IMAGE ARTIFACTS

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IMAGE ARTIFACTS
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What is an ARTIFACT

• Any irregularity on an image that is not
  caused by the proper shadowing of tissue by the
  primary beam.
• an undesirable optical density on radiograph

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How are they produced?

• Exposure
• Processing
• Handling Storage

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ARTIFACT FROM EXPOSURE

• Associated with conducting Exam
• Equipment
• Incorrect film screen match or poor
  contact
• Warped or dirty cassettes
• Grid misalignment
• Patient
• preparation or instruction (motion)
• positioning errors
• technical errors

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ARTIFACTS FROM PROCESSING

• Pressure marks from transport of film
• produced during processing and will usually
  appear with a higher OD
• Roller Marks
• Dirty Rollers
• Chemical Fog
• Wet-Pressure Sensitization

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ROLLER MARK

• Guide Shoes-mark on leading or trailing edge of
  film, found parallel to the film travel
  direction. Caused by improper positioned guide
  shoes or spring shoes
• pi lines- 3.1416 inch intervals
• dirt and chemical stains

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DIRTY ROLLERS

• Emulsion Pickoff
• Gelatin buildup-
• sludge
• Can appear as sharp positive or negative optical
  density on film

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CHEMICAL FOG

• Improper or Inadequate processing chemistry
• Chemical Fog- uniform dull grey
• Dichoic Stain- 2 colors
• yellow, green, blue, purple
• Curtain Effect-chemistry running up trailing edge
  or down leading edge

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WET PRESSURE SENSITIZATION

• Developer tank
• Irregular or dirty rollers
• Small circular increased optical density

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HYPO RETENTION

• Hypo - fixing agent
• ammonium thiosulfate
• Improper washing
• Yellowish discoloration to stored
• radiograph

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HANDLING STORAGE

• Radiation and Light fog
• Rough Handling- kink marks
• Static
• Hypo retention
• Kinks
• Scratches

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ARTIFACTS FROM RADIATION AND LIGHT FOG

• Light leaks
• Safelight
• Radiation
• Heat/humidity
• below 68 degrees
• 40 to 60 humidity

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HANDLING

• Before or After processing
• Kink marks
• Scratches
• Fingerprints
• Darkroom environment
• clean dry surfaces

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STATIC

• Electron buildup on emulsion
• Low humidity
• Crown
• Tree
• Smudge

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CASSETTE BASED FILMLESS ARTIFACTSDigital
Radiography and PACS pg 90-98

• IMAGING PLATE ARTIFACTS
• CRACKS AREAS OF LUCENCY
• Adhesive tape residue
• Static causing hair to adhere to plate
• Backscatter

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CASSETTE BASED FILMLESS ARTIFACTSDigital
Radiography and PACS

• PLATE READER ARTIFACTS
• Extraneous line patterns caused by electronics
• White lines (horizontal) dirt on light guide of
  reader
• Loading of more than one IP into a cassetedouble
  exposure artifact
• Grid orientation so that grid lines are parallel
  to the plate readers laser scan moire pattern.
  (Grids should be high frequency and grid lines
  need to run perpendicular to the laser scan line

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CASSETTE BASED FILMLESS ARTIFACTSDigital
Radiography and PACS

• Printer Artifacts
• Fine white lines from debris on mirror in printer
  
• Operator ARTIFACTS
• Insufficient collimation incorrect exposure
  range (S) reading
• Backward cassette
• Underexposure quantum mottle

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DR Processing Artifacts

• Electronic rather than chemical
• Artifacts caused by interference with electronic
  components

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CR Handling and Storage Artifacts

• Debris on image receptor
• Discoloration of fluorescent screens
• Fogging
• ghost images
• dead detector images

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Cassetteless ArtifactsDigital Radiography and
PACS pg 108

• Conversion from x-ray to digital is very fast
• Potential for signal loss
• Electronic noise most typical of artifact
• Rapid exposures can cause lose of
  signalreduction of image quality