film Flashcards
Focal areas of exposed film in the shape of what?
bolt of lightening
Film screen contact is negatively affected by all the following:
o Foreign material in the cassette or on the screen
o Dents due to objects dropped on screen or closed inside the cassette
o Damage due to improper mounting of screen
o Deterioration of the padding layer
o Warping of the screen from becoming wet
give an example of “single emulsion film”
Mammography film
The emulsion on film is what?
Silver halide microcrystals (active ingredient)
o Silver bromide - 90%
o Silver iodide - 10%
T/f Silver sulfide (sensitivity center)?
True
What is a latent image?
The pattern of exposed and unexposed crystals on a film BEFORE development in the processor
The following can cause exposure of film:
o Light o X-Rays o Heat o Certain chemicals or chemical fumes o Pressure o Age
Film performance characteristics:
o Sensitivity (speed)
o Contrast
o Spectral sensitivity
What is Spectral sensitivity?
portion of electromagnetic spectrum the film is most sensitive to.
What is Latitude?
term used to describe the range of densities that can be recorded on the film
Wide latitude film is best when:
you desire low contrast radiographs (i.e. chest radiograph)
Short latitude film is best when:
you desire high contrast radiographs
film Contrast & Latitude are _____ related
inversely
Establishing the Speed Index involves what?
finding the step on the sensitometric strip that has the closest
optical density to 1.0
Contrast Index is the difference in radiographic density between what?
the Speed Index reading and the optical density reading (using the densitometer) that is two steps darker on the sensitometric strip
