1. Radiographic critique & problem solving
Lecturer: Vicki Denby B.App.Sc (MIT)
Radiographic critique & problem solving

2. WE WILL LOOK AT… Radiograph & film critiquing
Problem solving for radiographic images
Problem solving for processing & technical errors

3. ASSESSING RADIOGRAPHIC QUALITY
When we look at the final radiographic image, we automatically assess the degree of blackness & white, the shades of grey representing various anatomical structures i.e. correct exposure factors used for the ROI (kVp & mAs), correct patient positioning, correct anatomy seen, anatomical marker present & correct, identification present & correct, image sharpness

4. ASSESSING RADIOGRAPHIC QUALITY
DENSITY Density is the degree of blackening of the film It is related to the exposure factors used (kVp & mAs) It is also related to the processing technique

5. EXPOSURE FACTORS
A general term referring to the exposure factors used i.e. kVp, mAs, FFD, focal spot, grid etc
The following 2 slides are an excellent summary of differentiating between a light or a dark film & the correct terminology for each situation

6. EXPOSURE FACTORS Image too dark
the film is overexposed - too much mAs or
the film is overpenetrated – too much kVp
So how do we tell which one it is??...
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)

7. EXPOSURE FACTORS Image too light
If the image is too light, the film is underexposed or underpenetrated.
If the background of the radiograph is not black, the mAs was too low
If the bony trabeculae cannot be seen or there are white areas with no density in the ROI, the kVp was too low

8. PROCESSING
Underdevelopment occurs due to diluted, exhausted or cold developer or developing for too short a time
All areas of the film are too light including the background
The finger test can be used! Put finger behind a black, non-patient area. If you can see your finger, the film is underdeveloped.

9. REMEDY 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

10. PROCESSING
Overdevelopment occurs when the developer is too hot or the film is in for too long
The unexposed silver halide crystals are converted to metallic silver resulting in development fog (a uniform darkening of the film)

11. TOO MUCH RADIATION vs OVERDEVELOPMENT
Both make the film too dark
In the metal marker area, overexposed films will still be white, whilst overdeveloped films will be darkened
Both an underexposed radiograph & an underdeveloped film have grey background

12. REMEMBER
If the radiograph is too dark, you may still get enough diagnostic information using a bright light to view it (not the most optimal situation) If the radiograph is too pale, it is NOT diagnostic! IF THE ROI IS UNDEREXPOSED OR UNDERPENETRATED, REPEAT THE RADIOGRAPH

13. RADIOGRAPHIC CONTRAST
The difference between various shades of grey (densities) on the film

14. CONTRAST
High contrast = white image on a black background with few shades of grey
High contrast = low latitude
High contrast doesn’t allow a large range of anatomy to be visualised
If the kV was too low & there was insufficient penetrating power, there will be no bony trabeculae & there will be areas of white on the film where no x-rays reached the film

15. CONTRAST Low contrast = the film has too many shades of grey
Described as a ‘flat film’
The higher the kV, the lower the contrast
Fogging can also contribute to low contrast
Underdevelopment can also result in a ‘grey, flat’ film

16. SHARPNESS
“The clarity of structures visible on a radiograph” Image sharpness can be affected by a large number of factors

17. Movement Unsharpness
A common cause on abdominal & chest views due to respiration or struggling
Can occur if the tube stand or plate moves
Can be minimised by sedation or anaesthesia of the patient
Use sandbags, troughs etc
Keep exposure time as low as possible

18. Scatter Radiation
Unsharpness caused by scatter radiation occurs when x-raying thick or dense tissues
This can be reduced by collimating to the ROI
Use a grid

19. Fog Darkening of the film unrelated to the radiographic image
Fog is an unwanted increase in density
Fog reduces radiographic contrast
Fog makes it look as if ALL the image is being viewed through a grey veil
Fog can be caused by:
scatter radiation, exposure of the film to radiation, exposure to white light, unsuitable safelight filter, safelight too close to workbench, prolonged storage, overdevelopment

20. Poor film-screen contact
Caused by a shrinkage of the felt pad behind the intensifying screens
Also, there could be an artifact in the cassette & the felt pad will cause blurring in the same spot
This will decrease image sharpness

21. Focal Spot Size
Fine focus provides fine definition but limits your exposure
Broad focus allows higher exposure but some detail is lost
This may be minimise this by keeping the object-film distance (OFD) as short as practicable & maintaining a reasonably long FFD

22. Magnification & OFD
The diverging x-ray beam produces some magnification
Increasing magnification leads to an increased penumbra effect
This may be minimised by positioning the animal as close to the cassette as possible
A standard FFD of 100cm or 115cm maximum is preferable

23. BASIC ERRORS IN RADIOGRAPHY
No coning
No identification
No left or right markers
Not centering on the ROI
Wrong FFD
Wrong exposure factors for the film/screen type
Not having the x-ray beam perpendicular to the cassette

24. BASIC ERRORS CONTINUED
Basic grid problems
Endotracheal tube still in
Collar still on dog/lead on the x-ray cassette
Double exposure
Wet fur or contrast agent in fur or on sheet under animal
Hands, opaque restraint devices or lead gloves in the radiation field

25. GRID DOUBLE-CHECKS Centre the beam to the centre of the grid
Be sure the grid is level (see diagram in handbook)
If a focussed grid is used:
Use correct FFD
Place the ‘tube side’ upwards
Use correct exposure factors for grid type

26. TECHNICAL ERRORS
X-ray film is also sensitive to extraneous pressure, fumes, humidity, rough handling & temperature
For these reasons, unexpected artifacts, technical errors sometimes appear on radiographs
Can happen to manually or automatically processed films
Repeat rates can be as high as 10%! Causing undue waste of time, money & additional radiation to patients & staff

27. TECHNICAL ERRORS
A technical error may destroy the diagnostic value of the radiograph
Or radiographic quality may be diminished, but deemed useable
This compromises the whole diagnostic quality of the examination
Some errors are sporadic; some regular
Recognition of a pattern is helpful when searching for the cause & corrective action

28. TECHNICAL ERRORS Artifacts may be classified on their appearance:
Is the artifact concentrated to a single area or spread throughout the film?
Is the artifact clear (radiolucent) or dark (radiopaque)?
Is it cloudy?
Does the artifact appear to be on the surface of the film?
By this process, most artifacts can be recognised & corrective action taken to eliminate them

29. TECHNICAL ERRORS
Refer to chart labelled “What to Ask When Dealing With Film Artifacts?” Page 147 in your student handbook

30. TROUBLE-SHOOTING
For trouble-shooting and problem solving please refer to pages in your student handbooks

31. ARTIFACTS
There are examples of some common radiographic artifacts on Page 154 in your student handbooks!