Processing the Image Flashcards
The five components of processing:
Transport System Replenishment System Recirculation Temperature Control Drying
The transport system is designed to:
move film through the developer, fixer, wash and dryer sections of processor
What happens to the film in the transport system?
Film is submerged & agitated in different solutions during a set amount of time
The transport system consists of:
Transport racks
Crossover networks
Drive system
The tanks of the automatic processor contain _______ and are stainless steel in order to ___________.
Developer, fixer and washer. Prevent corrosion.
What is the feed tray and what are three things it does?
The feed tray is a flat metal surface edged on both sides, which allows for correct alignment of the film, it feeds films evenly to maintain correct replenishment rate, and it alternates film from side to side to ensure proper wear of rollers.
The entrance roller assembly is made up of:
rollers covered in corrugated rubber.
The purpose of the entrance roller assembly is:
to keep film in a straight path.
What could possibly happen if films overlap?
The system could jam, causing inadequate processing of both films.
What do transport rollers do and how are they situated?
They move film through the chemical tanks and dryer assembly. Some are positioned parallel and some are staggered.
A turnaround assembly (deep in tanks) consist of:
Master roller, planetary roller, guide shoe.
The turnaround roller (master roller) is found where, and what does it do?
At the bottom of the roller assembly and it turns film from moving down to moving up.
Describe planetary rollers.
The are positioned on either side of the master roller to aid in proper alignment of the film.
Describe guide shoes (plates).
They are curved metal plates positioned on either side of the master roller that guide film through the assembly.
Where are crossover rollers found and what do they do?
They are found at the top of the assembly, between tanks, and they move film from one tank to another and finally into the dryer.
Why is the space between crossover rollers very tight?
To give a “squeegee” effect on the film and remove excess liquid to avoid contamination of chemicals.
Why are most rollers positioned on a rack assembly?
To make it easy to remove and clean the rollers.
How is the drive system powered?
By a single electric motor.
The drive system consists of:
a series of mechanical devices which turn all the rollers in the processor.
The speed of the drive system is set to:
45-90 seconds from entrance roller to receiving bin.
Describe “standby control” of the drive system.
electric circuit shuts off power when processor not in use. This improves cost effectiveness, reduces wear and tear on assembly, and decreases water use.
Why do chemicals need to be replenished and which chemicals need replenishing?
Chemicals eventually become exhausted. The developer and fixer need replenishing.
How is film placed in the feed try to ensure proper replenishing?
Horizontal, with the short side against the feed tray guide.
What does over-replenishment of developer cause?
Increased density and decrease in contrast.
What does over-replenishment of fixer cause?
It does not affect image but is a waste of solution.
Under-replenishment of the developer AND fixer causes:
film to jam in roller due to inadequate hardening of film emulsion.
Under-replenishment of developer causes:
decreased density.
Under-replenishment of fixer causes:
poor archival quality (brown stains.).
Two ways to replenish chemicals are:
Volume replacement and flood replacement.
Volume replacement of chemicals is used for:
High volume workload.
How is volume replacement of chemicals achieved?
Micro-switch activated - turns on replenishment and remains on as long as film is traveling through
Flood replenishment is done when?
At timed intervals.
Flood replenishment is useful for:
processors that utilize low to medium number of films.
What does the re-circulation system do?
Circulates the solutions in each tank by pumping solution out of one portion of tank and returning it to different location in same tank. Also helps stabilize temperature.
What does the re-circulation filter do?
removes impurities as developer solution is re-circulated.
Pieces of gelatin from emulsion become dislodged and can attach to rollers causing artifacts.
How does an increase in temperature of the developer affect the image?
Increases density.
How does a decrease in temperature of the developer affect the image?
decrease in density
What are the two types of temperature control?
Immersion heater and heat exchanger.
How does an immersion heater work?
heating coil immersed in bottom of tank.
Brings in cold water and heater warms up water
Which type of temperature control is more common?
Heat exchanger.
What does a heat exchanger use to heat the developer?
A thermostat. The developer solution is routed through circulation coil in bottom of fixer tank and fixer is heated by conduction
Temperature is monitored at each stage of processing by
a thermostat device.
What temperature is the developer kept at?
33-35 degrees C (92-96 degrees F)
What temperature is the wash water kept at?
3 degrees C (5 degrees F) lower than the developer temperature.
Why are films dried?
Films not properly dried will pick up dust & particles which could create artifacts
How are films dried?
Hot air blown onto both sides of film (by air tubes) as moves through dryer
Temperature of air thermostatically monitored to control
Moisture removal.
What does the drying system consist of?
Squeegee rollers, double row of forced hot air tubes, and high speed fans that produce air at 120 - 150 degrees F.
What happens to the emulsion as it dries?
It shrinks and seals.
When films come out damp, its usually due to:
lack of hardener in fixer or water saturated with chemicals – not due to the dryer
What is an artifact?
Any unwanted image on a radiograph.
What are the unwanted characteristics that an artifact will add to a radiograph?
Can decrease visibility of anatomy
Hide a pathological condition
Cover up patient identification information
Decrease overall radiographic quality
An artifact can be considered _____ or ______ density.
plus, minus.
A plus density artifact is:
greater in density than area of radiograph immediately surrounding them
A minus density artifact is:
less density than area of radiograph immediately surrounding them.
Plus density scratch artifacts can be caused by
a fingernail.
A minus density artifact can be caused by:
moisture on the finger.
Artifacts can be classified as either:
Exposure Artifacts
Processing Artifacts
Handling & Storage Artifacts
Exposure artifacts are associated with
the manner in which the radiographer performs exam.
A few examples of exposure artifacts:
Motion
Improper pt position
Wrong screen-film match
Processing artifacts are
produced during processing
Most processing artifacts are _______ caused by:
pressure-type, transport system which appear as higher optical density. When emulsion is scraped or removed they appear as lower OD.
Different types of processing artifacts:
Emulsion pickoff & Gelatin buildup
Curtain effect
Chemical fog
Emulsion pickoff & Gelatin buildup
Caused by dirty or warped rollers
Deposits sludge on film
Curtain effect
Excess chemistry runs down edge of film
Chemical fog
Caused by improper or inadequate processing chemistry
Guide shoe marks
Caused by improper or inadequate processing chemistry
They have low optical density.
Pi lines
Occur at 3.1416 inch intervals (one revolution of roller)
Caused by dirt or chemical stain on roller which affects the emulsion
Wet pressure sensitization:
Caused by irregular or dirty rollers
Dichroic stain
chemical stain caused by improper or inadequate processing chemistry
Dichroic means:
two colors, however they can appear as yellow, green, blue, or purple
Dichroic stain can appear as a curtain effect, but is also used as
a general term for all chemical stains
Examples of handling artifacts:
Scratches, pressure marks, tree static, & smudge static.
Long storage time with hypo retention from fixer results in
yellow-brown stains. This occurs when there is residual thiosulfate on the film (not properly washed off) and silver sulfide slowly builds up and appears yellow in stored radiograph.
Debris on IR in DR can be confused as
a foreign body.
Plus-density half-moon artifacts can be caused by
bending or kinking the film.
Dirty screens or cassettes can cause
nonspecific minus density artifacts
An unintended foreign object on the radiograph results in
a minus-density artifact
Minus-density scratch artifacts can be caused by
transport rollers
Plus-density static discharge artifact can be caused by
sliding a film over a flat surface
What makes silver recovery possible?
Fixer - removes unexposed silver halide from film therefore contains high concentration of silver
Disposing of silver regulated by
state and local agencies.
How is silver recovered from X-ray departments with low volume?
Silver is drained into holding tank
Periodically picked up by silver recycler
How is silver recovered from departments with high volume?
Recovery units connected to drain system of fixer tank
Metallic Replacement
Electrolytic Method
Processor Quality Control (What steps are taken?):
Periodic cleaning(weekly) System maintenance (monthly) Daily monitoring (temp recorded daily with sensitometric strip)
Why must the processor be cleaned?
high temperatures & concentrated chemistry put wear on processor
What is an alternative processing method?
Daylight processing.
What is daylight processing and what are its benefits?
film automatically extracted, processed and cassette reloaded
No need for darkroom
Ease of use
Speed
What is Material safety data sheet (MSDS)
Explain what to do if chemical exposure
Should be aware of where it is in your department
How can one protect themselves from Darkroom chemical sensitivity
When handling chemicals gloves & goggles should be worn
What is OSHA?
The Environmental Protection Agency & Department of Transportation have all implemented regulations affecting processing chemicals. (1986)
MSDS required of
anyone using chemicals.
Why is preventative maintenance necessary?
to keep system performing at optimum level
