Image Intensifier Flashcards

1
Q

What is fluoroscopy

A

Real time dynamic viewing of anatomic structures

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2
Q

Who invented the fluoroscope and in what year

A

Thomas Edison 1896

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3
Q

Who was Thomas Edison’s Assistant who was the first to die from Radiation and when

A

Clarence Dally

1904

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4
Q

Who is the father of x-rays and when was it invented

A

Wilhelm Roentgen Nov. 8th 1895

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5
Q

Who was the first person to have an x-ray

A

Anna Bertha Ludwig

wilhelm roentgen’s wife

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6
Q

Viewers had to wait 15-20 minutes in a dark room before fluoro exam, this is known as?

A

Dark Adaption

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7
Q

Who invented the red adaption goggles and when

A

Wilhelm Trendleenburg in 1916

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8
Q

What was the purpose of the red goggles

A

to sensitize the physicians eye prior to procedure while still allowing him to receive enough light to function normally.

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9
Q

Red goggles became obsolete with the invention of ____

A

Image Intensifiers

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10
Q

When were II and TV cameras invented

A

1950

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11
Q

What is the purpose of the Television camera

A

Allows radiologist to view images in a separate room away from radiation exposure

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12
Q

Name 3 types of fluoro equipment

A
  1. C-arm/ Fluoroscans
  2. Under table units
  3. Over table units
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13
Q

______ uses a solid-state radiation detector and an electronic processing with a computer monitor for display

A

Digital fluoroscopy

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14
Q

C arms are used in ____ clinic where as fluoroscans are used in ____ clinic.

A
  1. Pain clinic

2. Ortho

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15
Q

What is the role of the technologist during a fluoro exam

A
  1. Provide assistance to radiologist and pt. before , during and after exam
  2. Prep the room
  3. Prep the contrast
  4. Prep the patient
  5. Get hx. from pt.
  6. After care instructions to patient
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16
Q

Name 5 fluoro exams

A
  1. Esophagus
  2. Upper GI
  3. ERCP
  4. Angiograms
  5. Venogram
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17
Q

Where is it safe to stand during a fluoro exam

A

Behind the lead shield and behind the radiologist

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18
Q

It is safer when the tube is ____ the exam table

A

Under

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19
Q

The protective curtain contains how many mm of PB

A

at least . 25 mm PB

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20
Q

During a fluoro exam, scatter is dependent on what factors?

A
  1. kVp used
  2. Body part
  3. Thickness of part
  4. Time of exam
  5. Area exposed
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21
Q

When referring to Fluoroscopic scatter radiation, units are in:

A

mR/ hr or mGy/ hr

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22
Q

Time (hr) is an important unit in fluoroscopy exams. The ____ determines time for fluoroscopy “on” time.

A

operator

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23
Q

Scatter radiation from pt at 1 foot from table can be as high as

A

500 millirads/ hour

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24
Q

In fluoro, the x-ray output is directly proportional to ___.

A

the mA used

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25
Q

During image intensified fluoroscopy, tube currents range of:

A

.5-5 mA

usually 1-3 mA

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26
Q

True or False: Collimating the useful or primary x-ray beam to the area of clinical interest is optional ?

A

False : it is required by law

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27
Q

How is image quality improved in fluoro?

A

by reducing the size of the beam ( Well collimated)

28
Q

Filtration must be ____ mm AL eq. when x-ray tubes in fluoro operate at 126-160 kVp.

A

3 mm AL

29
Q

Why is filtration necessay?

A

To protect the pt.s skin from unnecessary radiation dose

30
Q

What does STD stand for

A

Source to table top distance

31
Q

What does TPD stand for

A

OR target to panel distance

32
Q

TPD should not be less than ____ inches and should be at least _____ inches

A
  1. 12”

2. 18” ( optimal for fluroro exams)

33
Q

How does moving the II away from the patient affect pt. dose

A

Increases pt. dose

only when the tube is fixed below the table

34
Q

The II serves as a ____ barrier and must be at least ____ mm of Pb equivalent for operating above 125 KVP.

A
  1. Primary protective barrier

2. 2 mm of Pb

35
Q

Fluoro exposure swiitch must be of the ____ type

A

dead man type

36
Q

Radiation dose to patient and operator is directly related to ____

A

duration (time) of the exposure

37
Q

The predetermined time limit may not exceed _____..

What is the primary purpose of this reset time?

A

5 minutes

  • Indicates total fluoro time,
  • Assists in protection from unnecessary exposure
38
Q

Lead aprons are available in what mm of PB

A

.25, 0.5 & 1.0 mm of Pb

39
Q

Lead gloves and thyroid shields are available in what mm of Pb

A

.25 and 0.5 mm of Pb

40
Q

What is the purpose of the the II

A

to brighten dim images of conventional fluoro to levels in which the human eye can perceive fine detail

41
Q

When was the first II imvented

A

mid 1930’s

42
Q

What are the 3 factors that influence visual ability

A
  1. Visual acuity
  2. Viewing Distance
  3. Integration time
43
Q

Define visual acuity

A

Ability to perceive fine detail

44
Q

Optimal viewing distances about _- to ___ inches

A

12-15 inches

45
Q

Time required for recognition of an image

A

.2 seconds

** longer time does not equal increased recognition***

46
Q

Describe rods

A
  • used in night (scotopic) vision
  • perceive only shades of gray
  • located on the periphery of retina
  • Poor visual acuity
47
Q

Describe cones

A
  • used in daylight (photopic) vision
  • Perceive color
  • Located in fovea centralis
  • visual acuity is 10 x more than scotopic vision
  • What we utilize in fluoroscopy
48
Q

Why should the room light be dim during a fluoro exam

A

to enhance visualization of black and white television images

49
Q

What is the main function of II

A

to convert photons to amplified light energy

50
Q

Describe the main component of II pathway

A
  1. INPUT PHOSPHOR: X-rays to light
  2. PHOTOCATHODE: Light to electrons
  3. ELECTROSTATIC FOCUSING LENSES: Steer those electrons
  4. ACCELERATING ANODE: Speed up those electrons
  5. OUTPUT PHOSPHOR: Electrons to light
51
Q

Photocathode converts visible light to electrons (photoelectrons) through

A

photoemission

52
Q

____ is electron emission that follows light stimulation.

A

photoemission

53
Q

The ability of the image intensifier to increase the illumination level of the image is called

A

brightness gain

54
Q

define brightness gain

A

ability of II to increase illumination level of the image

55
Q

The brightness gain is simply the product of ____ & ____.

A
  1. minification gain

2. Flux gain

56
Q

____ occurs as a result of the same number of electrons that were produced at the large input phosphor (screen) being compressed into the area of the small output phosphor (screen).

A

Minification gain

57
Q

What is the formula for MG ( minification gain)

A

MG =
(Input Diameter )2
_________________
(Output Diameter)2

58
Q

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

A

Flux gain

59
Q

What is the formula for Flux gain

A

FG =
# of output light photons
___________________
#of input x-ray photons

60
Q

Brightness gain can deteriorate or degrade as much as ___% per year due to the “aging” of the input and output screen phosphors.

A

10 %

— Brightness can be check measuring the Conversion factor

61
Q

What is the formula for CF ( conversion factor)

A

CF =
Intensity of output phosphor (measured in candelas/cd
_______________________
Input exposure rate millirads/second

62
Q

Most II are of ___ type

A

Multifield type

63
Q

What is the most popular trifield tube

A

25/17/12cm

diameter of the input phosphor of the II

64
Q

How does magnification occur in fluoro?

A

switch is made to the 17 cm mode which increases voltage to the electrostatic focusing lens

-this moves the focal point further away from output phosphor

65
Q

Magnification results in:

A
  1. Better spatial resolution
  2. Better contrast resolution
  3. Increase in pt. dose
66
Q

What is the formula to calculate pt. dose after magnification ?

A

(Normal mode size)2
_____________
(Mag mode size)2