Radiographic Film PP Flashcards
What were the 1st images recorded on?
Glass
What type of film’s base was highly flammable?
Cellulose Nitrate
What is now the film base of choice?
Polyester
What is Remnant radiation?
Anything radiographically leaving the patient after attenuation interacting with the image receptor
What is another name for Remnant Radiation?
Exit Radiation
What are the image forming x-rays?
Remnant Radiation
How much energy deposited is from visible light?
99%
What happens when x-rays strike the intensifying screen?
x-ray energy is converted to visible light
What colors are film typically tinted?
Pale blue or blue-gray
to prevent eye strain
What are (3) components every film must have?
Must be:
- Clear
- Strong
- Consistent
What side of the base can a photographic emulsion be on?
Can be on one side or both.
single or double emulsion
Why is there a protective overcoat layer on top of emulsion?
To prevent from scratching off image
What does the emulsion layer do?
Stores the image
What are the parts that construct the film?
Supercoat Emulsion Adhesive Base Adhesive Emulsion Supercoat
What are some characteristics of the Base?
- Transparent
- Uniform thickness & color
- Impermeable in water
- Non-flammable
What is the function of the film base?
- Support for emulsion layer
- Transmit light to view image
What is the emulsion later made of?
Gelatin
What does gelatin do for the emulsion layer?
Provides mechanical support
What is the function of the emulsion layer?
- Heart of the x-ray
- Stores the latent image
What is the latent image?
Unseen image until processed
After processing, what does the latent image become?
Manifest image
Where does the formation of the latent image begin?
At the sensitivity specks
What is the Gurney-Mott Theory?
- Incident photon interacts with a silver halide
- Ejected electron is freed, may be attracted and trapped by sensitivity speck, giving it a (-) charge
- The (-) charged speck attracts a free silver ion
What are the (5) types of film?
- Screen Film
- Direct Exposure Film
- Filmless Cassettes (RT-TAG Chip)
- Special Application Film
- Direct Digital
Which type of film has no filtering?
Direct Exposure
Which film will give you greater detail, but more patient dose?
Direct Exposure
What causes the grays and blacks on your film?
Where the Silver Halide crystals pop up
What determines how dark the Silver Halide crystals are?
Size
Shape
Distribution
What is resolution?
Detail
What kind of film would you choose to get high resolution?
A Thin emulsion layer with a small crystal size
An image that has high contrast is formed by…
Black and whites
An image that has low contrast is formed by what?
Scales of grey
The contrast of an IR is ________ _________ to it’s exposure latitude.
Inversely proportional
If an image has a narrow latitude, it has a…
High contrast
If an image has a wide latitude, it has a…
Low contrast
What determines the latitude of an image?
The size and distribution of the silver crystals
What is a ghost image?
A retained image, that has not been erased
How does film grain happen?
With improper:
- Exposure factors
- Magnification
- Casting
- Improper protocol
What is film speed dependent on?
- Sensitivity to x-rays and light
- Type of crystals
- Covering Power
What is Covering Power?
The more efficient use of silver in the emulsion with less dose
Current emulsions contain less silver, yet produce the same optical density per unit exposed. What is this called?
Covering Power
What is the highest user of silver in the world?
Medical Imaging
What is film latitude?
The range of exposure
*Wide vs. Narrow Latitude
What is recorded detail?
- High Resolution
- Sharpness
- It is inverse to film speed
Can you have visibility without detail?
Yes
What does crossover light cause?
Increased blurring on the image
How does Screen Film Crossover happen?
Light is emitted from intensifying screen, exposing the adjacent emulsion
What does the crossover layer do?
- Absorbs most of the crossover light
- Does not diffuse into the emulsion, but remains a separate layer
- Completely removed during processing
What can reduce or eliminate crossover?
The use of intensifying screens
Why are films tinted different colors?
To reduce user fatigue
A blue based film will emit what color glow when irradiated?
Blue
What is the Reciprocity Law?
- We can use different techniques and get the same optical density
- You can use different mA and time as long as they equal the same mAs
What filters are used with both green and blue sensitive film?
Red Filters
What colored films are Amber filters use for?
Blue sensitive films
What watt bulb should be used in the dark room?
15 watt
How close should the bulb be from the work surface?
No closer than 5ft
What are direct exposure films used for?
Higher detail
How much does Direct Exposure Films increase patient dose?
10-100 times
When was Direct Exposure used?
In Mammography until the early 1970’s
Describe Direct Exposure Films:
- Thick emulsion
- Less sensitive to light
- Cardboard cassette
- Higher detail
What kind of film was used by mammography?
- Single emulsion
- Single intensifying screen
What does C.A.D stand for?
Computer Aided Detection
What type of dedicated film reduces cross-over and contains special dyes to reduce reflected light
Mammography Film
What are the two types of laser film?
Wet & Dry
What type of laser film has to go through a processor and needs a dark room?
Wet Film
What type of laser film comes right out of the printer?
Dry Film
What type of film allows for a greater tolerance for over and under exposure?
Filmless Cassettes
What is an RF-TAG chip?
Allows patient demographics and examination date to be entered and linked to the image
What are some considerations for film storage?
- Temperature
- Humidity
- Light
- Radiation
- Shelf Life
- Storage Position
- Handling
What is the #1 Error when handling and storage of film?
Exposing the film bin
What can result from improper handling of film?
- Poor Radiographs
- Improper processor maintenance
- Artifacts
- Rough Handling
- Sharp Objects
- Lotion
- Creasing/ Bending
What does heat and humidity result in?
A loss in contrast
What is the optimal storage for film?
Cool dry place @ 50°
Test
How do you get longer life out of your film?
By putting it in the refrigerator
Where must film be stored and handled?
In the dark
What would happen if bright light exposes or partially exposes film?
Artifacts are produced
Are films sensitive to radiation?
Yes
What is film fog?
Unintended optical density that reduces contrast
How do you store film?
On edge and rotate
What happens if you store films flat?
They stick together
What is the average storage time of film?
45 days
How long are mammo films kept?
For the life of the patient
How long are pediatric films kept?
Until they are adults
How long are radiographic films kept?
5-7 years depending on the state. Typically 7 years.
