8.2 Film Processing 2 Flashcards
• Special curved plates made of either plastic or metal are
positioned at the sides and bottom of the master roller
and are called
guide shoes
support the transport rollers and
turnaround assemblies
Transport Racks
can be removed for cleaning or maintenance
Transport Racks
After the film travels to the top of the transport rack, it
passes between _____ rollers that remove excess
chemicals or water before the film enters the next tank
squeegee
An electric motor and a system of gears,
chains, sprockets, belts and pulleys provide mechanical
power and motion in the transport system
Drive Motor
Any _____ of the components or change in the speed
of the motor causes improper film processing and poor
image quality
slippage
Proper ____ temperature is
required to properly convert the latent image to a manifest image
developer
Variations of greater than _____ from
the temperature recommended by the film
manufacturer will result in a manifest image that either
has too much or too little density
±5 degrees Fahrenheit
controlled by recirculation pumps that
agitate the processing solutions to keep them mixed, to
maintain constant temperature throughout the solutions and to
assist the exposure of the film’s emulsion to the processing
chemicals or water as it passes through the developer, fixer and
wash tanks
Recirculation System
The dryer system consists of:
blower, ventilation ducts, vented
dryer tubes and an exhaust system
draws in room air and passes it over heating coils. The heated air then enters the ventilation ducts and dryer
tubes, and then blows over the surface of the film emerging
from the wash tank
blower
are made of plastic and are hollow.
Small slots that face the film as it travels down and up
through the dryer section are cut into the tubes
dryer tubes
the processor contains electrical
circuits that power its drive motors and temperature
control system
Electrical System
can be defined as the amount of
time required for the leading edge of the film to enter
and the trailing edge of the film to exit the processor
PROCESSING RATE
PROCESSING RATE e is commonly called the
drop time
The total processing rate should not vary more than ____ of the
time specified by the manufacturer
± 2%
Conventional general-purpose automatic processor used
in medical imaging departments today process a
radiographic film in approximately ___
90 seconds
enables film
processing without the need for a conventional
darkroom
DAYLIGHT AUTOMATIC PROCESSORS
that are compatible with the daylight system are used
Special daylight cassettes
DAYLIGHT AUTOMATIC PROCESSOR
1.) Unexposed films or various sizes are stored in a loading
dispenser located within the daylight processor unit.
2.) The cassette is inserted into the processing unit where
the exposed film is automatically removed and a new film
is loaded into the cassette.
3.) The exposed film is transported to the processor
The main advantage of a ______ is increased
departmental efficiency
daylight system
Other advantages: daylight system elimination of the need for a darkroom or trained darkroom personnel
daylight system
• Disadvantages: Mechanical failure and artifacts cause
by mechanical components of the film transport system
daylight system
Another disadvantage: Cost
daylight system
is important to prevent particulate
matter from producing artifacts on processed films
Routine cleaning
is often realized as a decrease in
radiographic image quality
Processor malfunction
Other indications of processor malfunctions are:
-Film jamming
-Audible cheering of the transport rack system or drive motor
subsystem
-Electrical power failure
Factors Causing Excessive Image Density
- Developer temperature too high
- Developer overreplenishment
- Developer contaminated with fixer
- Processor running too slow
- Developer improperly mixed
- Processor light leak
Factors causing Insufficient Image Density
- Developer temperature too low
- Developer underreplenishment; exhausted developer
- Processor running too fast
- Developer improperly mixed
is an unwanted, irregular density or mark
seen on a radiograph
Artifact
Artifacts Running Parallel to Film Travel Through
Automatic Processor
- ) Guide Shoe Marks
2. ) Entrance Roller Marks
Possible Radiographic Appearance (PRA): Evenly spaced plus-density lines
Cause: Excessive pressure
from misaligned guide shoes
Guide Shoe Marks
obvious density lines
Plus-density lines
not obvious density lines
Minus-density lines
Possible Radiographic Appearance (PRA): Evenly spaced minus-density lines
Cause(s): Misalignment of guide shoes; emulsion scratched
off base
Guide Shoe Marks
Possible Radiographic Appearance (PRA): Plus-density lines
Cause(s): Excessive pressure from entrance rollers or
moisture on entrance rollers
Entrance Roller Marks
Artifacts Running Perpendicular to Film travel Through
Automatic Processor
- Hesitation Marks
- Chatter Marks
- Pi Lines
Possible Radiographic Appearance (PRA): Plus-density lines(s) usually seen near leading edge
of film
Cause(s): Malfunctioning gears or loose chain; warped
rollers
Hesitation Marks
Possible Radiographic Appearance (PRA): Plus-density lines evenly spaced
Cause(s): Loose drive gears, chain or developer-to-fixer crossover
rack assembly
Chatter Marks
Possible Radiographic Appearance (PRA): Plus-density lines spaced 3.14 inches apart
Cause(s): Dirty rollers, emulsion build-up on rollers; developer
solution level too low causing incomplete immersion of top rollers
of transport roller rack assembly
Pi Lines
Random Processing Artifacts
- Water Spots
- Pick-Off
- Brown Tint
PRA: Dull, superficial and irregular spots or streaks seen best
with reflected light
Cause: Malfunctioning squeegee rollers from wash tank, clogged
dryer tube(s)
Water Spots
PRA: Small, randomly spaced minus-density spots
Cause(s): Rough or dirty rollers lifting small pieces of emulsion off
base
Pick-Off
PRA: Emulsion has brown appearance
Cause: Inadequate film washing
Brown Tint
Film Handling Artifacts
- Scratches
2. Static Marks
PRA: Linear minus-density marks
Cause(s): Dropping film on the floor; sliding film on dirty feed
tray; careless insertion of film in film bin or during cassette
loading
Scratches
PRA: Plus-density marks that may appear randomly across the
film (3 common types are smudge, crown and tree static)
Causes(s): Low humidity; inadequate grounding of workbench;
careless handling of film such as rapidly removing film from
cassette or film bin
Static Marks
Unexposed and Undeveloped Silver Halide Crystals are
removed by the ___ solution
fixer
Silver Recovery by _____ is achieved by passing an
electrical current through two electrodes that are
submerged in a bucket that received the used fixer
solution
electrolysis
• 1 electrode is positively charged (anode) and the other
electrode is negatively charged (cathode).
• The cathode will attract the silver (positively charged)
and the cathode becomes silver-plated
Electrolytic Recovery
When the electrical current is turned off, the silver is scraped off the ____ and sold
cathode
One advantage: desilvered fixer can be recirculated for
repeated use
SILVER RECOVERY
There are 2 methods of chemical silver recovery:
- ) Metallic placement
2. ) Precipitation Method
involves passing silver-bearing
fixer solution into a bucket containing steel wool
Metallic placement
• The fixer solution causes the steel wool to give up electrons to
the positively charged silver ions to form metallic silver.
• The metallic silver either attaches to the steel wool or settles to
the bottom of the bucket in the form of sludge
Metallic placement
fixer solution is precipitated as
silver sulfide by adding sodium sulfide to the solution
Precipitation Method
The chemical reaction between sodium sulfide and silver
bromide produces silver sulfide, which _____ out of
solution
precipitates
• Although this method of silver recovery is very efficient,
toxic fumes are produced
Precipitation Method
Because toxic fumes are produced, and the fact that silver
sulfide sludge is difficult to handle and dry, this method of
silver recovery is rarely used in medical imaging
departments
Precipitation Method
