lesson 3 Flashcards
contains phosphor to convert x-ray into light
intensifying screen
the emission of light from the screen when stimulated by x-ray
luminescence
phosphor ability to emit visible light during x-ray
fluorescence
emission of light after x-ray exposure has been done
phosphorescence
layers of IS
- protective coating
- phosphor
- reflective layer
- base
three rare earth (green emission) elements
- gadolinium
- lanthanum
- yttrium
high atomic number so that absorption is high
quantum detection efficiency
emit a large amount of light per x-ray absorption
x-ray conversion efficiency
light emitted must be proper wavelength (color) to match the sensitivity of the x-ray film
spectral matching
continuing emission of light after exposure of the phosphor to x-rays
phosphor afterglow
it intercepts light headed in other directions and redirects it to the film
reflective layer
serves principally as mechanical support for the active phosphor layer
base
describes how efficiently x-rays are converted to light
screen speed
defines as the ratio of exposure required to produce the same object detail
intensification factor
term use to describe the deterioration of a radiographic image
image noise
refers to random nature by which x-rays interact with the image receptor
quantum mottle
ability to produce an accurate and clear image of the screen
spatial resolution
ability to image similar tissues such as liver and pancreas
contrast resolution
consist of lead lines separated by interspaces of equal size
line-pair test
rare earth phosphors efficiently convert xray into usable light
phosphor composition
the thicker the phosphor layer, the higher the detective quantum efficiency
phosphor thickness
the presence of a _ increases screen speed but also increases image blur
reflective layer
to control the spread of light
dye
larger individual phosphor crystals produce more light per x-ray interaction
crystal size
