Fluoroscopy Exam Questions and
Answers All Correct New Update
What is the difference between fluoroscopy and radiography? - Answer- -fluoro is
dynamic
-radiography is static
What is the primary difference between conventional and image intensified fluoroscopy?
- Answer- - Brightness
What is the main job of the II (image intensification) - Answer- -convert x-rays to light
-II replaced conventional dim fluoro screen
-raises illumination to cone vision for better visual acuity
-ABC maintains brightness
What does the II envelope do? - Answer- -creates a vacuum to help electrons to have a
straight path
What is the function of the input phosphor and what is it made of? - Answer- -to take
remnant x-rays and convert to light
- CsI - Cesium Iodide
-5nm in diameter
- light piping for better spatial resolution due to less light spread
-light intensity proportional to number of x-ray photons
After input phosphor turns x-rays to light, what happens next? - Answer- - light hits
photocathode and is turned into electrons
-number of electrons is proportional to light intensity
What does the output phosphor do and what is it made of? - Answer- -turns electrons
back to light
-zinc cadmium sulfide
-much smaller than input phosphor
-energy focused on a smaller area = increased brightness
What is the voltage potential and why is it needed? - Answer- -25kV
-to ensure that electrons are accelerated from photocathode to anode
What focuses the electron beam onto the anode and output phosphor? - Answer- -
electrostatic lenses
What is the purpose of the II? - Answer- -intensify signal
, -stronger signal = more brightness = better visual acuity of anatomy
How does the II intensify signal? - Answer- 1) Flux gain
2) Minification gain
What is flux gain? - Answer- -more output light photons than input x-ray photons
-# of output light photons/ # of input x-ray photons
What is minification gain? - Answer- -same intensity of input phosphor focused onto
smaller area of output phosphor
- (Di/Do)^2
-ratio of square of input phosphor diameter to output phosphor diameter
-input phosphor intensity focused onto smaller output area via electrostatic lenses
What is responsible for flux gain? - Answer- -characteristics of input and output
phosphor
What is responsible for minification gain? - Answer- -size of input and output phosphor
What is the brightness gain formula? - Answer- -minification gain X flux gain
-brightness gain = ratio of illumination intensity at output phosphor to radiation intensity
at input phosphor
What is brightness gain? - Answer- -the conversion factor
CF = output phosphor illumination (cd/m^2)/ input phosphor exposure rate (mGya/s)
What decreases brightness gain? - Answer- -tube age and use
-as tube ages, pt dose must be increased to maintain brightness
input phosphors: - Answer- -10-40 cm
output phosphors: - Answer- -2.5-5 cm
Brightness gain: - Answer- -5,000 - 30,000
How do you get the proper quantity for expressing image intensification? - Answer- -
multiply by .01
-50 – 300
What is fluoroscopy? - Answer- -dynamic images
-real time images
-use of contrast media
What is spot films? - Answer- - radiographic images taken during fluoro
-static image
Answers All Correct New Update
What is the difference between fluoroscopy and radiography? - Answer- -fluoro is
dynamic
-radiography is static
What is the primary difference between conventional and image intensified fluoroscopy?
- Answer- - Brightness
What is the main job of the II (image intensification) - Answer- -convert x-rays to light
-II replaced conventional dim fluoro screen
-raises illumination to cone vision for better visual acuity
-ABC maintains brightness
What does the II envelope do? - Answer- -creates a vacuum to help electrons to have a
straight path
What is the function of the input phosphor and what is it made of? - Answer- -to take
remnant x-rays and convert to light
- CsI - Cesium Iodide
-5nm in diameter
- light piping for better spatial resolution due to less light spread
-light intensity proportional to number of x-ray photons
After input phosphor turns x-rays to light, what happens next? - Answer- - light hits
photocathode and is turned into electrons
-number of electrons is proportional to light intensity
What does the output phosphor do and what is it made of? - Answer- -turns electrons
back to light
-zinc cadmium sulfide
-much smaller than input phosphor
-energy focused on a smaller area = increased brightness
What is the voltage potential and why is it needed? - Answer- -25kV
-to ensure that electrons are accelerated from photocathode to anode
What focuses the electron beam onto the anode and output phosphor? - Answer- -
electrostatic lenses
What is the purpose of the II? - Answer- -intensify signal
, -stronger signal = more brightness = better visual acuity of anatomy
How does the II intensify signal? - Answer- 1) Flux gain
2) Minification gain
What is flux gain? - Answer- -more output light photons than input x-ray photons
-# of output light photons/ # of input x-ray photons
What is minification gain? - Answer- -same intensity of input phosphor focused onto
smaller area of output phosphor
- (Di/Do)^2
-ratio of square of input phosphor diameter to output phosphor diameter
-input phosphor intensity focused onto smaller output area via electrostatic lenses
What is responsible for flux gain? - Answer- -characteristics of input and output
phosphor
What is responsible for minification gain? - Answer- -size of input and output phosphor
What is the brightness gain formula? - Answer- -minification gain X flux gain
-brightness gain = ratio of illumination intensity at output phosphor to radiation intensity
at input phosphor
What is brightness gain? - Answer- -the conversion factor
CF = output phosphor illumination (cd/m^2)/ input phosphor exposure rate (mGya/s)
What decreases brightness gain? - Answer- -tube age and use
-as tube ages, pt dose must be increased to maintain brightness
input phosphors: - Answer- -10-40 cm
output phosphors: - Answer- -2.5-5 cm
Brightness gain: - Answer- -5,000 - 30,000
How do you get the proper quantity for expressing image intensification? - Answer- -
multiply by .01
-50 – 300
What is fluoroscopy? - Answer- -dynamic images
-real time images
-use of contrast media
What is spot films? - Answer- - radiographic images taken during fluoro
-static image
