Image Artifacts Flashcards
Any undesirable OD on an image that does not properly show the anatomy being examined
Image artifacts
What do look at when determining the causes?
patient, processing, exposure, handling & storage
Benefits of early detection
- Lowered operating costs
- Minimize patient exposure to radiation
What do you check before and after PM?
Cleaning of the racks and inspection of components and assemblies
Processor artifacts
Emulsion pickoff, chemical fog, guide-shoe marks, guide shoe and roller scratches, wet pressure sensitization (water marks), chemical spots (dichroic stain/hyporetention)
Occur at 3.1416 inch intervals, because of dirt or a chemical stain on roller
Pi Lines
Pi lines are caused because
the rollers are 1 inch in diameter, 3.1416 represents one revolution of a roller, and artifact appears perpendicular to the film’s direction of travel
Causes emulision pick- off and gelatin buildup resulting sludge deposits on the film
dirty rollers
seen at leading or trailing edge of film caused by improper positioning
Guide shoe marks
Over development of film resulting in excessive values on sensitometry films and OD on radiographic films
Chemical fog
Chemical fog caused by
developer temp, time, and pH too high
Wet- pressure sensitization AKA
Entrance roller marks
Entrance rollers become wet before film is introduced, combination of pressure & water marks forms a series of dark stripes that match the grooves on rollers
Wet- pressure sensitization
Where are wet pressure sensitzation produced?
developer tank
For Wet- pressure sensitization irregular or dirty rollers produces:
small circular patterns of increased OD
Dichroic stain AKA
Curtain effect
2 colors of Dichroic stains and what caused them
Brownish color- caused by oxidized developer
Greenish-yellow caused by incomplete fixation
caused by incomplete washing
hyporetention
plus-density
darker than the background
Minus-density
lighter than the background
Plus density caused by application of physical pressure on the film :
after it was was exposed
Minus density caused by application of physical pressure on the film
before it was was exposed
Plus density caused by:
- poor film handling
- poor loading techniques
- dropping or bending of film before feeding it into the processing
Plus density caused during the
developer stage
Minus density caused by:
- poor film handling
- poor loading techniques
- by dirt or dust in the cassette
Minus density occurs before:
the fixing or washing stage
Exposure artifacts
Motion, heat blur, double exposure, improper patient position, poor film to screen contact, grid lines, grid cutoff, moire effect (zerbra pattern)
Moire effect
double set of grid lines, more in MRI
handling and storage artifacts
Light fog, radiation fog, static, kink marks, scratches, dirty cassettes
Safelight/ radiation fog caused by
- Temperature or humidity too high
- filter bin not properly shielded from radiation
- Safelight too bright
- film left in room during addtional exposures
-Streaks of increased OD
- the darkroom or cassette has white-light leaks
- Light of any improper color that strikes the film before development fogs the film
- lowers image contrast
Kink marks
- Improper handling of film
- Stacking film too high (not positioned on end)
what are the 3 kinds of static artifacts?
crown, tree, smudge marks
Static caused by
temperature or humidity too low
