Radiology:Image Receptors

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Radiology:Image Receptors
2013-06-05 21:57:14

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  1. What are the 4 ways to convert invisible ionizing radiation into a visible image?RXCN
    • radiography
    • xerorediography
    • computed tomography
    • nuclear scintigraphy
  2. What uses gamma radiation to scan bone and locate metabolic activity/new growth to pinpoint injury?
    nuclear scintigraphy
  3. Formed with light-sensitive film contained in a cassette.
  4. Holds double-emulsion x-ray film between intensifying screens.
  5. Convert x-ray radiation into visible light, thereby creating a latent image on the film.
    intensifying screens
  6. Converted to a visible image via processing
    latent image
  7. Film holder that holds the x-ray film and intensifying screens in close contact.
  8. The cassette is _ tight
  9. front of cassette =
  10. back of cassette=
    lead to prevent backscatter
  11. How many quadrants may a cassette have?
    quad=4 duh
  12. Name the 3 most common cassette sizes
    • 8x10
    • 11x14
    • 14x17
  13. Why there a 3x7 cm section of lead on the cassette?
    keep film from being exposed
  14. Film is ID'd where?
    dark room
  15. Decrease the amount of radiation exposure required to produce a diagnostic radiograph
    intensifying screens
  16. Efficiency of the screen depends on what 3 factors?
    • high level of x-ray absorption
    • high x-ray to light conversion
    • little to no afterglow
  17. What do the intensifying screens have layers of?
    luminescent phosphor crystals that floresce when struck by x-rays
  18. 95% of film exposure
  19. 5% of film exposure
  20. 4 layers of intensifying screens:BRPP
    • base
    • reflective
    • phosphor
    • protective
  21. Attaches phosphor layer to cassette
    base layer
  22. reflects light emmitted by phosphor layer back towards the x-ray film
    reflective layer
  23. Made of calcium tungstate or rare earth crystals.
    Absorbs x-rays
    Emits light
    Stops emmitting light immediately after exposure
    Phosphor layer
  24. calcium tungstate crystal
    emits blue light
  25. rare earth crystal
    • emits green light
    • better than calcium tungstate
  26. Clear coating on outer surface of screenprotects phosphor layerresists marks and abrasionseasy to clean
    protective layer
  27. What can alter exposure
    any foreign material b/t the screen and film
  28. Intensifying screen speed depends on:CPRD
    • crystal size
    • phosphor layer thickness
    • reflective layer efficiency
    • dyes in phosphor layer to decrease blurring
  29. Quantum mottle
    speed artifact due to inc in speed which causes variation in density on flm
  30. thicker phosphor layer=
    more blurry image
  31. Slow screen sped AKA: HUF
    • high definition
    • ultra detail
    • fine grain
  32. Slow screen =
    _ crystals
    _ detail

    _ mAs
    • small
    • high
    • high
  33. Medium screen speed AKA:RMNP
    • regular
    • midspeed
    • normal
    • par speed
  34. Most common screen speed used?
  35. Medium speed+ _ resolution
  36. Fast screen speed=
    _exposure time
    _ detail
    • dec
    • low
    • large
    • less
  37. Fast screens can penetrate _ tissues
  38. X-ray film has a _ base on both sides with a light sensitive emulsion that contains _ _ crystals.
    • polyester
    • silver halide crystals
  39. Processing film does what?
    convert the split silver halide crystals to a visable image
  40. What are the 4 layers of the x-ray film? BAEP
    • base
    • adhesive
    • emulsion
    • protective
    • covering
  41. Silver crystals are sensitive to flourescent light emitted by the intensifying screens, but less sensitive to _. This helps them require less radiation.
    ionizing radiation
  42. Exposure range over wchich acceptable densities are produced.
    film latitude
  43. Forgiving film. Accepts variations in exposure factors or processing without a major change to density.
    wide latitude
  44. High contrast film. Requires less change in exposure factors or processing to affect density.
    Narrow latitude
  45. Large crystals
    Granier image that lacks definition
    fast film speed
  46. Most widely used in vet med
    Compromise between gran and speed
    medium film speed
  47. Small crystals
    Less grainy image
    Greater definition
    slow film speed
  48. Combined speed of screen and film determines the _ needed.
  49. What differs with manufactuers?
    film number
  50. Medium speed #
  51. As the speed of the system increases the _ decreases
  52. Non-screen film sensitive to _
    direct x-rays
  53. Non-screen films need greater exposure factors because there is no _ of beam from light.
  54. What is non-screen film packaged in?
    light tight heavy envelopes
  55. Example of non-creen film?
  56. 2 dental film speeds. Which is faster?(*)
    • D
    • E*
  57. Film Care:VCL
    • ventrically
    • cool place(50-90F)
    • low humidity (40-60%)
  58. How often are screens cleaned?
  59. What is used to clean screens?
    • commerical cleaner
    • 70% alcohol