image intensification fluoroscopy

what are the three types of fluoroscopy

direct/conventional fluoroscopy

image intensification tube

digital systems

what is the fluoroscopic imaging capability that provides single-capture still images similar to radiography

static (spot film)

what is the fluoroscopic imaging capability that provides continous real-time imaging in motion

dynamic (fluoroscopy, cinefluoroscopy)

what is the actual recording of the dynamic imaging

cinematic

cine-fluoroscopy

“cine”

rods

night vision

black and white only

takes longer to adaptwh

what is the scientific name for night vision

scotopic

cones

photopic vision

detects color and fine detail

adapt quickly

are rods or cones used in fluoro

rods

what does the image intensifier do

converts X-rays into a visible light image of high intensity

how much does the image intensifier amplify image brightness

increases brightness 500-800 times

automatic brightness control (ABC) AKA

automatic exposure rate control (AERC)

this automatically adjusts exposure factors in response to variations in thickness and density of anatomy or contrast material during fluoroscopy

automatic brightness control (ABC)

the concentration of photoelectrons at the input phosphor compared to the output phosphor

minification gain

this is a type of blooming that is described as a contrast reducing haze on the image

veiling glare

what is veil glare caused by

scattering of x ray light

electrons inside the image intensifier tube

how is veil glare fixed

use a grid

use appropriate collimation

the measure of the ability of the image intensifier to increase the brightness level of the image

brightness gain

kinetic energy gained by photoelectrons as they are accelerated from the photocathode to the output phosphor

flux gain

this is a decrease in image brightness

vignetting

what is vignetting caused by

curved input phosphor and object to image distance

what does vignetting effect

reduces contrast and image detail on the edges of the image

how do you correct vignetting

image processing

adjust II

reducing OID

what does the input phosphor of the II tube do

converts incoming x ray photons into visible light photons

helps in reducing image noise and improving contrast

what does the output phosphor do

converts accelerated electrons back into visible light photons

produces the final intensified image displayed on the monitor

what does the anode do

a positively charged component that attracts and accelerates electrons towards the ouput phosphor

plays a role in image brightness and contrast enhancement

what does the photocathode do

comprised of photoemissive metal: cesium and antimony

in direct contact with the input phosphor to prevent divergence of the light

photoemissive material that absorbs the light photons and emits electrons via photoemission

what do the electrostatic focusing lenses do

series of charged electrodes that focus and accelerate electrons

directs electrons towards the anode

helps in maintaining image clarity and magnification control

what does letter A demonstrate

output phosphor

what does letter B demonstrate

anode

what does letter C demonstrate

electrostatic focusing lenses

what does letter D demonstrate

photocathode

what does letter E represent

input phosphor

what is the input phosphot made of

cesium iodide

what is the output phosphor made of

zinc cadmium sulfide

what is the minimum SSD for fixed units

15” or 38 cm

what is the minimum SSD for mobile units

12” or 30 cm

what is photoemission

absorbs light photons and emits electrons

where does photoemission occur

in the photocathode

what is the mA range used in fluoroscopy

0.5 - 5.0mA

what happens to patient dose when frames per second increase

when frames per second increases = patient dose increases

what happens to patient dose when frames per second decreases

when frames per second decreases = patient dose decreases

what happens to patient dose when magnification mode is used

when magnification mode is used patient dose increases

where is the tube located in fluoroscopy

located under the patient

what is the image intensification tube enclosed with and what does that maintain

enclosed in a glass envelope to maintain a vaccum

what part of the II tube is concave and the largest

input phosphor

what happens to magnification when the focal point moves

magnification occurs when focal point moves closer to input and farther from output

what happens to contrast with magnification

better contrast resolution

what happens to FOV with magnification

decreased FOV

after how long of fluoro will the alarm sound

after 5 minutes of continuous fluoroscopy

what is the function of the CCD and CMOS in fluoro

the electrical device that collects light photons from the output phosphor and converts them into electrons

what is the unit of measure for luminous intensity

candelas

what is the output phosphor measured in

candelas

what is the source of technologist radiation

the patient is the primary source of technologist radiation

what are the radiation protections steps the technologist should take

if you are in the room stand behind the radiologist

tube should always be under the patient if possible

stand on the II side of the c-arm

what is backscatter

the largest amount of scatter radiation is produced where the x ray beam enters the patient

where should you stand to receive the least dose

stand on the image receptor (intensifier II side) of the c-arm