Species: Canine | Classification: Techniques
- Radiography is used as an aid to diagnosis and for monitoring of treatment.
- Automatic processing Radiography: processing.
- Smaller models can be found in many veterinary practices.
- In general produce results:
- More rapidly (90-180 seconds).
- More consistently.
- More easily.
- Dark room must be maintained regularly to ensure consistent production of high quality radiographs.
- Approximately 10 min processing time for a single radiograph.
- Light-proof room.
- Three trays or tanks for chemicals:
- Wash water.
- Film holders either channel hangers or clip hangers if using vertical processing tanks.
- Tank heaters with thermostat to maintain developer at correct temperature.
- Safelight - light of different wavelength (color) than sensitivity of film.
- Dark room divided into dry and wet areas.
- Timer with audible signal to allow accurate timing of development.
- Fresh chemicals: developer and fixer.
Step 1 - Prepare darkroom
- Turn on safelight and turn off mainlight.
- Ensure that door is locked and room is light-tight.
- Allow a few minutes for eyes to become accustomed to the dark.
- Stir the developer and fixer to equalize the temperature and distribution of chemicals throughout the solutions.
- Developer temperature should be 20°C.
Step 2 - Remove fim from cassette
- Under safelighting remove the film from the cassette - handling only by a corner.
- Close cassette to prevent splashing or dirtying of screen.
- Label film if appropriate ie with darkroom identification marker.
- Attach it a film hanger.
Step 1 - Developing
- Immerse film smoothly in the developer solution and note time or set timer.
- Film should remain in developer for 4 min.
Ensure that film is not in contact with adjacent film or side of tank during this process.
- Agitate the hanger with an up and down motion to ensure that the film keeps coming into contact with fresh developer.
- At end of 4 min remove film from tank.
- Development time for non-screen film should be increased by about 1 min.
Do not allow developer solution to run off film back into developer tank.
Step 2 - Rinsing
- Place the film in rinsing tank for at least 10 seconds agitating the hanger throughout.
- Remove film from water.
Step 3 - Fixing
- Immerse the film in the fixer tank.
- After approxiamtely 30 seconds film emulsion should clear.
Do not expose film to white light until emulsion has cleared.
- Standard film should remain in fixing tank for at least 15 minutes.
- Non-screen film has thicker emulsion and fixing may take several minutes longer.
Film may be viewed initially to assess quality after emulsion has cleared.
Step 4 - Washing
- After full fixing place the film in wash compartment for at least 30 min.
Water must be flowing continuously or washing will not be efficient.
Step 5 - Drying
- Remove film from channel hangers to dry to avoid the edges of the film remaining wet.
- Film should be hung in low-humidity, dust-free environment with circulating air.
- Film should not be read finally until emulsion is completely dry.
Step 1 - Reload cassette
- Ensure that hands are clean and dry.
- Double-check that door is locked and that no white light is entering dark room.
- Open cassette and leave on work surface.
- Remove film from film box or hopper.
- Place film on screen in open cassette, taking care that film is not trapped at edge of cassette.
- Replace lid on open box of film or close hopper.
- Close cassette and ensure clips shut tightly.
- Recheck film box or hopper to ensure that they are light-tight before opening darkroom door or turning on light.
Reasons for Treatment Failure
- See Radiography: film faults Radiography: film faults.
- Film incorrectly stored prior to exposure.
- Rough handling of film.
- Room not light-tight → fogging of film.
- Processing performed at wrong temperature.
- Chemicals out of date or exhausted.
- Insufficient developing, fixing or washing time allowed.