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Film processing

Terms in this set (65)

Film processing
Steps that produce a visible image on a dental radiograph, the process is twofold
1. Convert the latent image to a visible image
2. Preserve the image so it is permanent
Film Emulsion
Coating attached to both sides of the film base by an adhesive layer
Highly sensitive to x-radiation
Composed of a homogenous mixture of gelatin and silver halide crystals
Silver halide crystals in the film emulsion
Absorb x-radiation during x-ray exposure
Store energy from the radiation
Latent image
The stored energy forms a pattern and creates an invisible image within the film emulsion known as the latent image.
The latent image remains invisible within the emulsion until it undergoes chemical processing
From Latent Image to Visible Image
A chemical reaction
Reduction
The halide portion of the exposed, energized silver halide crystal is removed
Results in precipitated black metallic silver
Selective reduction
Reduction of energized, exposed silver halide crystals into black metallic silver
Un-energized, unexposed silver halide crystals are removed from the film
The film is placed in developer solution
The film is rinsed in water
The film is placed in fixer solution
The film is washed in water
Visible Image
Made of black, white, and gray areas
Radiolucent
Readily permits passage of the x-ray beam
Appears black or radiolucent
More x-rays reach the film, more silver halide crystals are energized
Radiopaque
Resists passage of the x-ray beam
Appears white or radiopaque
No x-rays reach the film because they are absorbed by dense structures, no crystals are energized, film is unexposed
Film Processing Steps
Development (creates radiolucent areas)
Reduces crystals into black metallic silver
Rinsing
Removes developer to stop the developing process
Fixation (creates radiopaque areas)
Removes "clears" unexposed crystals from the films emulsion
Washing
Removes all excess chemicals
Drying
Dries for film handling
Development
To reduce the exposed, energized silver halide crystals into black, metallic silver
Softens the film emulsion
Rinsing
Stops the development process
Washing
Removes all excess chemicals from the emulsion
Drying
Films must be dried before they can be handled for mounting or viewing
Film Processing Solutions
May be obtained as
Powder
Ready-to-use liquid
Liquid concentrate
To maintain freshness
-Must be replenished daily
-Changed every 3 to 4 weeks
-May need to change more frequently when large numbers of films are processed
4 Developer Solution Components
1. Developing agent (decreases oxidation)
Hydroquinone: black tones and sharp contrast
Elon: shades of gray
2. Preservative (prolongs life span)
sodium sulfite
3. Accelerator (activates developing agents)
sodium carbonate
4. Restrainer (slows down action of the chemicals)
potassium bromide
4 Components of Fixer Solution
1. Fixing agent (clears the film so black image can be seen)
Sodium thiosulfate or ammonium thiosulfate
Commonly called "hypo"
2. Preservative (prevents chemical breakdown of fixing agent)
sodium sulfite
3. Hardening agent (hardens and shrinks the emulsion)
potassium alum
4. Acidifier - acetic acid or sulfuric acid
Darkroom
A completely darkened environment within which x-ray film can be handled and processed to produce diagnostic radiographs
Must be properly designed and equipped
Room requirements
Conveniently located
Adequate size
Equipped with correct lighting (safe light)
Arranged with ample work space with adequate storage
Temperature and humidity controlled
Location and size
Should be near where x-ray units are installed
Large enough to
Accommodate film processing equipment
Allow ample work space
Size is determined by
Volume of radiographs
Number of persons
Type of processing equipment
Space required for duplication of films
Storage
Lighting
Light-tight
No light leaks can be present
Light leak
Any white light that "leaks" into the darkroom
Room lighting
Required for procedures not associated with processing films
Safelighting
Composed of long wavelengths in the red-orange portion of the visible light spectrum
Safe lighting
A lamp with a low-wattage bulb (7½ or 15 watts)
Safelight filter
Removes short wavelengths in the blue-green portion of the visible light spectrum
A safelight should be placed a minimum of 4 feet away from the film and working area
Dark room work space
Must include an adequate counter area where films can be unwrapped
Must be kept clean, dry, and free from processing chemicals
Dark room storage space
Humidity level
dark room plumbing
equipment requirements
Processing tank
Automatic processor
Processing Tank
Manual processing
-Hand processing

Processing tank
-Divided into compartments to hold developer solution, water bath, and fixer solution

Insert tanks
-Two tanks to hold developer and fixer solutions
-Both fit into master tank

Master tank
-Suspends both insert tanks
-Filled with circulating water

Mixing valve
-Controls the water temperature
Automatic processor
Automates all film-processing steps
-May be limited to certain sizes of films
-May require a darkroom

Daylight loader
-May be used in a room with white light
Manual film processing
Equipment accessories
Step-by-step procedures
Care and maintenance
Equipment Accessories
Thermometer
- placed in developer solution

Timer
- to indicate processing time intervals

Film hangers

Miscellaneous equipment
-stirring rod
Step-by-step procedures
Determine which solution is the developer
Check solution levels
Stir the solutions
Check temperature of developer solution
Label film hanger with name of patient and date of exposure
Close and lock darkroom door, turn off white lights, and turn on safelighting
Unwrap each exposed intraoral film over a clean working surface
Clip each film to the labeled film hanger
Set the timer
Immerse the films into the developer solution and agitate
Remove films from developer and place in circulating water
Determine fixation time and set the timer
Immerse the films in fixer solution and agitate
Remove films from fixer and place in circulating water
Remove films from circulating water
Air dry the films or use a drying cabinet
Remove the radiographs from the film hanger
Examine the radiographs and place them in a film mount
Clean processing equipment and work surfaces
Care and maintenance
Processing solutions
Processing tank
Miscellaneous equipment
Processing Solutions
Follow manufacturer's instructions for storage, mixing, and use

Solutions deteriorate with
-Exposure to air
-Continued use
-Chemical contamination

Developer solution
-Depleted from evaporation and removal of small amounts
-Exhausted developer does not fully develop the latent image

Fixer solution
-Depleted from evaporation and removal of small amounts
-Diluted each time water is transferred from rinse
-Exhausted fixer does not stop the chemical reaction sufficiently

Replenisher solution
-both developer and fixer must be replenished daily

Replenisher
-superconcentrated solution

Oxidation
-The process that occurs when developer and fixer combine with oxygen and lose strength
Processing tank
Mineral salts in water and carbonate in processing solutions produce deposits on the inside walls of the insert tanks

Tanks must be cleaned with commercial cleaner or hydrochloric acid when the solutions are changed
Miscellaneous equipment
Film hangers
Stirring paddles
Plastic apron
Automatic film processing
Often preferred over manual film processing
-Less processing time required
-Time and temperature automatically controlled
-Less equipment used
-Less space required
Component parts of Automatic processor
-Uses a roller transport system to move dental x-ray film through developer, fixer, water, and drying compartments
-Processor housing
-Film feed slot
-Roller film transporter
-Developer compartment
-Fixer compartment
-Water compartment
-Drying chamber
-Replenisher pump and replenisher solutions
-Film recovery slot
Automatic film processing step-by-step
Prepare darkroom
Prepare films
Insert each unwrapped film into the film feed slot of the processor
Retrieve the processed radiographs
Automatic film care and maintenance
Automatic processor
Processing solutions
Automatic processor
Requires routine preventive maintenance
-A cleaning and replenishment schedule must be established
-May require daily or weekly cleaning

Cleaning film
-Used to clean the rollers of an automatic processor
Processing solutions
Levels must be checked at the beginning of each day and replenished as necessary
Film Duplication equipment requirements
Film duplicator
-A commercially available light source

Duplicating film
Film Duplication step-by-step
-Arrange radiographs
-Place duplicating film on top of the arranged radiographs emulsion side down
-Secure duplicator lid
-Select exposure time and activate light source
-Process the duplicating film
-Label the processed duplicate radiographs
Time and Temperature
Underdeveloped film
Overdeveloped film
Reticulation of emulsion
underdeveloped film
Appears light
-Inadequate development time
-Inaccurate timer or thermometer
-Low developer temperature
-Depleted or contaminated developer solution

Solution (To prevent underdeveloped films)
-Assess areas listed
Overdeveloped film
Appears dark
-Excess development time
-Inaccurate timer or thermometer
-High developer temperature
-Concentrated (overactive) developer solution

Solution (To prevent overdeveloped film)
-Assess areas listed and make adjustments, decrease temperature, replace solution etc.
Reticulation of Emulsion
Appears cracked
-Results when a film is subjected to a sudden temperature change between the developer and the water bath

Solution (To prevent Reticulation of Emulsion)
-Avoid drastic temperature differences
-Check temperatures carefully
Chemical Contamination
Developer spots
Fixer spots
Yellow-brown stains
Developer spots
Appears as dark spots on the film
-Seen when developer solution comes in contact with the film before processing

Solution
-Use a clean work area
-Place films on a paper towel in work area prior to unwrapping
Fixer spots
Appears as white spots on the film
-The result of fixer solution coming in contact with the film before processing

Solution
-Use a clean work area
-Place films on a paper towel in work area prior to unwrapping
Yellow-Brown Stains
Film appears yellow-brown
-Use of exhausted developer or fixer
-Insufficient fixation or rinsing

Solution
-Replace depleted developer and fixer
-Allow adequate fixing and rinsing time
Film Handling
Developer cut-off
Fixer cut-off
Overlapped films
Air bubbles
Developer cut-off
Appears a a straight white border on the film
-Results from a low level of developer solution

Solution
-Check developer level
-Replenish as necessary
-Make sure films are completely immersed
Fixer cut-off
Appears as a straight black border on the film
-Results from a low level of fixer solution and and unfixed portion of the film is represented

Solution
-Check fixer level
-Replenish as necessary
-Make sure films are completely immersed
Overlapped films
Appears as white or dark areas on film where overlapping has occurred
-Two films coming in contact during processing
-Overlapped in developer=white lines
-Overlapped in fixer=dark lines

Solution
-Be certain to carefully process films to avoid contact between two films
Air bubbles
Appear as white spots on the film
-Seen when air is trapped on the film surface after the film is placed the the processing solutions
--Air prevents the chemicals from affecting the emulsion

Solution
-Gently agitate and stir film racks after placing tem in the processing solution
Film handling
Fingernail artifact
Fingerprint artifact
Static electricity
Scratched film
Fingernail artifact
Appears as a black crescent-shaped mark
-Film emulsion is damaged by the operators fingernail during rough handling

Solution
-Gently handle film
-Keep nails short
Fingerprint Artifact
Appears as a black fingerprint on the film
-Seen when the film is touched by fingers contaminated with fluoride or developer

Solution
-Wash and dry hand thoroughly before processing
-Work in a clean area
-Handle the films by the edges
Static Electricity
Appears as thin black branching lines on the film
-Opening film packet quickly
-Occurs frequently during periods of low humidity

Solution
-Open film packet slowly
-In a carpeted office, touch a conductive object before unwrapping film
Scratched film
Appears to have white lines on the film
-When the soft film emulsion is removed from the film base by a sharp object such as a film clip or hanger

Solution
-Use care when placing film on a rack and avoid contact with other film hangers
Lighting
Light leak
Fogged film
Light leak
Appears black in exposed area
-Accidental exposure of the film to white light
-Torn or defective packets that expose a portion of the film

Solution
-Examine film packets for tears
-Never unwrap film in the presence of white light
Fogged film
Appears gray and lacks image detail and contrast
-Improper safelighting and light leaks in darkroom
-Improper film storage
-Outdated film
-Contaminated solutions
-High developer temperature

Solution
-Check safelight filter and wattage of bulb
-Check expiration date of film
-Check temperatures
-Avoid contamination of solutions
At 68 degrees F, the optimal development time is:
A. 2 minutes
B. 3 minutes
C. 4 minutes
D. 5 minutes
D. 5 minutes
A breakdown of chemicals in the processing solution that results from exposure to air is termed:
A. Reduction
B. Selective reduction
C. Oxidation
D. Replenishment
C. Oxidation
The film emulsion is hardened during:
A. Development
B. Rinsing
C. Fixation
D. washing
C. Fixation
Hydroquinone brings out _____ tones, whereas Elon brings out _____ tones.
A. Black/white
B. White/black
C. White/gray
D. Black/gray
D. Black/gray
In manual processing the thermometer should be placed in the:
A. Developer
B. Water
C. Fixer
D. Either a or b
A. Developer
because developer temp is so critical
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