Unit 4, 5, 6 Flashcards
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)
Hand
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?
Metal helmets
Heavy aprons
Lead screens
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 = ?
Low resolution
decreased detail
high resolution
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?
Avoid handling
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
develop film
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