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Fluoroscopy
N/A
34
Physics
Professional
03/20/2013

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Term
used for studies that require observation of dynamic body functions (peristallic motion)
examination of moving internal structures and fluids
Definition
fluoroscopy
Term
fluoroscopic input screen
Definition
composed of sodium avtivated cesium iodide phosphors
phospors emit light photons after interacting with xrays, and turns xray beam into light
a thin protective coating is applied to prevent a chemical reaction with the photocathode
Term
image intensifier tube
Definition
makes image bright
recieves the image-forming xray beam and converts it into a visible light image of high intensity
Term
automatic brightness control
Definition
cruise control
allows operator to select an image brightness level that is maintained automatically by varying kVp, mA, and pulse time
Term
automatic exposure control
Definition
terminates exposure when prper radiographic density is obtained
Term
3 main parts in fluoroscopic unit
Definition
xray tube
table
image intensifier
Term
tube table distance shall be a minimum of ____ inches
Definition
12
Term
converts an xray beam into visible light
mounted inside a metal container to prevent rough handling
Definition
image intensifier tube
Term
most image intensifiers are ____, which allows for great flexibility
Definition
multi-field (different sizes of input phosphor screen)
Term
Image Intensifier tube parts
Definition
-input phosphor
-thin, transparent, adhesive layer
-photocathode
-electrostatic focusing lens
-anode
-output phospher
Term
xray energy is converted to light of visible photons
coasted onto concave surface of II tube
Definition
input phosphor
Term
bonds the input phosphor to photocathode
prevents interaction of crystals
Definition
thin transparent adhesive layer
Term
a thin metal layer composed of cesium and antimony that takes light from input phosphor and emits electrons

xray-> light photons-> electrons
Definition
photocathode
Term
_____ emitted from photocathode are directly proportional to intensity of light falling on it

more remnant radiation, more light, more ____ in patient
Definition
electrons
Term
negatively charged, maintains a precise path from the photocathode to the output phosphor
located along length of the image intensifier
Definition
electrostatic focusing lens
Term
positvely charged
circular plate with aa hole in the middle thorugh which electrons pass to the output phosphor
draws negative electrons and accelerates them to output phosphor
Definition
anode
Term
anode is supplied with about ___kV
Definition
25 kV
Term
makes image brighter
site where electrons interact and produce light
made of zinc cadmium sulfide crystals and plated with a thin layer of aluminum
Definition
output phospher
Term
each photoelectron that arrives at the output phosphor results in ___ to ___ times as many light photons as were necessary to create it
Definition
50-75
Term
ratio of the number of light photons at the output phosphor to the number of xrays at the input phosphor
Definition
flux gain
Term
flux gain
Definition
FG= output light/ input xrays
Term
the ratio of the square of the diameter of the input phosphor to the square of the diameter of th output phosphor
Definition
minification gain
Term
minification gain
Definition
MG= (d1)/ (d2)^2
Term
the product of minification gain and the ratio of the number of light photons at the output phosphor to the input phosphor
Definition
brightness gain
Term
brightness gain
Definition
BG= MG x FG
Term
a measure of the speed of the screen
Definition
intensification factor
Term
ratio of number of light photons at the output phosphor to the number of xrays at the input phosphor
Definition
flux gain
Term
flux gain
Definition
= #of output light photons/ #input xray photons
Term
intensifying factor
Definition
measures efficiency of intensifying screens
Term
provide greater flexibility in all fluoroscopic examinations
zoom in/ out
Definition
multifield intensifiers
Term
magnification
Definition
better spatial resolution
better contrast resolution
higher patient dose
Term
also known as "white noise"
measured as the signal to noise ratio
increased noise has an inverse relationship to contrast
Definition
noise
Term
ability of imaging systems to accurately disply objects in a two dimensional format
Definition
spatial resolution
Term
image intensifiers are capable of increasing image brightness _____times
Definition
500-8000 times
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