dental students

1. Good
afternoon…
Dr.Pallavi sinha
Reader
Department of oral medicine and radiology
Rama dental college and hospital
Kanpur

2. PROCESSING X-RAY FILMS

3. Processing is a collective title given to
a series of operations carried out in the
darkroom which effect chemical changes
in the exposed radiographic film making
the invisible latent image contained in
the sensitized film emulsion into a visible
permanent radiographic image.

4. FORMATION OF LATENT IMAGE
 Film emulsion consists of photosensitive
crystals containing primarily silver bromide
suspended in a vehicle and layered on a thin
sheet of transparent plastic base.
 The crystals are chemically sensitized by the
addition of trace amounts of sulfur
compounds, the sulfur compounds play a
crucial role in image formation.

5.  Along with physical irregularities in the
crystal produced by the iodide ions, sulfur
compounds create SENSITIVITY SITES.
 Each crystal has many sensitivity sites which
begin the process of image formation by
trapping the electrons generated when the
emulsion is irradiated.

8. TYPES OF PROCESSING
 AUTOMATED
 MANUAL

11. BASIC STEPS IN MANUAL
PROCESSING
Film processing involves the following procedures:
 Immerse exposed film in developer.
 Rinse film in a water bath.
 Immerse film in fixer solution.
 Wash film in water bath.
 Dry film and mount for viewing.

14. DEVELOPER SOLUTION
 The developer reduces all silver ions in the
exposed crystals of silver halide to metallic silver
grains.
 Variations in density on the processed
radiograph are the result of different ratios of
exposed and unexposed crystals.
 If developer remains too long in contact with
silver bromide crystals that do not contain latent
image, it slowly reduces these crystals also
thereby overdeveloping the image.

17. FIXER SOLUTION
 The primary function of the fixing solution is
to dissolve and remove the undeveloped silver
halide crystals from the emulsion.
 The second function of fixing solution is to
harden and shrink the film emulsion.

19. AUTOMATIC PROCESSING

20. ADVANTAGES
 Processing time is shortened from
60 to 90mins 1.5 to 5mins.
 Constant film quality due to fixed processing cycles.
 Less floor space or counter top space required.
 Darkroom can be eliminated when the automatic
processor is equipped with a daylight loader.

21.  Less equipment is required such as film racks,
film hangers, film dryers timer and
thermometer.
 Wet reading of films is eliminated.

22. HOW DO AUTOMATIC PROESSORS WORK?
 It usually consists of a series of rollers that
transport the films through the various
solution sections.
 It requires only about 4 to 6min to develop
fix wash and dry a film.

23. FUNCTIONS OF ROLLERS
 Transport the film through each section.
 Provides a massaging action that contributes to the uniform
distribution of chemicals on the film emulsion.
 Special squeegee rollers remove processing solutions from
the film surfaces and reduces amount of solution carryover.
 Squeegee rollers in the wash section remove most of the
water from the emulsion before transport of the film to
drying section.

24. AUTOMATIC PROCESSING SOLUTIONS &
REPLENISHMENT
 The solution is similar with a few differences:
 A hardening chemical glutaraldehyde is added
to the conventional developer to prevent the
emulsion from softening & sticking to the
rollers.
 Sulfate compounds are also added to minimize
the swelling of emulsions so the films can be
transported by rollers uniformly.

25. OTHER METHODS OF PROCESSING
 MONOBATH METHOD
 In this method the developer and fixer are
combined in one solution, the fixer is alkaline
and doesn’t neutralize the developer.
 This monobath solution is injected into a special
waterproof film packet and the film is
developed by simply rubbing the film packet,
there is no need for a darkroom.

27. ADVANTAGES:
 Ideal for RCT or in cases of quick spot
diagnosis.
DISADVANTAGES:
 Alkaline type of fixer very rapidly oxidizes
under atmospheric conditions.
 Results are not satisfactory as fixing starts
while the developing process is still in
progress.

28. DAY LIGHT METHOD
 It is carried out in a special device provided with
safelight filters & 2 glove like compartments
through which the operator puts his/her hands &
develops the film.
 The films are opened and processed in subdued
daylight, no need for darkroom.
 The emulsion consists of a yellow dye & the film
appears yellow and black instead of the
conventional blue white and black.

29. SELF DEVELOPING FILMS
Recent advance in manual processing, X-ray
film is presented in a special sachet
containing developer and fixer.
ADVANTAGES:
 No darkroom needed
 Time saving.

30. DISADVANTAGES:
 Poor overall image quality
 Image deteriorates rapidly over time.
 No lead foil in film.
 Film packet is very flexible.
 Difficult to use with positioning holders.
 Relatively expensive.

31. DARKROOM EQUIPMENT
REQUIREMENTS :
 Should be at least 4x5 feet.
 Must be lightproof- light tight door or door less
maze can be used.
 Should be well ventilated.
 Adequate counter area must be present.
 Adequate storage space.
 Maintenance of temperature and humidity levels.

32. SAFELIGHTING

33. Safelighting : Is low intensity illumination of
relatively long wavelength that does not
rapidly affect open film but permits one to
see well enough to work in the area.
 X-ray film emulsions are primarily sensitive
to blue and green light and are less
sensitive to light in the opposite region of
the spectrum (yellow, red).
 Safe lights are safest when made with
amber or red filters.

34. LOCATION:
 Above the work area on the wall behind the
processing tank and somewhat to the right of
the fixing tank.
 It should be mounted at least 4 feet above the
surface where films are opened and should
have a 15 watts bulb.
DURATION:
Work time should be within 5 to 8min.
TYPES:
Kodak GBX-2(red) ML-2(light orange).

35. Test for checking unsafe
illumination
Penny test

36. RAPID PROCESSING SOLUTIONS
These solutions typically develop films in
15sec and fix them in 15sec at room
temperature.
COMPOSTION: Similar to conventional but
higher concentration of hydroquinone and
more alkaline pH.
DISADVANTAGE: Contrast is less and films may
discolor over time.

37. CHANGING SOLUTIONS
 Exhaustion of the developer results from
oxidation of the developing agents, depletion
of the hydroquinone & build up of bromide.
 When fixer becomes exhausted silver
thiosulfate complexes form & halide ions
build up.

38. REPLENISHMENT
 With regular replenishment solutions may last 3
or 4 weeks before they must be changed.
 In automatic processors there is an automatic
replenishment system.
 As with manual 8 ounces of fresh developer &
fixer should be added /gallon of solution/day.
 This assumes an average workload of 30 intraoral
or 5 extra oral films per day.

39. MANAGEMENT OF RADIOGRAPHIC WASTE
 Many communities have laws governing disposal
of wastes derived from the Federal Resource
Conservation & Recovery Act of 1976.
 Primary ingredient of concern is dissolved silver in
fixer and lead foil.
 Silver maybe recovered from fixer by:
a) Electroplating method
b) Metallic replacement

40. THANK YOU...