Radiographic Film Flashcards
Is to record and store a permanent anatomical image
Film Function
The radiographic image is a ——-
negative image
Medical images are most often displayed on a ____
viewbox
Layers of Conventional Radiographic Film
- Base
- Adhesive Layer
- Emulsion
- Protective Layer
Layers of a Dual Emulsion Film
- Protective coating (gelatin)
- Emulsion (silver halide)
- Adhesive
- Flexible base material
- Adhesive
- Emulsion (silver halide)
- Protective coating (gelatin)
used in mammography, some extremity radiography, camera-produced images and laser-produced images
Single-emulsion films
made of polyester and gives the film stability, functions to support both emulsions and their protective layers
Base
is added to most radiographic film bases to reduce glare and crossover
A blue dye
prevents the emulsion from seperating from the base (when the film is immersed in the processing chemicals of an automatic processor, the emulsion swells and contracts)
Adhesive (Substratum) Layer
Is the most important part of the radiographic film because it is the recording medium for the diagnostic image
Emulsion
The emulsion is composed of ———- and ———- randomly dispersed and suspended in gelatin substance
- silver halide crystals
- silver iodide
is the most commonly used halide in radiographic film because of its sensitivity to the colors of light emitted from screens and to x-radiation
Silver bromide
Modern radiographic film emulsions contain
tabular grain (T-grain) silver halide crystals
are superior to the types of crystals used previously in that they are flat and can be more evenly distributed
T-grain crystals
T-grain crystals’ improved distribution has eliminated?
which gives the image an undesirable grainy appearance
Structure mottle
is the preferred suspending medium for the crystals
Gelatin
Gelatin is the preferred suspending medium because ?
it swells when placed in the develop solution
the swelling allows chemicals to penetrate
The size and distribution of the silver bromide crystals influences 3 film factors
Speed, contrast and Detail
The larger the crystal sizes
the faster the film speed
creates density
The distribution of the crystals within the gelatin affects
image contrast and structure mottle.
the most common type of film used in
conventional radiography.
dual-emulsion or duplitized
film
Light produced in 1 screen will not only expose its adjacent emulsion but also may traverse the film base and expose the opposite emulsion.
crossover, or crosstalk.
reduces the distance between the emulsion layers, thereby reducing the divergence of the light.
A thin base
When the x-ray tube is angled to project the anatomical
information onto the film, information is recorded on
both emulsions, but not directly superimposed, as it
would be if the x-ray tube were not angled.
parallax effect.
Films are classified according to the
spectral sensitivity
of their emulsions.
Films that are sensitive to all colors
Panchromatic
Films that are sensitive to all colors, except red,
orthochromatic
also called supercoating.
Protect the emulsion from scratches and harmful agents
prevents static discharge, and prevents glare when the
radiographic image is being viewed.
Protective Layer
most commonly used film in medical
radiography.
Screen film
Most radiographic film is either
blue-sensitive or green-
sensitive.
is sensitive to blue, violet and
ultraviolet light.
Blue-sensitive film
is very sensitive to green, blue,
violet and ultraviolet light.
Green-sensitive film
also called direct-exposure film.
No Intensifying Screens are used with this type of film.
Nonscreen Film
Nonscreen film is most commonly used for
Industrial
radiography and some dental radiography.
are single-emulsion & are exposed by different sources of light energy to record medical images.
Special Application Film
*One unique characteristic of single-emulsion film is
anti-halation layer
is composed of a dye, & prevents light from reflecting back toward the emulsion after it traverse the emulsion and base.
Anti-halation layer
a prehardened gelatin layer, is added to the adhesive (substratum) layer on the side adjacent to the base.
anti-curl layer
Has only 1 emulsion and is used with single-screen cassettes.
Resolution of extremely small breast lesions is of critical importance in early cancer detection.
Mammography Film
are used in photographic cameras attached to fluoroscopic image intensifiers.
They are directly exposed by reflected light coming from the output phosphor of the image intensifier.
Spot Films
propel the film and continuously present
unexposed sections (frames) for sequential photographic recording of the fluoroscopic images.
Sprocket teeth
It is a roll-type, single-emulsion film with sprocket holes along its edges, constructed and functioning similar to roll-type spot film.
is used in cinefluorography, mainly during cardiac catheterization procedures, and in some other angiographic procedures.
Cine Film
is a single-emulsion film used in special
imaging laser printers.
Laser Film
is a single-emulsion film designed to be sensitive to the color of light emitted by most cathode ray tubes (CRT) or television Monitors.
Video Film
is a single-emulsion film designed to be sensitive to the color of light emitted by most cathode ray tubes (CRT) or television Monitors.
Video Film
Is a single-emulsion and is pre-exposed to a certain
intensity of light by the manufacturer.
Duplication Film
The additional exposure (in excess of the exposure received from the manufacturer) reverses the response of the duplication film through a process
solarization
is a single-emulsion film, designed similar to conventional radiographic film.
Used to produce an image that is void of bony structures
Subtraction Film
2 subtraction films are required:
- One to record a “mask”
- other to record an image of the superimposed original radiograph and mask film.
When electromagnetic energy (e.g. x-rays) interacts with radiographic film, a density is produced within the emulsion.
Latent Image Formation
exists in the imulsion, which is an invisible representation of the radiographed structures.
latent image
The invisible latent image is converted into a ———– after the film is immersed in the developer chemicals of the processor.
Manifest Image
When the developer provides or “loses” its electrons to the metallic silver of the development centers, it is
oxidizes
When the metallic silver “gains” these electrons, it is
reduced
One method of quantitatively measure a
film’s response.
Sensitometry
To perform a sensitometric evaluation of a particular film, ———– must be produced and developed under controlled conditions
sensitometric strip or step-wedge exposure strip
Optical density units are determined based on a
ratio of the amount of original light intensity striking the film (Io) to the intensity of light transmitted through each step(It).
Once the series of steps on the sensitometric strip is read by a densitometer, the OD units are plotted on a graph.
Sensitometric Curves
is a graphical display of the film’s response to exposure and development.
sensitometric curve, characteristic
curve, D log E curve or H and D curve
3 parts of the sensitometric curve
the toe
body (straight-line portion)
shoulder.
sensitometric curve
lighter density steps
toe
sensitometric curve
medium & darker density steps
body & shoulder
sensitometric curve
represents the underexposed portions of the
radiograph , never begins at 0 density because of the blue dye added to the base & the chemical fog density placed on the film during processing.
Toe
The point at which the toe begins slope upward toward the body (straight-line portion) of the curve and signifies the film’s first response to exposure
threshold
- (straight-line portion) – contains the diagnostically useful densities on a radiograph.
- “gamma” or “slope”
- Used to determine film contrast
Body
upper portion where the straight line ends.
Represents the areas of overexposure on a radiograph.
Shoulder
The area of the curve extending beyond the shoulder, where an increase in exposure causes the density to decrease.
solarization region
Quantitative Data obtained from Sensitometric Curves
reveal several film characterizes, including: speed (sensitivity), contrast & exposure
latitude.
Sensitometric curves
Quantitative Data obtained from Sensitometric Curves
represents the film’s sensitivity to exposure. A film with high speed is one that exhibits a strong response to exposure.
Film Speed
of the curve determines the
inherent film contrast.
steepness or slope
- The contrast can be qualitatively determined by simply looking at the —— of the curve.
- The steeper the slope, ————-
- steepness
- the higher the contrast
is the range of exposures that can be used to yield a diagnostically useful range of optical densities on the radiographic image.
Exposure Latitude
Films with more ——– allow the
radiographer more tolerance for error.
wider exposure latitude
An inverse relationship exists between ————, & a reasonable balance must be achieved regarding ———
- film latitude and contrast
- image quality & the desired amount of
exposure latitude.
Film should also be stored within a temperature range
of ———- & a relative humidity range of ————
- 50-70° Fahrenheit
- 40-60%
Boxes of film should be stored with the ———- in
back, using the ——– first.
- newest placed
- oldest film
FIFO system
First In, First Out (FIFO)
To maintain archival quality, processed radiographs should be stored
under controlled conditions
Optimally, they should be stored in a temperature
ranging from ——- Fahrenheit & a relative humidity range of ——-
- 60-80° Fahrenheit
- 30-50%.
Optimally, they should be stored in a temperature
ranging from ——- Fahrenheit & a relative humidity range of ——-
- 60-80° Fahrenheit
- 30-50%.
Care should be taken to avoid bending an unprocessed film ——— may be produced, particularly when the film is being removed from the cassette.
crinkle marks
Film should be slowly removed from the film bin &
cassettes to ——–
avoid static discharge.
