1. THE FINAL STEP: IMAGE PROCESSING
Lavin: Chapter 8
CTVT:

2. Learning Objectives Understand darkroom specifications
Understand the purpose of the various chemicals used in x-ray processing
Distinguish between manual and automated processing
Know the purpose of the darkroom safelight
Be able to list the steps of film processing

3. Film Processing Developing and fixing an exposed x-ray film
Proper processing is vital to the production of a quality radiograph.
Most mistakes made in veterinary radiography are related to processing
Processing can be done either manually or automatically.
Steps are basically the same..

4. The Darkroom Three qualities of a good darkroom: Clean Organized
Lightproof

6. The Darkroom Should be separate from radiographic suite
Should be used for only one purpose - processing exposed radiographs
Most of work in darkrooms is with minimal light (hence the word “dark”).
Layout should be organized to help reduce possibility of film damage.

7. Darkroom Cleanliness & Organization
Should be clean –
The only room where intensifying screens and x-ray film are exposed to the air
Should have proper climate control
Chemicals should be changed, replenished, maintained, and mixed carefully & safely.

8. Dry Side of Darkroom Where cassettes are unloaded and reloaded.
Countertop should accommodate largest cassette in an open position
Countertop should be easy to clean
Nothing “wet” should be brought to the dry side.
Customary to store film under the dry table in a bin or cupboard.
How should film be stored?
Film hangers for each size film should be hung above the table on the dry side.
Film Storage

9. Wet Side of Darkroom Where actual chemical processing occurs
Hand or manual processing in three tanks.
Developer – Converts the sensitized silver halide crystals into black metallic silver
Crystals were sensitized when exposed to x-rays
Water – Used as a solvent to keep all the ingredients in solution & to wash films
Fixer – Removes the unchanged crystals from the film emulsion, leaving the black metallic silver

10. Manual Processing Tanks

11. Lightproofing Light leaks:
May be hard to perceive
Common sources:
Around entrance door
Ceiling
Phones/watches
Entrance ideally has a double or revolving door
Door should fit tightly in its frame.
Use weather stripping to ensure light proofing.
Door should lock

12. Darkroom Safelight Light will not affect the film.
Human eye needs 5-8 minutes to adjust.
Uses a small-wattage bulb and special filter to eliminate light from the blue and green spectrum.
Bulb is 15 watts or less
Never closer than 4 feet away from work area.

13. Safelights (cont.) Direct - Indirect -
Positioned so darkroom work can be performed without fumbling
Two types of safe-lighting
Direct -
Diffused light that shines directly over a work area such as the dry or wet side of the darkroom
Indirect -
A filtered light directed toward the ceiling and reflected over the entire room
The two types of lighting may be combined.

14. Film-processing Techniques
Two types of processing:
Manual - May take up to an hour to develop
Automatic - Can generally be processed in 90 seconds
Both can produce a quality radiograph.
Feed Tray
Developer – Converts the sensitized silver halide crystals into black metallic silver
Crystals were sensitized when exposed to x-rays
Water – Used as a solvent to keep all the ingredients in solution & to wash films
Fixer – Removes the unchanged crystals from the film emulsion, leaving the black metallic silver

15. Film-Processing Solutions
Film processing consists of five basic steps.
Developing
Rinsing or stop bath
Fixing
Washing
Drying
Manual or automated
Never backtrack or pull film back

16. Film Hangers
Available in two designs:
Channel Hangers
Clip Hangers

17. The Developer Developer - Converts latent image to visible image
Chemicals convert exposed grains of silver halide to black metallic silver.
Amount of metallic silver on film is amplified
Little to no effect on the unexposed silver halide crystals
Developer temperature affects developing time
Consists of developing agents, accelerators, preservatives, restrainers, hardeners, and a solvent

18. Exhausted Developer

19. Film-Processing Solutions
Film processing consists of five basic steps.
Developing
Rinsing or stop bath
Fixing
Washing
Drying

20. The Rinse Bath Rinse bath serves to:
Stop the developing process
Rinses the developer from the film
Prevents carryover contamination to the fixer
After film is in the developer, retains a substantial amount of developer in the gelatin.
If film went straight from developer to fixer, then the alkaline developer would neutralize the acid of the fixer.

21. Over-rinsed film

22. Film-Processing Solutions
Film processing consists of five basic steps.
Developing
Rinsing or stop bath
Fixing
Washing
Drying

23. The Fixer Basic functions:
Removes unexposed silver halide crystals from the film
Unexposed emulsion is removed from film, leaving developed image intact & permanent.
Hardens the image to the base

24. Improper Fixing

25. Film-Processing Solutions
Film processing consists of five basic steps.
Developing
Rinsing or stop bath
Fixing
Washing
Drying

26. The Wash bath Removes all waste chemicals from film
If not washed properly, image will eventually discolor and fade.
Wash in circulating water so both surfaces of film receive water continuously.
Manual processing wash time is normally mins.
A wetting agent bath can hasten drying process

27. Under washed film
Sulfiding

28. No Final Wash Applied

29. Film-Processing Solutions
Film processing consists of five basic steps.
Developing
Rinsing or stop bath
Fixing
Washing
Drying

30. Wet side/Drying area Drying completes the process
Drying Cabinet
Drying completes the process
May use a film drying rack or a drying cabinet
Drying rack should be dust free.
Drying cabinet is a heated forced-air unit that hastens the drying process
Illuminator is recommended on wet side of darkroom.

31. Chemicals Usually concentrated and need to be diluted
Correct preparation matters, or resulting solution may adversely affect the image.
Use caution:
Developer is alkaline, fixer is acidic.
A drop of fixer concentrate can melt the lens of the eye in seconds.

32. Solution Replacement
Used/old chemicals are primary cause of poor-quality radiographs.
Check chemicals every time PRIOR to development of film.
Developer may turn from brown to green.
In general, chemicals should be changed every 4-6 weeks.

33. Automatic Processing Advantages over manual method:
Standardized & consistent
Produces radiograph fast
Reduces labor time
Smaller darkroom space required.
Film is transported through processor by rollers
Rollers can cause damage
Lots of artifacts
Roughly the same procedure as manual

34. Automated Transport System

35. Automatic Processor (cont.)
Chemicals need to be checked and processor warmed up.
Feed films one at a time to prevent sticking together.
Will be signaled by the processor to feed the next film
Don’t forget to turn on vent fan

36. Biologic Growth May have bacterial growth in solutions.
Needs to be controlled.
When changing chemicals, clean tanks as well.
Wash tank of automatic processor should be drained at the end of day to prevent growth.

37. Stuck in processor

38. Films stuck together

39. Folded Film

40. Film Identification Proper Labeling & ID is vital.
All labeling systems should include.
Name/address of hospital or veterinarian.
Date radiograph was taken
Patient identification including name of the owner and patient name, age, sex, and breed.
Can be done via lead lettering, lead impregnated tape, or photo-imprinting labels.

41. Other markers
Right (R) and Left (L) markers are essential to identify size and position of image on radiograph.
May need to label both the front and rear in large animals
If label not a part of film itself, can add later with marker, or scratching into film while still wet.

42. Film Filing
Organized film filing system is needed in veterinary practice
Must be placed in suitable holder and filed appropriately
Should be labeled, numbered if necessary and filed correctly for easy future reference
X-ray logs also help with film identification.