Fluoro Review Flashcards
what is the mA range in fluoro
0.5-5mA
how long is the backup timer
5 minutes
define image intensification
exit radiation from the anatomic structure interacts with the input phosphor for conversion into light
input phosphor
exit radiation to visible light
photocathode
visible light to electrons
electrostatic focusing lenses
accelerates electrons toward an anode to strike the output phosphor
output phosphor
converts electrons to visible light
true or false; the greater the conversion factor or brightness gain, the greater the efficiency of the image intensifier
true
ABC
automatic brightness control
what does ABC do
maintains the overall appearance the image; adjusting the kVp, mA, or both
true or false; fluoro is considered a static form of imaging. Allowing for the imaging of movement of internal structures
false; it is considered dynamic imaging. it uses live x rays captured in video form
true or false; using a low mA setting allows for longer exposure times in fluoro
true
what kinds of material is the input phosphor made of
cesium iodide
outline the steps of image production in fluoro
x-rays -> input phosphor; turns into light -> photocathode; light into e- -> electrostatic focusing lenses -> anode -> output phosphor; e- into light; intensity of the image/ increased brightness
what material is the output phosphor made of
zinc cadmium sulfide
what material is the photocathode made of
cesium and antimony
define flux gain
accelerating the e- to increase the light intensity at the output phosphor
deine magnification gain
the reception in the see of the output phosphor image compared with the input phosphor image; results in an increased light intensity
name the term for the following definition: a product of both flux gain and magnification gain; results in a brighter image on the output phosphor
brightness gain
when is a brighter image created
when accelerated e- strike a smaller output phosphor
with a high conversion factor/brightness gain; it can be said that the II has a _____ efficiency level
high
conversion factor = ___% of brightness gain
1
define conversion factor
the luminance at the output phosphor divided by the input exposure rate
what is the unit to measure for the conversion factor
candela per square meter per milliroentgen per second
example: a brightness gain of 20,000 would have a conversion factor of ____
200
true or false; ABC can be slow to adjust due to pt thickness and density
true
what is another term for magnification mode
multi-field mode
when using mag mode the voltage to the electrostatic focusing lenses is _____
increased
what are the three trifocus lenses
30cm, 23cm, 15cm
how do you find the degree of magnification
dividing the full-size input diameter by the selected input diameter
true or false mag mode increases pt dose
true
how does mag mode effect spatial resolution
it increases spatial resolution
what is the spatial resolution capacity in fluoro
4-6 line pairs/mm
define vignetting
loss of brightness around the edges of the image
what causes a pincushion effect to an image
uneven magnification
what causes a grainy/noisy image
too low mA
