image quality

• What is the primary control of contrast in radiography?

  kVp
• What is the primary control of density in radiography?

  mAs
• What are the principal factors affecting the radiograph?

  • Radiographic quality
  • Film factors
  • Geometric factors
  • Subject factors
  • Tools for improved radiographic quality
• What does radiographic quality refer to?

  Exactness of anatomical structure representation
• What are the most important characteristics of image quality?

  • Spatial resolution
  • Contrast resolution
  • Noise
  • Artifacts
• What is spatial resolution in radiography?

  Ability to distinguish two separate objects
• What is contrast resolution?

  Ability to distinguish similar contrast structures
• What is noise in radiography?

  Random fluctuation of optical density
• How can noise be reduced in radiography?

  By increasing the mAs
• What does speed refer to in radiographic quality?

  Speed of the image detector registering radiation
• What are the general rules regarding image receptor speed?

  • Fast receptors: high noise, low resolution
  • High resolution: low noise, slow receptors
  • Low noise: slow receptors with high resolution
• What are artifacts in radiography?

  Damage or foreign material on the receptor
• What are the film factors in radiography?

  • Characteristic curve
  • Optical density
  • Film processing
• What is the characteristic curve in radiography?

  Graph of optical density versus radiation exposure
• What does optical density refer to?

  Degree of blackening on the radiograph
• Why is proper film processing important?

  It affects image receptor contrast and fog density
• What are the geometric factors in radiography?

  • Magnification
  • Distortion
  • Focal spot blur
  • Heel effect
• What is magnification in radiography?

  Images larger than the object they represent
• What is shape distortion?

  Unequal magnification of different object portions
• What is focal spot blur?

  Blurred region on the radiograph
• What is the heel effect?

  Reduced x-ray intensity on the anode side
• What are the subject factors in radiography?

  • Subject contrast
  • Motion blur
• What is subject contrast?

  Contrast determined by subject's characteristics
• What is motion blur?

  Blurring from patient or tube movement
• What are the procedures for reducing motion blur?

  • Use shortest exposure time
  • Restrict patient motion
  • Use large SID
  • Use small OID
  • Suspended inspiration/expiration
• What tools can improve radiographic quality?

  • Proper patient preparation
  • Selection of imaging devices
  • Proper radiographic technique
• What is the importance of patient positioning in radiography?

  Ensures anatomical structure is close to IR
• What is the primary control of contrast in radiography?

  kVp
• What is the primary control of density in radiography?

  mAs