Card Set Information

2014-04-24 20:11:13

Show Answers:

  1. who invented the flouoroscope in1896
    thomas edison
  2. regular xray is _____
    floro xray is _____
    • static
    • dynamic
  3. 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  
  4. what are the two light receptors of the eye
    rods and cones
  5. what is photopic vision
    when the cones of the eyes require bright light or daylight
  6. scotopic vision
    when rod vision is used in dim light or complete darkeness (like in darkroom of the xray to process films)
  7. what is the best position of the body for fluid to dump into the small intestine
  8. what is the primary function of fluoroscopy
    is to perform dynamic studies to visualizethe motion of internal structures and fluids
  9. 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
  10. 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
  11. where is the xray tube in a floro unit
    in the table
  12. 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
  13. a fixed SOD of ____ is used to prevent any closer movemtn of tube
    15 in
  14. 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  
  15. anything with the word screen or cathode means what
    • screen = means it produces light
    • cathode means it produces electrons
  16. what general technical fasters are used to increase brightness in fluoro
    high kvp low mA
  17. 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
  18. what is the second layer of the II
    what is this layer made of
    • photocathode layer
    • cesium & antimony compounds
  19. 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
  20. 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)
  21. 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
  22. 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
  23. the output phosphor screen is composed of
    zinc cadmium sulfide
  24. how else can the xray tech operate the the fluoro machine
    by a foot pedal (dead man type)
  25. 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