Film Flashcards
What type of film remains the least common radiographic image receptor used today?
Photosensitive film
Manufacturing of radiographic film has to be very precise and high quality procedure in order to prevent what on the radiographic image?
Artifacts (unwanted objects on film)
What are the 4 layers of the radiographic film construction?
- Base
- Adhesive Layer
- Emulsion
- Supercoat (overcoat - protective layer)
- What does the base do?
- What is the base made out of (4)?
- The base provides a structure for the emulsion layer
Made out of:
- Glass (What Roentgen used)
- Cellulose Nitrate (very flammable and caused hospital fires)
- Cellulose Triacetate (non-flammable but expensive)
- Polyester (still used today)
What must the foundation of the radiographic film be?
- Flexible
- Uniformly radiolucent
- Durable
Film must retain its size and shape from…
- Radiation exposure
- Wet chemical processing
Thickness of the foundation of the radiographic film ranges from ___ - ___ micrometers.
Thickness of the foundation of the radiographic film ranges from 150-200 micrometers.
Why is the film base usually tinted?
What color is it tinted?
To reduce eye strain for the radiologist while reading the film
Tinted blue
The film base is also covered with a special substance to prevent what?
What is this called?
Light from one screen crossing over to the other
“Crossover effect”
The adhesive layer is a ___ coating of the “___” that is applied to the base to hold the ___ (active) layer on the base.
The adhesive layer is a thin coating of the “glue” that is applied to the base to hold the emulsion (active) layer on the base.
The emulsion layer responds to what 2 things that strike it?
Light or radiation
The emulsion layer is also called the “heart of the film”.
What are the 2 parts of the emulsion layer?
Gelatin and silver halide crystals
What does gelatin do (in the emulsion layer)?
Supports the crystals and distributes crystals evenly on film
What are silver halide crystals (emulsion layer)?
What is it made up of (%)?
Active ingredients of the emulsion layer
made up of:
- silver bromide - 95-98%
- silver iodine - less than 5%
- silver chloride
What does it mean when a film is a double emulsion film or duplitized film?
Emulsion layer on both sides of the base
What type of film gave the best detail?
What modems used it?
Single emulsion film
Mammography, CT, MRI
Describe the dull and shiny side on a single emulsion film?
Dull = emulsion side
Shiny = base side
What layer of the film is the protective layer/protects all the other layers in a wet or dry stage?
Supercoat
What does the supercoat layer prevent during film processing or handling of the film?
What is added to prevent static artifacts on the film?
Prevents scratches and abrasions
Antistatic agent
What are the 4 steps to manufacture the radiographic film?
Where must it take place?
- Crystal Production
- Ripening
- Mixing
- Coating
Must take place in total darkness
Silver bromide crystals production is performed in total darkness.
What combination forms silver bromide crystals?
Silver nitrate and potassium bromide mixed with gelatin
Crystal Classification and Shapes
Silver halide crystals are ___% silver bromide and ___% silver iodide
What are tabular shape used most commonly for?
What are the advantages of tabular shape (CAS)?
- Silver halide crystals are 98% silver bromide and 2% silver iodide
- General radiography
Advantages:
- Can use thinner emulsion (flat-triangular)
- Absorbs more photons
- Speed up processing
Silver Halide Crystal Structure
- Resulting shape can be…
- However, the inner structure takes on a ___ form or cubic lattice
- Each ___ or ___ is a cubic lattice
- The lattice is strongly bound together by strong ___ bonds (Silver, ___, and ___)
- The cubic lattice allows for free silver ___ and free ___ to ___ through the lattice
- ___ is added to the lattice (forms the ___ speck in each cubic lattice)
- Acts as ___ to ___ the free silver ___
Silver Halide Crystal Structure
- Resulting shape can be many varying forms
- However, the inner structure takes on a cubic form or cubic lattice
- Each crystal or grain is a cubic lattice
- The lattice is strongly bound together by strong ionic bonds (Silver, bromine, and iodine)
- The cubic lattice allows for free silver atoms and free electrons to drift through the lattice
- Gold-silver sulfide is added to the lattice (forms the sensitivity speck in each cubic lattice)
- Acts as electrodes to attract the free silver ions
When is the time where the silver halides are allowed to grow?
The size of the crystals determines their what?
Which crystals are more sensitive to light or radiation?
Which crystals are less sensitive to light or radiation?
- Ripening stage (silver halides allowed to grow)
- Photosensitivity (what size of crystals determine)
- Larger crystals more sensitive to light or radiation
- Smaller crystals are less sensitive to light or radiation
Mixing Stage
Additives are added to the emulsion
Spectual matching is ___ to match the ___ to the screen’s visual color - “glow” given off by the ___.
What do hardeners do?
What stops the growth of organisms in the wet processor?
What decreases the sensitivity to environmental factors (heat, cold)?
Spectual matching is colored dyes to match the wavelenghts to the screen’s visual color - “glow” given off by the intensifying screen.
- Hardeners prevent physical damage
- Bactericides and fungicides stop growth of organisms in wet processor
- Antifogging agents decrease sensitivity to environmental factors (heat, cold)
What is the last stage of film manufacturing?
What happens during this process?
This process requires extreme precision.
Then the film is ready to use!
- Coating stage
- Emulsion layer applied/glued on the base
Formation of the latent image
What happens when a light or radiation photon strikes a silver halide crystal?
What is caught or attracted to the sensitivity speck?
What will the electron (that has a negative charge) attract?
A single photon may free thousands of electrons for what?
What must be deposited for a black metallic silver crystal to be formed by chemical development of the latent image?
The more black metallic silver crystal created at the sensitivity specks, the…
- Its energy removes an electron from the atom.
- The free electron
- The positive silver ions
- Deposition at sensitivity specks
- At least 3 silver atoms
- The more black metallic silver crystal created at the sensitivity specks, the darker the image
Types of Film
Direct exposure or nonscreen film: ____is used to expose the film. Used in ___ radiography, ___, and exams needing ___.
Intensifying film or screen film: ___-___% of the radiographic image is made with ___ given off by ___.
- Can be purchased with a variety of ___, ___ ranges, film ___ and ___.
Types of Film
Direct exposure or nonscreen film: ONLY RADIATION is used to expose the film. Used in dental radiography, hands, and exams needing best detail.
Intensifying film or screen film: 95-99% of the radiographic image is made with light given off by intensifying screens.
- Can be purchased with a variety of speeds, contrast ranges, film latitude and resolutions.
Special Application Film
M
D
C
L
D
F
Special Application Film
Mammography
Detail extremity radiography
CRT imaging
Laser
Duplication
Fluoroscopic spot
Film Speed: (Emulsion Layer and Size)
___ the emulsion layers, the MORE sensitive to light so ___ the speed of the film
___ the emulsion layers, LESS sensitive to light so ___ the speed of the film
Size of Crystals
___ the crystal size, the MORE sensitive to light so ___ the speed of the film
___ the crystal size, the LESS sensitive to light so __ the speed of the film
Resolution or Detail
___ the emulsion = less detail
___ the emulsion = better detail
___ the crystal size = less detail
___ the crystal size = better detail
Contrast and Film Latitude
Larger crystal and thicker emulsion = ___ contrast film and ___ latitude
Smaller crystal and thinner emulsion = ___ contrast film and ___ latitude
Film Speed: (Emulsion Layer and Size)
Thicker the emulsion layers, the MORE sensitive to light so faster the speed of the film
Thinner the emulsion layers, LESS sensitive to light so slower the speed of the film
Size of Crystals
Larger the crystal size, the MORE sensitive to light so faster the speed of the film
Smaller the crystal size, the LESS sensitive to light so slower the speed of the film
Resolution or Detail
Thicker the emulsion = less detail
Thinner the emulsion = better detail
Larger the crystal size = less detail
Smaller the crystal size = better detail
Contrast and Film Latitude
Larger crystal and thicker emulsion = lower contrast film and wider latitude
Smaller crystal and thinner emulsion = higher contrast film and narrow latitude
Film Storage and Handling
Prior to exposure:
Should be stored ___
Age: See ___
Heat: Must be store below ___°F (___°C)
Humidity: ___-___%
Light: No light ___ in cassette
Radiation: Protect film from ___
Exposed film is very ___ to even ___ exposures of radiation!
Film Storage and Handling
Prior to exposure:
Should be stored on end vertically
Age: See expiration dates
Heat: Must be store below 68°F (20°C)
Humidity: 30-60%
Light: No light leaks in cassette
Radiation: Protect film from radiation exposure
Exposed film is very sensitive to even small exposures of radiation!
Film Identification
Each exposure must include medical record information
- ___ of exposure
- ___ of patient
- Name of ___
- Name of ___
- Patient ___ number
- Type of ___
Film Identification
Each exposure must include medical record information
- Date of exposure
- Name of patient
- Name of institution
- Name of ordering physician
- Patient identification number
- Type of exam
Legal Medical Record = Patient Films
It is the legal responsibility of the ___ to make sure the radiographic images are correctly marked!
Legal Medical Record = Patient Films
It is the legal responsibility of the radiographers to make sure the radiographic images are correctly marked!
