Fluoroscopy Flashcards by Victor Castillo

Fluoroscopy

dynamic radiographic examination, compared to diagnostic radiography; active diagnosis

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who was credited with the invention of Fluoroscopy

Thomas A. Edison; 1896

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what is the imaging receptor called for Fluoroscopy

Fluoroscopy screen

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types of Fluoroscopy equipment

C-arms, so that the tube is always alined with the Floro. screen. under table units and over table units.

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what is the carriage

arm that supports the equipment suspended over the table

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are floroscreens only suspended over the table?

they can either be suspended over the table or placed under the table

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how do Floro towers operate; technique wise?

longer period of time at a lower mA

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what is the mA range?

.5-5.0mA

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how does the X ray tube Floro. collimate

electronically controlled shutters

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magnification gain formula

input screen diameter^2/ output screen diameter^2

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Flux gain is the measurement of what

measurement of the increase in light photons due to the conversion efficiency of the output screen

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how can brightness gain be calculated?

minification gain X flux gain

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Automatically maintain satisfactory fluoroscopic image density and contrast, is referred to as

ABC= Automatic Brightness Control

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what does ABC do

controls density compensation; vary the mA and kVp

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how do you regulate the primary beam of a flouro

varying kVp, mA, and pulse time

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resolution in flouro

depends on geometrical factors

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types of distortion in flouro

size and shape

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how is size distortion created

Magnification caused by OID

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how is shape distortion seen

geometric problems in the shape of the image intensification tube

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Vignetting effect

edge distortion prob. in image intensification tube

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Quantum mottle in flouro ?

basically anything that is affecting the total number of photons arriving at the retina; radiation output, beam attenuation by the subject, the conversion efficiency of the input screen, magnification gain, flux gain, total brightness gain, viewing system, and the distance of the eye from the viewing system

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Video Viewing systems

commonly used in fluoroscopic viewing system
it is made up of video camera attached to the image intensification tube output phosphor and a display monitor for viewing.

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what is a video monitor in flouro

high- resolution output screen that receives the final processed signal from the fluoroscopic processor

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what factors separate Digital fluoroscopy

high speed generator operating in a pulse progressive fluoroscopy mode; basically keeps the X-ray production of the X-ray tube in sync with the detector signal, so that pulses of the signal are received by the image processing unit.

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interrogation time is what

the length of time required for the generator to come on and achieve the necessary kVp and mAs levels

Digital flouro pixels rage from

200 um and 300 um (1-2 Ip/mm)

what is the processor of most digital fluoroscopy systems?

8-bit processing capability

what is the amount of exposure to skin that a flouro system gives to the patient

1-3 R/min; should not exceed 10 R/min

lead gloves have what Pb/eq

.5 mm Pb/eq

lead aprons should have what Pb/eq

.5 mm Pb/eq

the slot where the gonad shild goes should have how much Pb/eq

.25 mm Pb/eq

image intensifier

increase brightness, which means no need for night vision (scotopic) its unit is Lamberts (L) brightness depends on mA(less than 5 mA not mAs remember (single phase)) kVp and part

what is the typical fluoro. intensity

2.1 R/min for each mA at 80 kVp, and NO more than 10R/min at table top

overhead intensity is?

what is the process if the image intensifier

incident x-ray beam> input phosphor> emits light> photocathode> electrons> photoemission> electrostatic lens guide the electrons to stimulate the output phosphor>emits light

ABS

automatic brightness stabilization

AGC

automatic gain control; adjusts the degree of amplification of the electronic signal

does AGC affect patient dose

does not very patient dose

what is AGC affect on image noise

increases image noise

flux gain formula

of output light photons/ # of input light photons

magnification formula for conventional rad.

SID/SOD

what is the formula for fluoroscope magnification

ratio if the input diameter (without a square)

what are the advantages of multi field imaging

smaller area viewed magnification, dimmer, but improves image quality

how do we calculate patient dose

ratio of input diameter squared

distal end of the T.V camera

has an electrical gun that shoots electrons toward the proximal end. gun has a filament and via thermionic emission, emits electrons, then they go to the proximal end that has the target. light from the output Phosphor goes to the target. THE VIDEO SIGNAL CAN ONLY BE CREATED IF BOTH, THE LIGHT AND THE ELECTRONS HIT THE TARGT AT THE SAME PLACE AT THE SAME TIMEW

TV Monitor

monitor changes video signal to a visible image | units are lp/mm

what is Voxel?

volume of each pixel. | it is the weakest link to resolution

what is the order from highest to lowers dose

cassette spot film, cine, then spot film

how do you calculate minification

diameter of input^2/ diameter of output^2

when is Flux increased

when mA is increased

what is inside the TV monitor

cathode ray tube

where is a spot film cassette placed and what phase generator is used when taking the image

it is placed between the image intensifier and the patient | it uses a three phase generator

what are spot film 105, what generator is used and is it in continuous flouro when exposing the 105 film

basically like the ancient film rolls but twice or three times that size. it exposes one frame at a time it uses a single phase generator on exposure photo signal from output phosphor of the Image intensifier then its converted to an image with spot film

optic system

used in early fluoroscopy. | uses reflective mirrors to direct the output screen image to the viewer

how is a cine film used, what generator does it use and is it a continuous flouro

cine films are used in Cath lab uses a single phase generator has a higher exposure dose than 105 film b/c of the continuous flouro; has better resolution as well

where is the optic system located

at the distal end of the image intensifier

where is the T.V camera located and how does it get to the computer

at the distal end of the image intensifier and can go from the image digitizer and send a digital signal to the computer or can go from T.V camera to TV monitor via video signal then to the computer via digital signal

where is the spot film camera

is at the distal end of the image intensifier

what are the cine sizes

35mm or 16mm cine

what are the spot film sizes

105, 90, and 70mm spot film

move much brighter does brightness Gian make an image

5000 to 20,000 times brighter

Fluoroscopy Flashcards

(61 cards)