Principles of fluroscopy equipment and function Flashcards

1
Q

name 4 reasons why fluoroscopy would be used

A

1) need for dynamic imaging
2) Diagnosis
3) Asses function
4) Guide intervention

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2
Q

Name the three configurations that the fluoroscopy equipment can be

A

1) under-couch tube
2) over-couch tube
3) C-arm

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3
Q

Name 3 advantages for the under-couch tube

A

1) lead skirt to reduce scatter
2) able to reduce object to detector distance as much as possible
3) Conventionally used for angiography

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4
Q

name 5 disadvantages to the under-couch tube

A

1) mostly operated from the tube itself
2) higher dose to user due to tube position
3) more enclosed for the patient
4) limited access to the patient
5) unable to angle the tube

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5
Q

name 5 advantages to the over-couch tube

A

1) usually operated form behind the control panel
2) able to lower closer to the floor
3) easy to use ad standard tube for table work
4) easy to access the patient
5) lower dose

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6
Q

name 4 advantages for the C-arm

A

1) can be either over-couch or under-couch
2) mobile C-arm can be used in theatre
3) patient doesn’t need to move as much
4) Replacing over and under-couch tubes

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7
Q

`Name the disadvantage of the C-arm

A

1)need to be aware where the x-ray tube is pointing

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8
Q

what 7 things make up the image intensifier?

A

1) attenuated x-ray beam
2) input phosphor
3) photocathode
4) Focusing electrodes
5) Output phosphor
6) Video camera
7) TV

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9
Q

what does the input phosphor do

A

converts x-ray photons into fluorescent light

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10
Q

what is the input phosphor made of

A

caesium iodide

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11
Q

what is the input phosphor coupled to

A

the photocathode

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12
Q

what does the input phosphor do to the thickness of the phosphor

A

increases the thickness- therefore more photons absorbed and converted into light

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13
Q

what is the photocathode made of

A

caesium antimony

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14
Q

what does the photocathode to

A

converts light into electrons

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15
Q

What two things happen in the vacuum tube

A

1) electrons are accelerated from the cathode to the anode

2) then focused down in size by focusing electrodes

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16
Q

what is the output phosphor made of

A

silver activated zinc-cadmium sulphide

17
Q

what happens in the output phosphor

A

electrons hit the output phosphor and are turned into green light

18
Q

how many light photons are there in the output phosphor per incident electron

A

2,000

19
Q

name the two reasons why the resultant image is brighter and smaller

A

1) Flux gain

2) minification gain

20
Q

what is flux gain

A

for every light photon generated at the input phosphor there are (x100) light photons at the output phosphor

21
Q

what is minification gain

A

same photons but in a smaller area

22
Q

23cm II has output window of

A

1.5-6cm

23
Q

what is the minification gain of 23cm II

A

120

24
Q

what is the purpose of the automated brightness control (3 points)

A

1) it is important that fluoroscopy procedures follow the ALARP principle
2) Brightness will change with the part of the body- some areas are more radiolucent than others
3) A monitoring device samples the brightness of the image output and adjusts mA or kV accordingly

25
Q

name 5 examples of procedures that use fluoroscopy

A

1) GI studies
2) angiography
3) ERCP
4) HSG
5) Theatre

26
Q

name three types of GI studies

A

1) barium enema
2) barium swallow
3) water soluble studies

27
Q

name two types of theatre

A

1) orthopaedic

2) Pacing theatre