
    B. it is the smallest element of an image
    C. it is bistable
    D. eight bits combine to make a byte
    B.
    (this multiple choice question has been scrambled)
  25. How many gray shades can be represented by a group of:
    4 bits?
    2 bits?
    • 4 bits represents 16 shades
    • 2 bits represents 4 shades
  26. Which of the following statements regarding a pixel is false?
    A. it displays up to 3 shades simultaneously
    B. image quality is improves when the number of pixels is high
    C. smallest part of a digitized image
    D. a collection of bits, assigned to each pixel, stores a shade of gray
    A.
    (this multiple choice question has been scrambled)
  27. Are the following prodecures usually pre- or postprocessing?
    A. modifying a frozen image
    B. read zoom
    C. write zoom
    D. adjusting the brightness on the CRT
    E. increasing the receiver gain
    • A. post
    • B. post
    • C. pre
    • D. post
    • E. pre
  28. Are the following forms of information usually digital or analog?
    A. the signal from teh transducer to the receiver
    B. the input signal to the digital-to-analog converter
    C. the output signal from the analog-to-digital converter
    D. the input signal to the analog-to-digital converter
    E. the output signal from the digital-to-analog converter
    F. a typical video signal
    • A. analog
    • B. digital
    • C. digital
    • D. analog
    • E. analog
    • F. analog
  29. All of the following are characteristis of write magnification except:
    A. preprocessing function
    B. more pixels in the region of interest
    C. identical regions stored in the scan converter before and after zooming
    D. it is the preferred method of image magnification
    C.
  30. What is the primary disadvantage of video tape and computer disc methods of image archiving?
    A. only black and white images are stored
    B. the information is vunerable to erasure when exposed to strong magnetic fields
    C. only low resolution images are stored
    D. these methods are very costly
    B.
    (this multiple choice question has been scrambled)
  31. All of the following are advantages of PACS systems except:
    A. data will not deteroriate over time
    B. images can be delivered to distant locations on the imaging network
    C. older, archieved studies and reports can be reviewed easily
    D. images have higher resolution than what appears on the systems display
    D.

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