FLUOROSCOPY

fluoroscopy

x-rays in motion

zinc-cadmium sulfide

the first screen placed over patient’s body in x-ray beam

30 minutes

what is the time before exam that radiographers take to adjust in red light?

1950

what year image intensifier developed?

100-150 lux

the level of brightness that fluoro used at the same level as radiographs

carriage

it also has the power drive control, spot film election, and tube shutters

barium swallow

used to observe the upper GI tract

barium enema

used to observe lower GI tract

cornea

part of the eye where the light passes

iris

part of the eye that acts as a diaphragm

rods

sensitive to low lights

scotopic vision

also known as the night vision

cones

less sensitive to light

phototopic vision

this is also known as daylight vision

fixed fluoroscopy unit

mounted no closer than 15 inches or 38cm to patient

mobile fluoroscopy unit

may be brought no closer than 12 inches or 30cm to patient

remnant x-ray

image intensifier receives ____ and converts it to light

input screen

it converts incident x-rays into light photons

photocathode

it converts light photons into electrons

electrodes

focalization of electrons onto the output phosphor

output screen

conversion of accelerated electrons into light photons

cesium iodide

element that composes the input phosphor

photoemission

emits electrons when struck by light

zinc-cadmium sulfide

element that composes the output phosphor

electron optics

“the engineering aspect of maintaining proper electron travel”

flux gain

the ratio of number of light photons at the output phosphor to the number of x-rays at the input phosphor

minification gain

the ratio of the square of the diameter of the input phosphor to the square of the diameter of the output phosphor

brightness gain

the product of minification gain and flux gain

conversion factor

is a measure of its ability to convert x-ray energy into visible light and increase brightness

multified image intensification

it allows focal spot point change to reduce field of view and magnify the image

25/17

the most popular multifield image intensifiers

25/17/12 or 23/15/10

tri-field tubes for multifield image intensifiers

digital fluoroscopy

is a digital x-ray imaging system that produces dynamic images obtained with an area x-ray beam

conventional fluoroscopy

produces a shadowgraph type image on a receptor that is directly produced from the transmitted x-ray beam

pulsed progressive fluoroscopy

generator can be switched on and off rapidly

interrogation time

tube switched on and meets selected levels of kVp and mA

extinction time

time required for the tube to be switched off