PROCESSING OF X RAY FILMS
Dr Mohd Malik
Format
1. Latent Image Formation
2. Dark Room
3. Processing Solution


Developer
Fixer
Latent Image Formation
 Film emulsion largely constitutes Silver
Halide Crystals
 Free Interstitial Silver Ions
 Sulphur compounds – Sensitivity Site
 Sensitivity site begin the process of image
formation by trapping electrons
Latent Image Formation


X ray Photons
Silver Halide crystals
1. Compton Effect
2. Photoelectric Effect
Latent Image Formation
 Removal of an e- from




bromide ions
Bromide ion
Bromine
Free eSensitivity
Site
Here e- imparts –ve
charge
Silver ion+sensitivity site
 Neutral Metallic Atom
Latent Image Formation
 Metallic silver at each latent image site renders
the crystals sensitive to development and image
formation
 Larger the aggregate of metallic silver
 More sensitive is the film
 Developer
metallic silver
latent image
Metallic
silver
grains
 Fixer removes unexposed, underdeveloped silver
halide crystals
Processing Solution
1. Developer Solution
2. Water Bath
3. Fixer Solution
4. Water Bath
Developer Solution
Silver halide
Metallic silver
 Reduces
 Neutral silver ions
 Electrons
crystalline silver
catalyzer
ions
 This is how the reaction process is –
 Developer + film
No reaction
(initially)
 Developer + film
density increases
rapidly
 Then again the reaction slows down.
Composition Of Developer
Developer
1.


Pyrazolone Derivatives(1 – Phenyl 3
Pyrazolidine)
Hydroquinine – it provides an e- to reduce oxidized
Phenidone to its original form.

Function/use – Is the main component of developer
solution which helps in developing the x ray film
2. Activator – sodium or potassium hydrozide

Developer is active at alkaline pH
Function/use – It keeps the developer solution in active
state and at alkaline pH as developer gives electrons
during x ray film developing
Developer Solution
Preservative – Sodium Sulfite.
Function/use –
3.



Prevents developer from getting oxidized
It combines with brown oxidized developer to make it
colourless
4. Restrainer – potassium bromide or Benzotriazole
Function/Use –


It is more effective in reducing the unexposed silver halide
crytals from getting developed
If the film is kept for too long in the developer solution
then developer solution can reduce even exposed crystals.
Developer Replenisher
(Additioner)
 After developing 30 periapical or 5 panoramic
films the developer solution becomes weak as all
the electrons in the developer solution are used
 Hence 8 ounces of fresh developer solution is
added per gallon (3.8 liters) of developing
solution.
 In order to replenish (add) the solution some
amount of old solution is to be discarded.
 Care should be taken in handling the solutions
and proper temperature should be maintained.
Fixer Solution – General
Function/Use
 Is to dissolve and remove the underdeveloped
Silver Halide crystals from film emulsion.
 It hardens and shrink the film emulsion.
 Unexposed silver halide crystals form opaque film
 Unexposed films make a dark and non –
diagnostic radiograph
Fixer Composition
1. Clearing Agent – Aquous solution of Ammonium
Thiosulphate or Hypo.
 Function/Use
 It dissolves silver halide grains
 It forms stable water soluble substances with silver
ions
 It does not have a rapid effect on metallic silver
grains but excessive fixation results in gradual
loss of film density
2. Acidifier – Acetic Acid is used which maintains
the fixer solution at 4 – 5 pH
 Function/Use
 Is required to promote good diffusion (entry) of
Thiosulphate (main fixer conponent) into the x ray film
emulsion
3. Preservative – Ammonium Sulfite
 Function/Use – It prevents oxidation of
Thiosulphate solution
4. Hardener – Aluminium Sulfite
 Function/Use –
 Aluminium complexes with the gelatin during fixing
and prevents damage to gelatin during subsequent
handling.
WASHING
 Is used to ensure the removal of Thiosulphate
ions and its compounds.
 Washing temperature should be maintained
to 600 degrees Fahrenheit below which its
efficiency declines
 Washing should be done under running
water.
Processing Technique
 1903 – Edmund KUlls introduced processing tanks
 1920 – Reliable film hangers were made available
 Requirements Of Processing Tanks: They must have a hot and cold running water
facility within them to maintain temo. 60o to 75o F
 Should be made of non reactive material to the
processing solutions and should be easily cleansible
Processing Tank
 Master tank – 20 x25
cm (8 x 10 inches)
 Function/Use – It
serves as a water jacket
for two movable
inserts to fit inside.
 Insert tanks usually
hold 1 gallon or
3.8Liters
Processing Tank
 Developer insert tank is
at left in master tank
 Fixer insert tank is at
the right in the master
tank
 Master tank has a
cover to protect the
solutions from getting
oxidized.
Processing Technique
1. Manual


Time Temperature Method
Visualization Method
2. Automatic Processors
Time – Temperature Method
 It uses a thermometer which is placed in the
developer tank and a stop watch timer which helps
to calculate the time for which x ray film should be
kept inside the developer and fixer tanks accordingly
 Thermometer –
 Should be clipped to processing tank
 It should contain metal or alcohol to avoid contamination
by mercury incase of accidental breakage.
 Timer –
 An interval timer is needed for controlling developing and
fixing time
Time – Temperature Procedure
 Once operator enters inside the x ray room he should
perform the following actions –
1. Replenish the solution – if the solution was not altered
last time
2. Stir solution – with a wooden stick in order to mix all
components in the solutions
3. Mount x ray film on hangers
4. Set timer – 680F – 5min…… 800F – 21/2 min
5. Develop
6. Rinse
7. Fix
8. Wash
9. Dry
Visual Method
 Here the operator evaluates by visualizing the
film under the safe light.
 Advantages –
 Desired contrast can be obtained
 Temperature – time variations can be
handled
 Operator Satisfaction
 Disadvantages –
 Operator sensitive
 Manufacture recommended contrast cannot
be reached
 Operator needs to stand till film develops
 Manufacturer cant be questioned for any
variations
Automated Film Processors
 1910 – Automated film
processors
 They have light
shielded compartment
to unwrap the film
 the film is passed
under rollers
Automated Film Processors
 Advantages –
 Less time consumption – 4 to 6 min.
 Need of specialized dark room eliminated
 Portable
 Disadvantages –
 Dificult to maintain
 Roller marks are common
 Machine problem in middle
 Cost
Radiographic Waste
 Silver can be recovered from fixer by
 Metallic Replacement ( uses cartridge )
 Electroplating Method ( 2 electrodes )
 Lead Foil
 Countries biohazard team should be
contacted for proper disposal.
Recent Advances
 Speed F films
 Duplicating Films
 Self Developing films
 Films with suresoft
border.
Thank You
 Any Questions ?