Film Critique Flashcards
What do we look for when assessing radiographic quality
- degree of black and white
- shades of grey
- correct exposure factors
- correct pt positioning
- correct anatomy seen
- anatomical marker used
- sharpness
What is density
The degree of blackening of the film
is related to the exposure factors and the processing technique
what are Exposure factors?
is a general term referring to exposure factors used (kVp, mAs, FFD)
What does it mean when the image is too dark?
the film is OVER EXPOSED too much mAs or the film is OVER PENETRATED too much kVp
How do we tell if an image it over exposed or over penetrated
- if the cortex of the bone is burnt out, it is OVERPENETRATED (too much kVp)
- If the soft tissues are black but the bone cortex can still be seen, it is OVEREXPOSED (too much mAs)
What does it mean if the image is too light?
if the image is too light, the film is UNDEREXPOSED or UNDERPENETRATED
What does it mean if the background of the radiograph is not black?
The mAs was too low
What does it mean if the bony trabeculae cannot be seen or there are white areas with no density in the ROI
The kVp is too low
how to remedy UNDER DEVELOPMENT
- Top up chemicals with replenisher, not water
- changing the developer regularly
- Use correct developer temperature
- use correct developing time
- Warm up automatic processors fully before using
When does OVER DEVELOPMENT happen
Occurs when the developer is too hot or the film is in for too long
When does UNDER DEVELOPMENT happen
Occurs due to diluted, exhausted or cold developer or developing for too short a time
What does high contrast mean?
White image on a black back ground with a few shades of grey = low latitude
what does low contrast mean?
The film has too many shades of grey
What is sharpness
The clarity of structures visable on a radiograph
What can affect sharpness?
- respiration
- plate movement
- scatter - use grid
- Fog (reduces contrast)
- poor screen contact
