Conventional Radiography

  • Created by: EllisA
  • Created on: 05-04-18 15:18
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  • Conventional Radiography
    • What is Conventional Radiography?
      • Obtains a 3D image via xrays
      • as beam is generated and passed through a patient or detector, producing an image
      • different soft tissues attenuate x-ray photons differently on tissue density
        • dense- white
        • gas/air- black
    • TERMS
      • Sensitivity: the proportion of people with disease who have a positive test result
      • Exposure: Kvp and mAs   influence and determine the quantity of rad. to which the patient is exposed to.
        • overexposure or underexposure result in loss of contrast therefore, loss of diagnostic info
        • controlled by rad: -kilovolt peak -miliamp seconds
      • Kilovolt Peak (kVp): the peak voltage applied to the xray tube determining the highest energy of the xray photon
        • responsible for acceleration between cathode and anode
        • controls quality of beam and contrast
        • if kVp increases more scatter is produced
      • Miliamp (mA): used to measure electrical current and is equal to one thousanth of an ampere
        • mA dettermines no of xrays produced
        • patient dose directly proportional to mA
      • Exposure Time: kept as sort as possible to minimise motion blur from patient movement, expressed in MS
      • Miliamp Seconds: controls density
        • milliamp x time = controls wuality or no of photons produced
    • Process:       1) beam produced 2)passes through patient is modified       3) variations in energy captured by imaging device   4)data converted into visable image for storage and display
      • Via:
        • Computed Radiography
          • sensors are used instead of film
          • more time effiicient and ability to digitally enhance images
        • Digital Radiography
          • IP stores x-ray energy in proportion to the intensity it recieves
          • uses a cassette holding an image plat like an intensifying screen
  • DR is faster than CR with lower dose
    • Computed Radiography
      • sensors are used instead of film
      • more time effiicient and ability to digitally enhance images
  • Distance: exposure of image receptor according to ISL.
    • Distance afects intensity of the xray beam
    • TERMS
      • Sensitivity: the proportion of people with disease who have a positive test result
      • Exposure: Kvp and mAs   influence and determine the quantity of rad. to which the patient is exposed to.
        • overexposure or underexposure result in loss of contrast therefore, loss of diagnostic info
        • controlled by rad: -kilovolt peak -miliamp seconds
      • Kilovolt Peak (kVp): the peak voltage applied to the xray tube determining the highest energy of the xray photon
        • responsible for acceleration between cathode and anode
        • controls quality of beam and contrast
        • if kVp increases more scatter is produced
      • Miliamp (mA): used to measure electrical current and is equal to one thousanth of an ampere
        • mA dettermines no of xrays produced
        • patient dose directly proportional to mA
      • Exposure Time: kept as sort as possible to minimise motion blur from patient movement, expressed in MS
      • Miliamp Seconds: controls density
        • milliamp x time = controls wuality or no of photons produced
  • OVER EXPOSURE:
    • not diagnostic
    • black holes appear
  • black holes appear

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