Ch 25 Fluoroscopy Flashcards
the primary function of the fluoroscope is:
to provide real-time dynamic viewing of anatomic structures
the fluoroscope shows the motion of:
circulation and internal structures
angiography is _____ and is now referred to as _____
the visualization of vessels and is now referred ti as interventional radiology
the image intensifier is found:
above the patient
during fluoroscopy the x-ray tube is operated at:
less than 5 mA
the advantage of the image-intensifier is:
increased image brightness
illumination levels are measured in:
units of lumen per square meter or lux
radiographs are visualized under illumination levels of:
100-1000 lux
rods and cones are responsible for:
the sensation of vision
light must first pass through the _____ which is a ______ and then through the ______, where the light is focused onto the _______
cornea which is a transparent protective covering, then through the lens, where the light is focused onto the retina
between the cornea and the lens is the ____, which ____
iris which controls the amount of light entering the eye
the cones are concentrated ______, an area called the _____
cones are concentrated at the center of the retina, in an area called the fovea centralis
rods are found ______, there are ___ rods found in the fovea centralis
rods are found on the periphery of the retina, there are no rods found in the fovea centralis
the rods threshold is _____ and are _____ vision aka _____ vision
2 lux, night vision aka scotopic vision
the cones threshold is ______ and are ____ vision aka _____ vision
100 lux, daylight vision aka photopic vision
visual acuity is
the ability to perceive fine details (cone vision)
the image intensifier raises the illumination into:
cone vision region where visual acuity is greatest
the image intensifier tube receives ______ and converts it into a ______
receives the inmate-forming x-ray beam and converts it into a visible-light image of high intensity
input phosphor is made of _______
CsI Cesium Iodine
the photocathode is:
bonded directly to the input phosphor; thin metal layer usually made of cesium and antimony compounds that respond to stimulation of input phosphor light by the emission of electrons
*the photocathode emits:
electrons when illuminated by the input phosphor
photoemission is:
electron emission that follows light stimulation
output phosphor is made of ______ and is the site of ______
zinc cadmium sulfide and is the site of where electrons interact and produce light
input phosphor has 3 sizes:
sm (10), med (17), lg (25)
magnification mode uses the ____size
smallest size (10)
the patient dose _____ when you use the magnification mode
increases
______ hit the input phosphor and are turned into _____
x-ray photons hit the input phosphor and are turned into light
the input phosphor has a ____ diameter measuring ____
larger diameter measuring 10-40 cm
the light then hit the photocathode where it turns into _____
electrons
the photocathode is made of _____
Cesium Antimony CsSb
the electrons then hit the output phosphor and turn into ______
light
the output phosphor is made of _____ and has a diameter measuring _____
Zinc Cadmium Sulfide ZnCdSO4 and has a diameter measuring 2.5-5 cm (smaller diameter brighter light)
the light exiting the output phosphor is _______ brighter
50-75 times brighter per electron
*brightness gain =
the image is _____ times brighter
BG = minification gain x flux gain
the image is 5,000-30,000 brighter
*minification gain =
(di/do)²
*flux gain =
# x-ray photons : # light photons
(in : out)*conversion factor =
BG x 0.01
the image intensifier tube is ____ long
50 cm
going from input phosphor to output phosphor requires ___ V
25,000 V (25kV)
veiling does what?
decreases image contrast
*MF =
bigger/smaller
the television camera tube is aka _____
the modified version is ____
vidicon
plumbicon
3 ways to make the image brighter:
1) use the smallest output phosphor diameter 2.5
2) technical factors (exposure technique or brightness knob)
3) use more magnification
*the beam splitting mirror does what?
sends the output phosphor image to multiple places
the more line pairs per mm you can see:
the better resolution
x-ray tube operates on _____
filament tube operates on _____
fluoro tube operates on _______
x-ray 5 mA
filament 3-6 A
fluoro less than 5 mA
