Image Acquisition

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Image Acquisition
2013-07-20 17:36:25
Image Acquisition

Image Acquisition
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  1. filtration affects:
    • density/brightness
    • contrast
  2. SID affects:
    • density/brightness
    • distortion
    • recorded detail/spatial resolution
  3. focal spot size:
    recorded detail/spatial resolution
  4. grids affect:
    • density/brightness
    • contrast
  5. OID affect:
    • recorded detail/spatial resolution
    • contrast
    • distortion
  6. angle of tube/part/receptor affects:
    • recorded detail/spatial resolution
    • distortion
  7. kVp affect:
    • density/brightness
    • contrast
  8. beam restriction (collimation):
    • contrast
    • density/brightness
  9. 40in (100cm)
    X 1.18
  10. 36in SID, 12 mAs, 12:1 grid
  11. 0.25mm, 1.6mm by 0.10mm
  12. 32 mAs 100 cm
    72 mAs
  13. 10 mAs at 72" SID
    80 kVp, 250mA, 0.240 sec
  14. 110kVp, 4mAs
    110kVp, 4mAs
  15. 100mA, 0.020 sec, 80kV, 200-speed screen
    100mA, 0.020 sec, 80kV, 200-speed screen
  16. 500mA, 0.03 sec, 70kV, 8:1 grid
    500mA, 0.03 sec, 70kV, 8:1 grid
  17. 100 lead strips per inch 0.30mm thick 4mm high
  18. 400mA, 70ms, & 78kV
  19. 75kVp & 25mAs
    75kVp & 25mAs
  20. 200mA, 60ms, 36-in SID
  21. 80" SID, 30" OID
    80" SID, 30" OID
  22. 200mA, 0.25 sec, 65kVp
    200mA, 0.25 sec, 65kVp
  23. 72mAs
  24. blurring caused by motion
    motion unsharpness
  25. grid cutoff due to off-centering would result in:
    overall loss of density
  26. intensifying screens effects
    decrease patient exposure
  27. advantage air gap technique
    eliminates need for grid
  28. 15% rule
    reduced by half
  29. interspaces of a grid
  30. off center grid cut off
    one side of image would be underexposed
  31. low ratio grid, high ratio grid
    absorb more scatter radiation
  32. relationship between SID and density
    inverse square law
  33. PA chest
    • 1 & 2 only
    • excessive density
    • insufficient kilovoltage
  34. grid cut off means
    primary x-ray are absorbed
  35. contrast can measure from a characteristic curve by finding tangent
    straight line portion
  36. which of the following has a direct impact on size distortion on radiography
  37. image on radiographic film after exposure but before development is known as
    a latent image
  38. a larger matrix
    • for same FOV
    • spatial resolution
  39. which of the following has no impact on radiation exposure to patient
    focal spot size
  40. object is place halfway
  41. brightness & contrast resolution in digital imaging can be influenced by
    • (WL)
    • (WW)
    • (LUT)
  42. exposure without screens divided by exposure with screen
    intensification factor
  43. possesses widest dynamic range
  44. image contrast is a result of
    • differential tissue absorption
    • atomic number of tissue being traversed
  45. has no impact on radiation exposure to patient
    focal spot size
  46. modern rare earth intensifying screen are used  primarily to
    reduce patient dose
  47. lateral lumbar asthenic patient
    insufficient radiographic density
  48. recorded detail can be improved by decreasing
    • OID
    • patient/part motion
  49. grid employed
    • large or dense body part
    • when using high kilovoltage
  50. low contrast
    possesses wide latitude before the LUT
  51. primary controlling factor of density is
  52. digital imaging, size of image matrix increase
    • pixel size decrease
    • spatial resolution increases
  53. table bucky device
    grid frequency is too low
  54. 15% rule, kVp increase by 15%
    reduced by half
  55. as beam restriction increases (becomes tighter):
    density decreases
  56. anatomic structures are on top of each other
  57. what is the cause of "pi line" artifact on radigraph
    dirt on the processor transport roller
  58. CR & DR include
    CR uses IPs
  59. off distance grid cut-off is characterized by
    both sides of image are underexposed
  60. AP T-spine
    AP T-spine
  61. what are the effects of scattered radiation on a radiographic image:
    it produces fog
  62. help compensate for varying densities of anatomic structures
    trough filter
  63. line-focus principle expresses the relation between
    actual and the effective focal spot
  64. storage x-ray film
    cool, dry room
  65. histogram is used automatically rescale the image to the proper brightness
    • gross overexposure
    • unexpected metal in the data set
    • exposure field detection
  66. mAs directly controls
    the quantity of x-ray produced
  67. an increase in kV will serve to
    produce a longer scale of contrast
  68. how well an imaging system reproduces the sharpness of actual object is referred to as what
    modulation transfer function
  69. which of the following contrast media, when added body, decreases the tissue density of the body part
    carbon dioxide
  70. which of the following main determinant in selecting a focal spot size
    mA used
  71. S-number of 50/S-number of 200
    mAs should be decreased
  72. essential assurance program is called a:
  73. which of the following is NOT considered one of the geometric factors that control recorded detail/spatial resolution
    size of object
  74. emulsion scratches that run the length of film in the direction of the film travel are usually caused by
    guide shoes out of adjustment
  75. when mA is increases
    decrease time
  76. which of the following defines radiographic density
    overall blackness of the radiograph
  77. which of the following is (are) associated with the subject contrast
    • patient thickness
    • tissue density
    • kilovoltage
  78. film screen system effect on recorded detail is controlled by
    size and layer thickness of screen's phosphors and film's silver halide crystals
  79. to effectively take advantage of anode heel effect, where should the thicker part of anatomy be placed
    over cathode
  80. factors that determine the production of scatter radiation include:
    • kilovoltage
    • beam restriction
    • field size
  81. distortion may be described as:
    • misrepresentation of size or shape of structure
    • elongation
    • foreshortening
  82. recorded detail is:
    geometric representation of the part being radiographed
  83. portion of contrast that is caused by variations in anatomy or is secondary to pathologic changes is called
    subject contrast
  84. absorption of useful radiation by a grid is called
    grid cutoff
  85. which of the following statements about histograms is/are true
    • there is a default histogram for each/different body part
    • a histogram illustrates pixel value distribution
    • a histogram is representative of the image grayscale
  86. during CR imaging, the latent image present on the PSP is changed to a computerized image by
  87. factors that can affect histogram appearance include
    • centering errors
    • incorrect SID
    • beam restriction
  88. purpose of electroconductive layer of a CR PSP plate is to
    facilitate transportation through the scanner/reader
  89. decrease in mAs by 30%
    decrease in mAs by 30%
  90. which of the following will reduce magnification
    use of a short OID
  91. examples of healthcare informatics include
    • HIS
    • RIS
    • PACS
  92. number of grid lines per inch or centimeter defines:
    grid frequency
  93. what type of distortion results from increase in OID
  94. a grid usually is employed in which of the following circumstances
    • when radiographing a large or dense body part
    • when using high kV
  95. insufficient radiographic density
    insufficient radiographic density
  96. which of the following does mAs affect
  97. what is the main purpose of using line focus principle in an x-ray tube
    to decrease the effective focal spot size
  98. which of the following would tell the radiographer what new mAs to use when the SID changes to maintain film density
    direct square law
  99. main differences between direct capture and indirect capture DR is that
    direct capture/conversion has no scintillator
  100. difference in densities on radiograph describes:
  101. how much must the mAs be increased before a noticeable change in density can be seen
  102. device used to test resolution of film screen imaging is a
    line pair test tool
  103. which of the following describes the relationship between SID and density
    inverse square law
  104. because of anode heel effect, intensity of x-ray beam is greatest along the
    cathode end of the beam
  105. 50% less
    50% less
  106. reduce kVp by 15%
    reduce kVp by 15%
  107. with a reduction in field size and all other technical factors remaining unchanged, the radiographic scale of contrast will
  108. what is the primary factor that controls quantity of x-ray photons being created at the target
  109. which of the following is a result of anode heel effect
    radiation intensity is increased on cathode side of tube
  110. what effect does excessive developer temp, have on a finished radiograph
    decreased contrast and increased density
  111. what is a major benefit of a fixed kVp technique chart
    consistent radiographic contrast
  112. in digital imaging, as size of image matrix increases
    • 2 & 3 only
    • pixel size decreased
    • spatial resolution increased
  113. for the same FOV, the matrix size increases
    • image quality increases
    • spatial resolution increases
    • pixel size decreases
  114. no practical amount of mAs can ever compensate for
    inadequate kVp
  115. when using a fixed kVp technical factors should be adjusted for variations in part thickness
  116. demonstrating a long scale of contrast
  117. what does the CR reader use to release the energy stored in the image plate
    red laser light