Imaging on film Flashcards
Cassette
film holder designed to contain one pair of intensifying screens and one sheet of film
cassettes must
-be sturdy
-not break in cold conditions
-inflexible and not warp
-have secure latches
-have radiolucent front
-have balanced weight front to back
-contain leded foil or steel back to absorb radiation
-good contact across film/screen
-washable material on the outside
cassette storage
should be stored upright on a counter or in a cabinet protected from radiation
Intensifying screens
provide a faster and more efficient method of image production
intrinsic conversion efficiency
the rate at which x-rays are converted to light by the individual phosphors on t he screen
screen aging response
as the screens age the response of the phosphors reduces in brightness and speed
slow speed systems
-thinner emulsions
more details
fast speed systems
-thicker emulsions
reduces radiation to patient and reduces spatial resolution
Blue systems
-screens emit violet blue light
-require blue receiving film
-various speeds of conversion efficiency
-being phased out
-only film until 1981
Green systems
emit green or blue-green light
-require green receiving film
-usually demonstrate single speed conversion efficiency
Luminescence
process by which intensifying screens react to incoming radiation
Fluorescence
instntaneous reaction that lasts exactly as long as the phosphor is stimulated
Phosphorescence
occurs when the phosphor continues to emit light after the stimulation has ceased
Intensifying screen wear
the screen becomes worn from years of images and is unable to uniformly convert x-rays to light
Latent image
image that is formed but invisible until processed either manually or in an automatic processor
