Processing Radiographic Film Flashcards
What is the term for data in unprocessed film?
The latent image
What is the site where electrons are trapped thereby producing the latent image and what are these made of?
Sensitivity sites, made of silver bromide crystals and sulfur
What types of interactions cause the removal of an electron from the bromide in the emulsion?
Compton and photoelectric
The bromide is converted into what upon losing an electron?
Bromine
Once an electron is removed from bromide it moves to the?
Sensitivity site
With the electron embedded in the sensitivity site it is now negatively charged, what binds to it?
Silver ions which are positive
With the silver ions in the sensitivity site, this creates an area of dark or light after processing?
Dark or radiolucencies
How does developer work?
Converts latent image sites to grain of solid silver by reducing the silver ions to silver grains, therefore DOES NOT WORK ON UNEXPOSED SITES
What is the purpose of fixer?
Removes unexposed silver bromide creating clear areas or radiopacities
What are the 5 steps of film processing?
- Immersed in developer
- Rinsed in water bath
- Immersed in fixer
- Washed in water bath
- Dried
Which step is skipped in automated processing?
Rinsing in a water bath following developer
What are the 4 components of developing solution?
- Activator
- Preservative
- Restrainer
- Developer
What are the two components of developer?
Phenidone and hydroquinone
What is the purpose of activator?
Raises the pH of developer to about 10 since its only active at an alkaline pH
What is the purpose of preservative?
Prevent oxidation of the developer and extend its useful life
What is the preservative made of?
Sodium sulfite
What is restrainer made of?
Potassium bromide and benzotriazole
What is restrainer used for?
Prevent development of unexposed silver bromide crystals, prevents fogging
Why do we rinse the film with water after using developer?
Drops pH and stops developer activity and prevents deactivation of the fixer which is acidic
What can happen to the film if fixer is not used?
The film is dark and non-diagnostic
What are the 4 components of fixer?
Clearing agent
Acidifier
Preservative
Hardener
The clearing agent contains what? What is its purpose?
Ammonium thiosulfate
Clears unexposed silver halide
Acidifier is made of what acid? What are its purposes?
Acetic acid
Maintains a constant acidic pH and inactivates any remaining developing solution
What is the hardening agent made of and what is its purpose?
Aluminum sulfate which combines with gelatin to make the emulsion less prone to damage from handling
If thiosulfate and silver thiosulfate are left in the emulsion, what will be seen on the radiographs?
Brown stains
How long can a film be exposed to a safelight?
5 minutes
A safe light can be how many watts and how far from the film?
15 watts and a minimum of 4 feet from the film
The type of filter used in a safelight is?
Red GBX-2
What are the 3 components of a processing tank from left to right?
Developer, water bath, fixer
When film is placed on the drying rack, a fan should be pointed?
Nearby but not directly at the film to hasten drying
In the developing and rinsing step of manual processing we?
- Put the film into developing solution and alginate to dislodge air bubbles
- Remove the film shortly after its finished
- Rinse or alginate the film for 30 seconds
What is the next step after developing and rinsing?
Fix and wash, alginate the film for 5 seconds every 30 seconds
How long are films fixed and then rinsed for?
Fixed for twice the developing time and rinsed for three times the developing time
If you develop at higher temperatures does it take more or less time?
Less time
What is the drawback to developing at higher than normal temperatures?
Increasingly grainy images
How long does automated processing take?
4.5 to 8 minutes
What is a daylight loader?
Miniature darkroom that allows films to be unwrapped under safelight conditions
What does the roller transport do?
Carries unwrapped film from one section of the automated processor to the next
The squeegee action of the roller may?
Increase the energy of the developer, boosting film speed from E to F speed
Since the roller transport effectively speeds up film, what does this mean in terms of exposure?
We can lower it and get the same film quality
What are downsides to automated processors?
Grainy images due to higher temperatures
Roller marks
Mechanical breakdowns
Meticulous care of processors
