Flashcards in Unit 4, 5, 6 Deck (74):
Who is the first founder of the x-rays? And when did he do it?
Wilhelm Conrad Roentgen
November 8, 1895
First radiographic patient and of what?
Anna bertha roentgen (wife)
How were x-rays discovered?
Working with the crooks tube
Dr Edwin Frost did what?
Credited with making the first diagnostic radiograph
Early protection efforts?
Henri Bequerel did what?
Discoverer of radioactivity
Pierre and Marie Curie did what?
Founded ways to measure the intensity of radiation and finding other elements that emitted radiation
Define Intensifying screen
Device that coverts the energy of the x ray beam into visible light
Intensifying screens, have four layers. What are they?
Base, reflective, phosphor, protective coating
Base layer, location and function? (Intensifying screen)
Farthest from the film
Support the phosphor layer
Reflective layer, location and function? (Intensifying screen)
Between phosphor and base
Redirects the light to the film
Phosphor Layer, location and function? (intensifying screen)
Below protective layer
Converts the energy of x-ray beam to visible light (Heart of the screen)
Protective Coating, location and function? (Intensifying screen)
Closest to the film
Helps eliminate static electricity
What is Luminescence
Any material that emits light in response to some outside stimulation
2 types of Luminescence?
Florescence = Good
visible light emitted only while the phosphor is stimulated
Phosphorescence = Bad
light emitted after the stimulation has stopped
in a screen is called "screen lag" or "afterglow"
Screen speed Defined? (Range)
Screen speeds range from 100 (slow Detail)
to 1200 (very fast, less detail)
Factors affecting screen resolution?
Fast screen speed = Low resolution/detail
Large phosphor crystal size = Low resolution
Thick phosphor = Low resolution
High kVp = lower resolution
Faster image receptors/screens = ?
Fast screens = ?
Slow image receptors/ screens = ?
What is image noise?
deterioration of the radiographic image
What is quantum mottle?
describes the mottled or noisy appearance or the film due to the number or photons exposing it. (salt/pepper)
What is spatial resolution?
ability to produce an accurate and clean image
What is resolution?
a measure of the ability of a system to image two separate objects and visually distinguish one from another
What is a cassette?
holder that contains the film and intensifying screens
How do you care for screens?
do not dig film out of the cassette
do not leave cassette open
Describe screen maintenance.
Cleaned once a month
screen must be completely dry before reloading the cassette
Screen- film contact? bad contact?
Checked by wire mesh test
any areas darkened or blurred = bad contact
should be done annually
Only way to render screen useless?
improper handling and maintenance
Screen affects on density?
**as screen speed increases density increases
**faster screens produce more light per interaction
Screen affects on detail?
increasing screen speed, decreases detail
due to increased quantum mottle at high screen speeds
Screen affects on patient dose
as screen speed increases, patient dose decreases
-exposure techniques can be decreased with faster screens
What is a latent image?
an image that cannot yet be seen, invisible
What is remnant radiation?
x ray that remain after the useful beam exits the patient
What is a manifest image?
the observable image formed when the latent image undergoes the proper chemical processing (final image)
What are your film parts? (4)
Film parts, base? What does it do?
Provides the rigid structures onto which the emulsion is placed
Film parts, adhesive layer? Where is it?
between film emulsion and base
Film parts, emulsion? What is it?
**heart of the x-ray film
Film parts, supercoating, What is it?
surrounds the sheet of film and protects it
Silver halide crystals do what?
Bound by ionic bonds
fixed in the crystal lattice in ion form
Silver halide is what?
active ingredient in emulsion
Silver bromide is what?
material that makes up 98% of the sliver halide crystals in a typical emulsion
Define sensitivity speck
physical imperfections in the lattice of the emulsion layer that occur during the film manufacturing procces
-at or near the surface
Photo interactions with silver halide crystals do what?
forms a latent image (can't see)
What is film speed?
degree to which the emulsion is sensitive to x-rays or light
the faster the speed the more sensitive it is
What is film contrast?
ability of radiographic film to provide a certain level of image contrast
High contrast in film do what?
shows blacks and whites better
Low contrast in film do what?
shows shades of gray better
What is film latitude?
range of techniques
When handling film, what do you do?
don't bend, crease or fold
must have clean hands
avoid lotion and creams
What are artifacts?
any irregular density on a radiograph that is not caused by the proper shadowing of an object by the primary beam
How do you properly store film?
in a dry cool place (fridge)
heat and humidity can cause increase in fog
and reduce contrast
Automatic film processing, what's the purpose?
intensifies latent image and makes it visible (manifest image)
What is the sequence of automatic processor?
What does the developer do in automatic processing?
converts latent image (invisible) into manifest image (visible)
What 3 factors affect development in automatic processing?
developer temperature 95 F
What does the fixer do in automatic development?
removes undeveloped sliver halide crystals from the film and fixes (or sets) the film
contributes to archival quality
What does the wash do in automatic development?
Removes residual chemicals left in emulsion
What does the dryer do in automatic development?
blows warm air over both sides of the film to completely dry the film
Processor maintenance, times?
Daily = crack lid open
weekly = cleans crossover and roller assemblies
monthly = completely cleans and chemicals changed
Processing affect on density?
increase time/ or temperature = increase density
Processing affect on contrast?
increase time/ or temperature = decrease in contrast
What is the PSP plate?
Photostimulable phosphor plate
PSP plate layers?
PSP plate, protective layer?
protects phosphor layer
PSP plate, phosphor layer?
the active layer, trap electrons during exposure
PSP plate, reflective layer?
reflects light emitted towards the front (photodetector)
PSP plate, conductive layer?
reduces static electricity
PSP plate, support layer?
provides the ridged edges
PSP plate, backing layer?
soft layer that protects back of cassette
What is turbid?
random distribution of phosphor crystals within the active layer
What does CCD stand for?
What does TFT stand for?
What does PACS stand for?
Picture Archiving & Communications System