RAD-172 FLUOROSCOPY

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who invented the flouoroscope in1896

thomas edison
regular xray is _____
floro xray is _____
- static
- dynamic
what is the lowest portion of the body that the tube can be from the patient when using floro
what is this distance called
- 15cmm
- source to skin distance
what are the two light receptors of the eye

rods and cones
what is photopic vision

when the cones of the eyes require bright light or daylight
scotopic vision

when rod vision is used in dim light or complete darkeness (like in darkroom of the xray to process films)
what is the best position of the body for fluid to dump into the small intestine

RAO
what is the primary function of fluoroscopy

is to perform dynamic studies to visualizethe motion of internal structures and fluids
what permits the IR to be reaised and lowered to vary the ofd and gain maximum resolution while the tube remains in position

C arm it permits scanning the length and width of the table
what is a carriage
what structures does it include
- the arm that supports the equipment suspended over the table
- image intensifier, control for power to drive the carriage, spot film selection, tube shutters (collimation), on/off dead man switch, height lock
where is the xray tube in a floro unit

in the table
what is the floroscopic range mA range
how much is the typical diagnostic range for an xray tube
why is range so low
- 0.5-5.0 mA
- 25-1200 mA
- because floro tubes must operate for long periods of time
a fixed SOD of ____ is used to prevent any closer movemtn of tube

15 in
what is the purpose of image intensification tubes (2 reasons)
- designed to amplify the brightness of an image
- reduce patient dose while maintaining image qualtiy
anything with the word screen or cathode means what
- screen = means it produces light
- cathode means it produces electrons
what general technical fasters are used to increase brightness in fluoro

high kvp low mA
what is the first layer of the II (image intensifier)
what is this layer made out of and what is the function
- input phosphor screen
- made out of cesium iodide
- purpose to absorb xrays into & emit light photons
what is the second layer of the II
what is this layer made of
- photocathode layer
- cesium & antimony compounds
what are the two portions at the top of the II
what structure is between the anode and the photocathode parts of the II
- the anode then the output fluorescent screen
- electrostatic lenses
how does fluoro work
- after beam exits patient it strikes the input phosphor screen of the II (which absorbs photons to light
- these photons then strike the photocathode layer which is in contact with the input screen (also absorbs light photons and emits electrons)
- electrons are shot thru the II from photocathode and strike the anode and output screen
- then output screen absorbs electrons and emits light photons (50-75x as many more light photons now created)
what is the purpose of electrostatic lenses
where are they located
what focuses the stream in this direction
- they are used to accelerate and focus electrons to the anode and output screen
- located in the II just out side of the divergence of the stream of electrons heading to the anode output side
- the opposite charges between the electrons and the lenses
voltage:
potential voltage:
- energy that sends the electrons to the output side
- the difference of energy in electrons from the photocathode side to the output screen side
the output phosphor screen is composed of

zinc cadmium sulfide
how else can the xray tech operate the the fluoro machine

by a foot pedal (dead man type)
back i nthe day what did radiologist have to do before fluoring

they had to make their eyes adapted to the dark because image brightness was very low

Author

anatomy12

271524

Card Set

RAD-172 FLUOROSCOPY

Description

xray

Updated

2014-04-25T00:11:13Z

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