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Exposures ll (mine) > Chapter 33: Fluoroscopy > Flashcards

Chapter 33: Fluoroscopy Flashcards

1
Q

Dynamic movement of an image?

A

Fluoro

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2
Q

KUB is considered what type of image?

A

static image

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3
Q

Active diagnosis in fluoro is in control of who?

A

domain of radiologist

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4
Q

What can the radiologist see when doing fluoro?

A

Visibly watching barium go through the esophagus to the stomach

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4
Q

who was the fluoroscope invented by and when?

A

Invented by Thomas Edison in 1896

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5
Q

When Thomas Edison invented fluoro how were the machines back then?

A

Consisted of x-ray tube and hand-held fluoroscopic screen that was very high exposure directly into eyes, neck and hands

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6
Q

Who was the first person to introduce radiation protection and was also a dentist?

A

William Rollins

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7
Q

Where is the x-ray tube and image intensifier located in fluoro?

A

x-ray tube is below and image intensifier is on top

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8
Q

dynamic imaging modality designed to observe moving structures in the body

A

Fluoroscopy

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9
Q

When was the image intensification (ii) developed?

A

in 1948

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10
Q

Fluoro is considered what two types?

A

CR in the OR + Fluoro with barium

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11
Q

Digital fluoro deals with what?
-predominated by 2005

A

-TFT matrices
-Post processing capabilities

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12
Q

What are the different pieces of equipment involved with fluoro?

A

-Fluoroscopic screen
-mirrors for viewing (obsolete)
-image intensification (video camera and monitor)

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13
Q

Electronic devise mounted above the table and patient and permantely attached to the x-ray tube

A

Image Intensifier

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14
Q

Purpose of the image intensification?

A

increase brightness of fluoroscopic images by thousands (8,000 times)

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15
Q

What did mirror optics for viewing replaced with?

A

replaced with closed circuit TV systems

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16
Q

What is the last image hold for?

A
  • a type of radiation protection for the patient
  • decrease dose
  • the last image is up on the monitor
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17
Q

fluoroscopic uses for functional studies:

A

o Gastrointestinal (GI) tract studies
o Angiograms
o Line placements
o Orthopedic surgeries
o IVU

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18
Q

Audible timer, radiation protection that beeps saying patient has been in fluoro for 5 minutes?

A

5 minute timer

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19
Q

In order to active fluoro what must you do?

A

You have to apply pressure whether is up on the tower or the paddle

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20
Q

When applying pressure is considered what?

A

dead man switch

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21
Q

A dead man switch is also considered

A

another type of radiation protection

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22
Q

Should fluoro be used to preview patient’s radiographic position?

A

NO!!!

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23
Q

Where should the patient be shielded for fluoro?

A

from behind the patient since the x-ray tube is below

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24
Q

Since you are using a high time in fluoro what happens to your mA?

A

you are using a low mA
-reciprocity law

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24
Q

In what directions can the image intesnifier move?

A

It can move up and down, side to side
-moves in all directions

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25
Q

Why does the image intensifier only go down a certain amount?

A

Is another type of radiation protection

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26
Q

Your beam in fluoro is still what?

A

the beam is geometry

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27
Q

What is the mA range for the fluoroscopic x-ray tube

A

0.5 to 5.0 mA

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28
Q

What is SOD?

A

Source to object distance

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29
Q

What is the source for SOD for fluoro?

A

The source is the x-ray tube

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30
Q

What is the object for SOD in fluoro?

A

the object is the patient

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31
Q

What is the minimum SOD in fixed fluoroscopic equipment (fluoro room)?

A

15 inches or 38 cm

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32
Q

What is 15 inches converted to centimeters?

A

38 cm

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33
Q

What is the minimum SOD in mobile fluoro examination (C-arm)

A

12 inches or 30 cm

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34
Q

What is 12 inches in cm?

A

30 cm

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35
Q

What is known as the foot switch

A

deadman switch

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36
Q

Can you collimate for fluoro?

A

Yes is known as your shutters also your patient protection

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37
Q

components of the image intensifier: correct order

A

-output phospher
-anode
-electrostatic lenses
-photocathode
-input phospher

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38
Q

How do your eyes adjust in fluoro?

A

-cones
-rods

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39
Q

Help you see in bright lights, photopic

A

Cones

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40
Q

Helps you see in low lights, scotopic

A

Rods

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41
Q

Supports the patient and can be changed from a horizontal position to a vertical position
- Equipped with a movable footboard

A

X-ray table

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42
Q

What is the function of input phosphor?

A

Collecting x-ray photons and converting it to light because there is cesium iodide

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42
Q

Image intnsifier starts off from the x-ray table to patient by:

A

Incoming photons are coming up (exit radiation) to the input phosphor

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43
Q

Input phospher is coated with what?

A

Cesium iodide

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43
Q

*concave surface
*approx. 10-35 cm in diameter
*coated with cesium iodide
* converts xray photons to light photons

A

input phosphor

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44
Q

What two things are concave in shape?

A

Input phosphor and photocathode meaning they could fit on top of each other

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44
Q

converts light photons to electrons ; called photoemission

A

Photocathode

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45
Q

Mimics the pattern of light demonstrating the anatomy of the patient emitted by the input phosphor (latent image)

A

Photocathode

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45
Q

made of cesium antimony

A

Photocathode

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46
Q

Narrowing of electrons
- has a negative charge
-slight kvp applied to help keep moving the beam
-acceleration of electrons

A

Electrostatic lenses

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47
Q

-located along the inside of the image intensifier
-charged with a low voltage of 25-35 kvp
-function: accelerate and focus the electrons towards the output phosphor
-focal point: location where the electrons cross as they travel from the photocathode to the anode; changes position when intensifier is operated in normal vs. magnification mode

A

Electrostatic lenses

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48
Q

Electrons pass through the hole in

A

Anode

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49
Q

Do the electrons interact with the anode?

A

No!!

50
Q

Why is the anode there?

A

to capture the attraction of negative to positive

50
Q

*positively charged end of the image intensifier
*attracts the photoelectrons due to electrostatic charge
*contains the output phosphor at end

A

Anode

50
Q

When electrons pass through the anode where are they going?

A

to the output phosphor

51
Q

After electron passes through the anode it is then converted to light in?

A

Output phosphor

52
Q

The after the electrons is converted to light in the output phospher what happens next?

A

Is then converted to your analog-digital-converter which goes on the monitor your manifest image

53
Q

Made of zinc cadmium sulfide

A

Output phosphor

53
Q

-Made of zinc cadmium sulfide
-approximately 2.5-5.0 cm in diameter
-Function: converts photoelectrons to visible light

A

Output phosphor

54
Q

The output phospher is coated with a thin aluminum coating because?

A

To help prevent light leaking back into the intensifier

55
Q

How much lead is in the bucky slot cover?

A

0.25 mm of lead

56
Q

How much lead in the curtain (lead curtain) (lead drape)?

A

0.25 mm of lead

57
Q

How much does a regular lead apron have? recommend lead for an apron

A

0.25 mm of lead

58
Q

What is the recommend lead for a lead apron for fluoro?

A

0.5 mm of lead

58
Q

In fluoro what comes into place to keep you safe?

A

time, distance, and shielding
-jump behind the radiologist

58
Q

The closer you are

A

the more scatter you are going to get

58
Q

If you don’t have a wrap around apron what should you not do?

A

Never turn your back to the beam
-walk backwards

59
Q

is input or output bigger

A

Input is bigger

60
Q

Accelerate and focus electron pattern across tube
to anode
*primary source of brightness gain (due to acceleration of electron stream and increased kinetic energy)

A

Electrostatic lenses

61
Q

what does greater voltage to electrostatic lenses do

A

-increases acceleration of electrons
-shifts focal point away from anode

61
Q

made of zinc cadmium
sulfide
-glass fluorescent screen

A

Output phosphor

61
Q

Image intensification tube components:

A

-input screen and photocathode
-electrostatic lenses
-magnification tubes
-anode and output screen
-total brightness gain (minification gain * flux gain)

62
Q

image intensification was introduced in 1948. What was modified.

A

-higher visual acuity
-uses photopic vision (cones)
-reduced fluoroscopic dose

63
Q

hole in center allows electrons to pass through to output screen

A

Anode

63
Q

Early fluoroscopes required imaging to be completed in?
-reliance on?

A

completed in total darkness
-relied on scotopic vision (rod vision)

64
Q

When you go to magmode what are you increasing?

A

You are increasing your patient dose

65
Q

What is your advantage of going into magmode (magnification)?

A

increase spatial resolution

65
Q

What is your disadvantge of magmode (magnification)?

A

increasing patient dose

65
Q

distortion in fluoro is called?

A

Vignetting

65
Q

because of concave shape you get a distortion called

A

pincushion distortion

66
Q

When you go to magmode you are only focus where?

A

You are focus on the center
-getting rid of outer edge distortion

66
Q

When you go into magmode what happens to your focal point?

A

It changes

66
Q

When you go into magmode your focal point goes closer to what?

A

goes closer to your input phosphor

66
Q

In the normal mode is closer to what?

A

closer to output phosphor

67
Q

Magnification =

A

input screen diameter
over
diameter of input screen used during magnification

-smaller during magmode (surface area)

67
Q

You want everything to go forward because if not what happens?

A

You get backscatter of light which leads to distortion of the image

67
Q

minification gain x flux gain is known as your?

A

Total brightness gain

68
Q

Total brightness gain =

A

minification gain x flux gain

68
Q

measurement of increased image intensity achieved by image intensifier tube

A

total brightness gain

69
Q

In order to get your total brightness gain you need to get what?

A

the minification gain and the flux gain

70
Q

Output light intensity is measured in

A

candela

70
Q

Is known as your input screen diameter squared over your output screen diameter squared

A

minification gain

71
Q

Results from concentration of large electron volume from input phosphor, being focused down onto small area of output phosphor

A

Minification gain

71
Q

helps increase that brightness

A

minification gain

72
Q

minification gain =

A

input screen diameter ^2/output screen diameter^2

73
Q

Measurement of conversion efficiency of output screen
ex. one electron strikes output screen
-50 light photons emitted per electron striking output phosphor
-flug gain 50

A

flux gain

74
Q

efficiency of image intensifier

A

flux gain

75
Q

Increased brightness due to same number of light photons being concentrated on a smaller area

A

Minification gain

75
Q

flux gain =

A

output photons over your input photons

76
Q

electrons to light come into play

A

flux gain

77
Q

Maintains density (brightness) and contrast to compensate for different body thickness

A

Automatic Brightness Control (ABC)

78
Q

unit for the measurement of light intensity or luminance

A

candela

79
Q

Which is better?
Fluoroscopic or static radiography resolution

A

Static radiography

80
Q

Edges of image intensifier have lower resolution due to:

A

Vignetting

80
Q

Image quality affected by:

A

-contrast
-resolution
-distortion
-quantum mottle

81
Q

contrast is affected by:

A

-scatter radiation
-light scatter (penumbra)

81
Q

Controlled by amplitude of video signal

A

contrast

82
Q

the more scatter you have

A

the lesser the contrast

83
Q

contrast uses

A

window width and filtering algorithm

84
Q

unsharpness

A

penumbra

84
Q

sharpness

A

umbra

85
Q

differences in density between different body parts

A

contrast

86
Q

Resolution varies depending on geometric Factors:

A

SID, OID, minification gain
longer sid, smaller oid

86
Q

blotchy, grainy appearance
-caused by too little exposure
-most commonly remedied by increases mA

A

Quantum mottle

87
Q

-affected by same parameters as static radiography (primarily oid)
- geometric problems in shape of image intensifier input screen
-concave shape helps reduce distortion
-vignetting or pincushion effect
-not a problem with TFT matrices
-uniform resolution across flat panel detector array

A

Size distortion

88
Q

Improved by increasing total exposure to intensifier input phosphor
-increase mA
-reduce distance between patient and image intensifier
-increase kvp

A

Quantum mottle

89
Q

digital fluoroscopic system use

A

flat panel displays

90
Q

What is the difference with flat panel fluoroscopy ?

A

-No intensifier tube
-no vignetting
-no dose increase in mag mode

90
Q

Most common viewing system:

A

Video
-video camera attched to output phosphor
-fluoro video camera uses CCD
-display monitor for viewing

91
Q

Highest energy scatter

A

-90 degrees angle to incident beam
- same level as radiographer / radiologists gonads

92
Q

what generator is used for digital fluoroscopy

A

High power generator

93
Q

Newer systems are placing ii with

A

amorphos silicon (indirect)

93
Q

in digital, Image intensifier output screen coupled to :

A

TFT (holding your laten image)

93
Q

what is used in digital fluoroscopy to lower noise

A

pixel binning

94
Q

in digital fluoroscopy, what is connected to each pixel

A

Photodiodes

95
Q

Use C C D to generate electronic signal
Signal sent to A D C
Allows for post-processing and electronic storage and distribution
Last image hold function
Post-exposure image processing

A

digital fluoroscopy

95
Q

populary for surgery, er, orthopedic studies
operates the same as stationary units
-pary particular attention to radiation dose when using mobile fluoroscopy

A

C-arm units

96
Q

patient protection for fluoroscopy

A

-audible alarm at 5 minutes
-same rules for collimation
-last image hold

97
Q

What is the mR for xray tube and fluoro

A

-X- ray tube 100 mR
- Fluoro tube 10 mR per min

98
Q

how often should the fluoro system and lead aprons be checked?

A

-the fluoro system should be checked every 6 months
-the lead gowns should be checked yearly

99
Q

how much aluminum for filtration for fluoro

A

2.5 mm of aluminum

100
Q

total number of light photons produced by each electron

A

flux gain

101
Q

the ratio of light photons at the output phosphor divided by the number of input photons

A

flux gain

Exposures ll (mine) (9 decks)

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