1. Darkroom and Film Processing
Rad Tech A – Week 9 Spring 2009

4. Darkrooms – Still Necessary?
Darkrooms are necessary for manually fed processors and daylight processors.
-Loading automatic film processor magazines.
Necessary for conducting certain quality control tests (daily sensitometric strip).

5. Darkroom

6. Darkrooms 4 Basic Functions
Number 1 Function
Storage
Unexposed film

8. Purpose of Film Processing
DARKROOM FUNCTION # 2
Purpose of Film Processing
Change silver halide crystals from film emulsion (after exposure to x-ray or light photons) to black metallic silver.
Latent image (invisible until processed) is developed into a Manifest image.
Improper or careless processing can cause poor diagnostic quality.

9. Manual Feed Processor

10. Hand Processing in the Early years
Strong smell of chemicals
Messy
Time comsuming

11. 1956 – first roller transport 6 minute processing time

12. Processing Time
3 minutes seconds

13. Processing Film Table top Processors
Can process as fast as 60 seconds
TABLE TOP PROCESSOR

14. PROCSSING CHEMICALS Solutions are PRE- MIXED
Outside Company usually provides service-
Weekly or monthly
Solutions should be replenished as necessary & changed regularly
Solutions must be monitored (Daily QC strip).

15. Replenishment tanks

16. TABLE TOP FILM DUPLICATOR to MAKE COPIES OF FILMS

17. WILL THIS WORK ????

18. Daylight Processor

19. Function # 3: Handling of Film

20. UNLOAD EXPOSED FILM

21. Pass Box

23. LOAD CASSETTE

24. Function # 4: Film Identification
Pt name
Exam date & time
Pt x-ray number
Pt Birthday/DOB
Rt or Lt marker
Optional
Exam type
Dr. Name

25. FILM ID PRINTER Name of patient place on top
Cassette is “flashed” with name – can be done before or after image is taken
Must be done BEFORE
PROCESSING
FILM

26. AUTOMATIC PROCESSING WASHER DEVELOPER DRYER FIXER REPLENISHMENT SYSTEM
TRANSPORTATION SYSTEM
DEVELOPER
FIXER
WASHER
DRYER
REPLENISHMENT SYSTEM

27. Automatic Processor

28. Processor Chemistry Overview
Developer – converts latent image into manifest image
Fixer – clear the film of unexposed, undeveloped silver bromide crystals, promotes archival quality
Wash – rid the film of residual chemicals

29. Developer Solution (6 Ingredients)
Reducing Agent: reduce exposed silver halide to black metallic silver
-Hydroquinone (Blacks)
-Phenidone (Grays)
2. Activator: softens gelatin, maintains alkaline pH (increase pH)
-Sodium Carbonate

30. Developer Solution
3. Hardener: prevents damage to the film from over swelling of gelatin in automatic processors.
-Gluteraldehyde
4. Preservative: Antioxidant that prevents oxidation of developer
-Sodium Sulfite

31. Developer Solution
5. Restrainer: prevents chemical fog in new developer
-Potassium Bromide
6. Solvent: dissolves & ionizes the developer chemicals
-Water

32. Fixer Solution (5 Ingredients)
Clearing Agent: dissolves undeveloped silver halide
-Ammonium Thiosulfate
2. Tanning Agent: shrinks, hardens, preserves emulsion
-Aluminum Salt

33. Fixer Solution
3. Activator: neutralizes developer, maintains acidic pH (decrease pH)
-Acetic Acid
4. Preservative: prevents oxidation, prolongs solution life
-Sodium Sulfite
5. Solvent: dissolves other ingredients
-Water

34. Wash Rid the film of residual chemicals
Residual chemicals on the film will discolor radiograph over time.
Cold water processors are less efficient in removing chemicals – Warm water processors much better.
Agitation during wash process is essential

35. Fixer Retention (Not Washed Off)

36. Transport System Components
Feed Tray
Rollers (Different Assemblies):
1. Entrance
2. Deep Racks
3. Turnaround
4. Crossover
5. Squeegee
6. Dryer
Receiving Bin

37. Transport System (Rollers)
Entrance
Crossover
Feed Tray
Squeegee
Deep Racks
Dryer
Turnaround

38. Processor (Top View)

39. Replenishment System
Main function: Keep solution tanks full and assure proper solution concentration.
As film is introduced into processor, sensor initiates solution replenishment
Right & wrong way to feed in film
-Feed in along short edge

40. Transport System in Automatic Processors
Conveys the film through different solutions (sections) by a series of rollers driven by gears, chains & sprockets.
Done at a prescribed speed – determines length of time the film is in each solution

41. Temperature Regulation
Main function: To control the temperature of each section of the processor.
Developer – most important solution to regulate
Usually between 92 degrees and 95 degrees
Thermostatically controlled

42. Recirculation System
Provides agitation necessary for uniform solution concentration

43. Wash & Dryer Systems
Wash: Provide thorough removal of chemical solutions from the film.
-Archival film quality
Dryer: Removes water from film by blowing warm, dry air
-Between 120 degrees & 130 degrees F.

44. Silver Recovery
About ½ of the film’s silver remains in the emulsion after exposure & processing.
Other ½ (unexposed silver) is removed from the film during fixing process.
Silver is toxic to public water supply – must have proper disposal. Silver can be harvested from the fixer tank and recycled.

45. What is in the Darkroom?

46. Darkroom Contents Loading Bench Film Bin Film I.D. Printer Safelights
Pass Box
Light-tight Room
Ample ventilation
Warning Light outside room
Lockable Door
Wall Shielding if adjacent to x-ray room
Walls painted with light color to reflect safelight

48. Darkroom Equipment

49. SAFELIGHTS

50. Safe Light 15 Watts Red filter
Must be 3-6 feet from counter top or feed tray of processor
Used to be amber or orange filter

51. Darkroom Summary

52. Summary & Questions

53. X-ray Cassettes cross section review layers
What are the
4 layers? Of
FILM &
SCREENS ?

54. Film cross section

56. RTA LAB 2 Next Week : PROCESSING & SCREEN EXPOSURE
IONIZING LAB
INTENSIFYING SCREEN
DARKROOM
PROCESSING & CHEMISTRY
COMPLETE IN CLASS WORKSHEET