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Exposures- Ch.36 Fluoroscopy

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kkaitlyn96's version from 2017-04-02 19:05

Section 1

Question Answer
Dynamic imagingmotion exam, checks anatomy
Static imagingnon motion, standard diagnostic imaging
What was the first dynamic imager called?cryptoscope
When was the cryptoscope invented?Feb 1896
Who invented the cryptoscope?Salvioni
What was the second dynamic imager called?Skiascope
Who invented the Skiascope?McGie
What did Edison invent?fluoroscope
Who does the credit go to?Edison- 1896
Who was the first to die due to xrays? When?Clarence Dalley in 1904
memorize

Section 2

Question Answer
What was the biggest issue with the older fluoro?direct view, which also caused direct exposure to eyes and face
When the hazards of xrays were known, what did they use?a series of mirrors
When were image intensifier tubes invented?1948
What did the the image intensifier do?allowed light to be transformed into video but detail was lost
When did digital fluoro start to get popular?2005
what supports the image intensifier?carriage
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Section 3

Question Answer
What is different about fluoro tubes?operate longer and lower mA
What is the range of mA in fluoro tubes?.5 to5mA
Fixed units SOD in and cm15in, 38cm
Mobile units SOD in and cm12in, 30cm
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Section 4

Question Answer
Image intensifiervacuum
What does the input screen do?absorbs photons and emits light
What is the input screen made out of?.1-.2 layer of sodium activated cesium iodide phosphors (CsI)
What is the shape of the input screen and why?concave to keep a perfect distance between input and output
Surface range in input screen is what?6 in to 23 in
CsI absorbs _________% of photons66
There is a _________ relationship between photons absorbed and light photons given offdirect
decrease magnification= _________ detail= _________ distortionincrease, decrease
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Section 5

Question Answer
What does the photocathode do?absorbs light and emits electrons- photoemission
What is the photocathode made of?photoemissive metals (cesium and antimony compounds)
What does the electrostatic lenses do?absorbs electrons and accelerates toward the anode
What happens at the focal point?the image reverses
When the electrons accelerate and get focused what gets created?brightness gain
If you increase the speed of the electrons, what happens with the focal point and magnification?focal point moves toward the input screen which magnifies the image
Are the electrostatic lenses negatively or positively charged?negative
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Section 6

Question Answer
Magnification- Where do electrons go?electrons guided to positive anode with negatively charged electrostatic plates
increase voltage to plates, _________ electrons streamincrease
increase stream= focal point closer or farther from the input screencloser
If the focal point is closer to the output screen = __magnificationdecrease
Magnification equationinput diameter/ diameter during magnification
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Section 7

Question Answer
What is the anode?positive charge plate right before the output screen
What does the anode do?focus, narrows the beam to the output screen
What is the anode's charge?about 25 kv
what does the output screen do?absorbs electrons and emit light
what is the output screen made out of?glass fluorescent screen, zinc cadmium sulfide phosphor
Phosphor is __mm in size and screen is __mm thin1-2; 4-8
As electrons hit the output screen what happens?they are converted into light isotropically and a filter directs the light out
What does the tv camera do?converts electrical signal and emits electrons
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Section 8

Question Answer
Brightness gainmeasurement of increase intensity of the image (overall brightness)
What is brightness gain determined by?minification and flux, amount of light generated and output screen
Brightness gain formulaminification x flux
Flux gain is also known as electron gain
Minification gainresult of number of electrons produced in the input screen and compressed to exit the output screen
Minification gain formulainput screen diameter^2/output screen diameter^2
Flux gainmeasurement of increase in light photons due to the conversion efficiency of the output screen
Flux gain formula# of light photons/ electron
memorize

Section 9

Question Answer
Automatic brightness controlautomatically adjusts exposure factors needed to give an adequate visual image
Quantum Mottle/NoiseInsufficient radiation/mAs
Vignettingpincushion distortion, edges of image has decrease brightness because electrons flare out due to repelling eachother
Pulsed fluorobursts of radiation in set intervals
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