no thing is written

3. Processing of
Dental X-ray Films
Hisham Abbas
Ass. Professor & Consultant
Oral & maxillofacial Radiology Department

4. Processing
It is a chemical process by which the
invisible latent image formed on the
exposed film is converted to a visible
image from which diagnostic information is
obtained.

5. Film emulsion Latent image
Visible image
exposure
to radiation
processing of
the exposed film

6. Latent image
It is the pattern formed by the
interaction of x-rays (or light) with the
silver halide crystals in the emulsion.

7. Silver Halide crystal contains:
1. Silver bromide molecules (Ag Br) (80-90%)
2. Silver iodide molecules (Ag I) (1-10%).
3. Few Free silver ions ( Interstitial Ag ions = Ag+ )
(present in the spaces between the crystalline lattice atoms)
4. Trace amounts of Sulfur Containing Compounds

8. Sensitivity sites are created by
1. Silver iodide molecules
2. Trace amounts of Sulfur Containing
Compounds binding the surface of the crystals.
Its function is to start the process of image
formation after the emulsion is irradiated.

9. amalgam
enamel
dentin
pulp

10. No x-ray photons penetrate the amalgam
x-ray photons penetrate the enamel
x-ray photons penetrate the dentin
x-ray photons penetrate the pulp
Film
Object
X-ray
According to the Selective Penetration Phenomenon
of x-rays:

11. No x-ray photons penetrate the amalgam
x-ray photons penetrate the enamel
x-ray photons penetrate the dentin
x-ray photons penetrate the pulp
Film
Object
X-ray
Unexposed Crystal
Partially Exposed
Crystal
Totally
Exposed Crystal
According to the Selective Penetration Phenomenon
of x-rays:

12. Formation of the Latent Image
The crystals exposed to x-rays are ionized
and the silver and bromide atoms form ions.
Ag Br Ag+ + Br -
Br - Br2 (gas) + e -
x-ray Photons

13. -Ag- Br- Ag- Br- Ag
-Ag- Br- Ag- Br- Ag- I- Ag
-Ag- Br- Ag- Br- Ag- Br- Ag-Br-
-Ag- Br- Ag- Br- Ag- Br-
- Ag- I- Ag- Br-
Ag+
Ag+
e-
Ag
Sensitivity Site
Sulfur Containing Compounds
latent image sites

14.  The collection of latent image sites over the
entire exposed film constitutes the Latent
Image.

15. Latent Image
Many x-rays
penetrate and
expose many silver
halide crystals
Fewer x-rays
penetrate and not as
many silver halide
crystals are exposed
Few, if any, x-rays
penetrate; silver
halide crystals not
exposed
Air/soft tissue Bone/teeth Amalgam/gold
Totally, Partially or Non - Ionized crystals

16. AgBr
Ag
Ag+ Br-
Ag
Ag+ Br-
AgBr
Totally
Exposed Crystal
Partially Exposed
Crystal
Unexposed
Crystal

17. Formation of the Visible Image
Film processing converts the latent image
into visible image.

18. Film processing
Five practical steps :
1. Developing: Immerse exposed film in developer.
2. Rinsing: Rinse film in water bath.
3. Fixation: Immerse film in fixer.
4. Washing: Wash film.
5. Drying: Dry film and mount for viewing.

19. 1] Developer Solution:
The developer reduces all silver ions in the
exposed crystals (Totally & partially) of silver
bromide (with a latent image) to metallic
silver (Ag+ Ag).
To produce a diagnostic image, this reduction
process must be restricted to crystals
containing a latent image site (No effect on
unexposed crystals).

20. AgBr
Ag
Ag+ Br-
Ag
Ag+ Br-
AgBr
Totally
Exposed Crystal
Partially Exposed
Crystal
Unexposed
Crystal
AgBr
Ag
Latent
Image
Optimum
Development
Ag
Ag
Over
Development
Ag Ag

21. Air/soft tissue Bone/teeth Amalgam/gold
Developing
Development centers converted to
black metallic silver

22. Air/soft tissue Bone/teeth Amalgam/gold
Developing (continued)
Entire crystal converted to
black metallic silver

23. 2] Rinsing:
Rinse the film for 15-20 seconds.
The function is to:
a. Neutralize and remove the alkaline activator of
the developer.
b. Stopping the developing process

24. 3] Fixing Solution:
The function of the fixing solution is to:
1. Remove undeveloped silver halide crystals
from the emulsion making film clear in this
area (primary function ).
as their presence will cause the film to be
opaque and non-diagnostic.
2. Harden the film emulsion.

25. Totally
Exposed Crystal
Partially Exposed
Crystal
Unexposed
Crystal
AgBr
Ag
Fixation
Ag
AgBr
Ag
Optimum
Development
Ag

26. Air/soft tissue Bone/teeth Amalgam/gold
Fixing
Unexposed crystals removed
from film

27. 4] Washing of the Processed
Film:
 In a sufficient flow of water for an adequate time
 Assure removal of all processing chemicals which
may discolor the radiograph.
5] Drying:
 Makes the film ready for interpretation
 Facilitates film handling without mechanical

28. Latent Image
Fixation
Before Exposure
Optimum
Development

29. Processing is accomplished inside
The Processing Room
(The Darkroom)

30. The Processing Room
 It is the room in the dental office where
x-ray film can be handled and processed
to produce a diagnostic radiograph.

31. Requirements:
1. Size:
The size is governed by:
The number of working personnel.
The type of processing equipment used.

32. Requirements:
2. Site:
 Near operation area
 Near (but well protected) area of film exposure

33. Requirements:
3. Ventilation and Temperature
Well Ventilated:
to expel heat and moisture as well as vapors
from processing solutions.
AdaquateTemp.:
to maintain optimum processing condition

34. Requirements:
4. Light tight
•Windows & blinds must fit closely
•The entry door must be either:
1.Light-tight door with lock inside
2.Door-less maze

35. Requirements:
5. Clean

36. i- Safe light:
Low-intensity illumination of relatively
long wave length that does not rapidly
affect open films but permits operators to see
well enough to work in the area.
Requirements:
6. Equipments:

37. 15 watt
long wavelength
(Red - Yellow)
15-watt
4 feet
5 minutes
1-2 (the size of the room)
Requirements of safe light include:

38.  Safe light should be regularly checked for
any cracks on the filter
 The dark room should be checked for
unsafe illumination

39. film fogging
Improper safelighting, light leak

40. The Coin Test (Safelight Test)
Problem
Everything OK
Wait for 5 min.

41. If there is a problem,
repeat it with turning safe light off
Problem in Light leakage
Problem in safe light
Wait for 5 min.

42. ii- Room light
• Incandescent room lighting is required
for cleaning, stocking materials, and
mixing chemicals.
• No Fluorescent light ------- after glow.

43. iii- Processing tank:`
•Master Tank
•Insert Tanks (1ga-
3.8 lit)
•Source of running
water
•Overflow pipe
•Master Tank must be
covered
•(to Reduce oxidation -
Minimize evaporation -
prevent accidental light
exposure)
•Material (porcelain-
stainless steel)

44. iv. Thermometer:
•Used to determine temperature of processing
solutions

45. Clipped or Floats
in master tank

46. v. Timer:
•Gives sound or fluoresce light within safe
range.
•Used to determine duration of insertion in
processing solutions

47. vi. Film hangers:
Intra-oral
(1- 14 clips)
Extra-oral
(1 film)

49. vii. Dryer:
•Cabinet Dryer
•Electric fan
•Drying Racks
with drip trays

50. Darkroom storage space for:
chemical processing solutions
film cassettes
viii. Storage space:

51. Methods of Processing

52. Methods of Processing:
1] Conventional or Manual Processing:
a. Visual or inspection method.
b. Fixed time - temperature method.
2] Speed processing:
a. Automatic processing.
b. Rapid processing chemicals.
c. Self-contained processing solutions.
d. Injectable films.
e. Polaroid - Land method.

53. 1] Conventional or manual processing
a) Visual or inspection method:
- Films are immersed in the developing
solutions and removed every now and then
to be checked in the safe light until the image
of radiographed structures is acceptably
visible.
- Films are rinsed for about 30 seconds.
-Films are placed in the fixer solution with
agitation.
- Films are washed in clean running water.
- Films are then hanged to dry.

54. b) Fixed time and temperature method:
 The time of developing varies with the
temperature of the processing solution for each
type of film.
 The higher the temperature, the less the time
required for developing and vice versa.

55. b) Fixed time and temperature method:
 Follow the instructions listed on a time-
temperature table chart supplied by the
manufacturer of the processing solution.
 Standardized
Method with Little
Errors

56. Manual Processing
Mixing valve
Fixer
insert tank
Developer
insert tank
overflow tube
drain
waterbath
(large tank)
water inlet
Cold
Hot
lid

57. In case of darkroom unavailability, manual
processing may be carried out using a
daylight loader
Rubber
cuff
Lid

59.  Placed in area of reduced lightening.
 For manual processing or as an
extension compartment connected to
automatic processor machine.

61. 2] Speed processing
a. Automatic processing.
b. Rapid processing chemicals.
c. Self-contained processing solutions.
d. Injectable films.
e. Polaroid - Land method.

62. 2] Speed Processing:
Automatic processing
 Unwrapped film is transported automatically
by a machine through rollers.

63. Film
Exit Dryer
(heater, fan)
Film
Entry
Wash
Automatic Processor
Fixer
Developer

64. Automatic Processing

65. Dark Room or Daylight Loader

68. The processing steps are the same as
for manual processing except that the
rinsing step between the processing
solutions is eliminated…??????

69. Advantages:
 Rapid & Time saving (2-5 min)
 Ease of use
 Standardized processing condition
 No Dark room

70. Reducing processing time
through:
 Elimination of Rinsing step.
 Higher Temp. of solutions (Mod. in processing sol.)
 Higher Conc. of solutions
 Regular replenishment (Manually or Automatically
from self contained reservoirs)
Replenishment: It is the addition of a more concentrated
solution of the processing solution than the original one.

72. Disadvantages:
 High Cost
 Regular maintenance & cleaning (Marks on film)
 Must process minimum number of films daily
 High Temp. -------- fogging & deteriorates sol.
 Dark room back up is needed just in case of it is
broken down.

73. b) Rapid Processing Chemicals:
 They are processing solutions of the same
formulation as conventional processing but often
are more concentrated.
 They will typically develop the film in 10 to 30
seconds and fix it in 1 to 2 minutes.
 They are especially used in endodontics and
emergency conditions
 They do not give the same degrees of contrast
as conventional methods.

74. c) Self-contained processing solutions
Sachet containing
Developer & Fixer
Film Packet

75. Develop. (15sec.) –Fixation--Washing (10 min.)
c) Self-contained processing solutions

77. Advantages:
 Ease of technique (No Dark room)
 Time Saving

78. Disadvantages:
 (Relatively Fogged)
 Further Fixation is needed to prevent
loosing of details

79. d) Injectable intra oral films
 The processing solutions are injected into the
closed packet which is supplied with an
injectable site
 Packets have NO lead foil or black papers
 Same adv. & disadv. as self-developing films

80. Composition of
Processing Solutions

81. Function
Chemical
Ingredient
- Converts exposed AgBr crystals to black metallic silver.
- Slowly generates the black tones in the image.
- It is temperature sensitive
(Inactive below 60 of (15.5oC)
(Very active above 80 of (26.5oC)
- Converts exposed AgBr crystals to black metallic silver.
- Quickly generates the grey tones in the image.
- It is temperature insensitive.
Hydroquinone
- Elon
(metol)
Developing
Agent
- Provides alkaline pH necessary for developing agents.
- Softens gelatin to swell so that the developing agents can
diffuse more rapidly into the emulsion and reach the AgBr
crystals.
Sodium
bicarbonate
Activator
Developer composition

82. Function
Chemical
Ingredient
- Antioxidant protects the developer from
oxidation by atmospheric oxygen thus extends
its useful life.
- Combines with the brown oxidized developer
to produce a colorless soluble compound.
Sodium sulfite
Preservative
- Restrains development of unexposed silver halide
crystals (controls activity of the developer).
- Acts as anti-fog agents and increases contrast.
Potassium
bromide
Restrainer
Developer composition

83. Function
Chemical
Ingredient
- Remove all undeveloped
crystals from the emulsion.
Sodium thiosulphate
Ammonium thiosulphate
Fixing agent
- Neutralizes the alkaline
developer and stops further
development.
Acetic acid
Acidifier
- Prevents deterioration of the
fixing agent.
Sodium sulfite
Preservative
- Shrinks and hardens the
gelatin in the emulsion.
Potassium Alum
Hardening agent
Fixer composition