Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

RT 210 > 5. Intensifying Screens > Flashcards

5. Intensifying Screens Flashcards

1
Q

device found in radiographic cassettes that contains phosphors to convert x-ray energy into light, which then exposes the radiographic film

A

Intensifying Screen

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

Intensifying Screen layers

A
  1. Protective layer
  2. Phosphor layer
  3. Reflecting or Absorbing layer
  4. Base
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

10-20 micrometer thick

A

Protective Coating

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

protects the screen from abrasion, helps eliminate static, and provides surface for cleaning

A

Protective Coating

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

active layer

A

Phosphor layer

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

50-300 micrometer

A

Phosphor layer

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Phosphor materials

A

calcium tungstate, zinc sulfide, barium lead sulfate, and rare earth oxysulfides such as gadolinium, lanthanum, and yttrium

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

approx. 25 micrometer thick made of magnesium oxide or titanium dioxide

A

Reflective layer

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

furthest from the film

A

Base

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

approx. 1 mm thick, made of polyester

A

Base

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

serves as mechanical support for active phosphor layer

A

Base

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

intensifies x-rays reducing radiation dose

A

Intensifying screen

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

emission of visible light

A

Luminescence

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

emission of light during stimulation

A

Fluorescence

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

afterglow

A

Phosphorescence

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

emission of light after stimulation

A

Phosphorescence

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

identified by relative speed ranging from 50 (slow, detail) to 1200 (very fast)

A

Screen speed

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

Characteristic Type of Phosphor

A
  • Color of emission
  • Approximate speed
  • Intensification factor
  • Spatial resolution (lp/mm)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

Typical Radiographic Intensifying Screens

A
  • Calcium Tungstate

- Oxysulfides and Oxybromides of Y, La, Gd

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

La

A

Lanthanum (57)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

Y

A

Yttrium (39)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

Gd

A

Gadolinium (64)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

Color of emission (Calcium Tungstate)

A

Blue

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

Color of emission (Oxysulfides and Oxybromides of Y, La, Gd)

A

Green or blue

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

Approximate speed (Calcium Tungstate)

A

50-200

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
26
Q

Approximate speed (Oxysulfides and Oxybromides of Y, La, Gd)

A

80-1200

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
27
Q

Intensification factor (Calcium Tungstate)

A

20-100

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
28
Q

Intensification factor (Oxysulfides and Oxybromides of Y, La, Gd)

A

40-400

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
29
Q

Spatial resolution in lp/mm (Calcium Tungstate)

A

8-15

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
30
Q

Spatial resolution in lp/mm (Oxysulfides and Oxybromides of Y, La, Gd)

A

8-15

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
31
Q

Intensification Factor

A

IF = Exposure required without screen/ Exposure required with screens

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
32
Q

ratio of the exposure required to produce the same OD with a screen to the exposure required to produce and OD without a screen

A

Intensification Factor

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
33
Q

the relationship between intensification factor and entrance skin exposure

A

inversely proportional

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
34
Q

the _____ the ESE (patient dose), the ____ IF

A

larger ESE,

smaller IF

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
35
Q

uncontrollable factors affecting speed

A
  • Phosphor Composition
  • Phosphor Thickness
  • Reflective Layer
  • Dye
  • Crystal Size
  • Concentration of Phosphor Crystals
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
36
Q

controllable factors affecting speed

A
  • Radiation Quality
  • Image Processing
  • Temperature
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
37
Q

rare earth phosphors efficiently convert x-rays into usable light

A

Phosphor Composition

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
38
Q

the thicker the phosphor layer, the _____ is the detective quantum effiecient

A

higher

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
39
Q

have thick phosphor layers

A

High-speed screens

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
40
Q

have thin phosphor layers

A

Fine-detailed screens

41
Q

increases screen speed but also increases image blur

A

Reflective layer

42
Q

control the spread of light

A

Dye

43
Q

improve spatial resolution but reduce speed

A

Dye

44
Q

the larger the phosphor (crystal), the _____ the light produced

A

greater

45
Q

are approx. 1/2 of the crystals of high-speed screens

A

crystals of detail screens

46
Q

results in higher screen speed

A

higher crystal concentration

47
Q

as x-ray tube potential is increased the IF _____

A

increase

48
Q

excessive developing time for screen-film results in ____ IF

A

lower

49
Q

IF is ____ at high temperatures

A

lower

50
Q

deterioration of the radiographic image; speckled background that reduces image contrast

A

Image noise

51
Q

is a measurement of the efficiency of an image receptor in converting the x-ray exposure it receives to quality radiographic image

A

Detective Quantum Efficiency

52
Q

refers to the ability of the screen to absorb the incident x-ray photons

A

Absorption Efficiency

53
Q

describes how well the screen phosphor takes these x-ray photons and converts them to visible light

A

Conversion Efficiency

54
Q

term used to evaluate the accuracy of the recorded anatomic structural lines

A

Spatial Resolution

55
Q

refers to the smallest object that can be detected in an image

A

Spatial Resolution

56
Q

the ability of a radiographic image to demonstrate sharp lines

A

Spatial Resolution

57
Q

limiter by focal spot size

A

Spatial Resolution

58
Q

measured through line-pair test pattern, expressed by the number of lp/mm

A

Spatial Resolution

59
Q

using intensifying screens results to a _____ picture

A

blurry

60
Q

lp/mm of Direct exposure

A

50 lp/mm

61
Q

Increase IF, _____ Spatial resolution

A

decreases

62
Q

term used to describe the ability of an imaging receptor to distinguish between objects having similar subject contrast

A

Contrast Resolution

63
Q

rigid holder that contains the film and radiographic intensifying screens

A

Cassette

64
Q

Cassette layers

A
  1. Front cover (with low atomic number)
  2. Front and Back Screens
  3. Compression Device
  4. Back cover (with high atomic number)
65
Q

absorbs approx. half the number of x-rays

A

Carbon Fiber

66
Q

reduces patient exposure, longer x-ray tube life

A

Carbon Fiber

67
Q

emits light in the violet-to-blue region

A

Calcium Tungstate Screen (CaWO4)

68
Q

principally gadolinium, lanthanum, yttrium

A

Rare Earth Screens

69
Q

have the advantage of speed

A

Rare Earth Screens

70
Q

increased DQE and CE (Conversion Efficiency)

A

Rare Earth Screens

71
Q

refers to the color of light produced by a particular intensifying screen

A

Spectral Emission

72
Q

refers to correctly matching the color sensitivity of the film to the color emission of the intensifying screen

A

Spectral Matching

73
Q

Care of Screens

A
  1. Do not slide film into a cassette
  2. Do not dig the film out of the cassette
  3. Do not leave the cassette open
  4. Clean screens periodically
  5. Check and maintain good screen-film contact
74
Q

plastic that protects the phosphor

A

Protective layer

75
Q

absorbs radiation and converts it to light

A

Phosphor layer

76
Q

reflects light toward the film

A

Reflecting layer

77
Q

absorbs light directed toward it

A

Absorbing layer

78
Q

provides support and stability for the phosphor layer

A

Base

79
Q

The desired type of luminescence

in imaging is

A

Fluorescence

80
Q

refers to the ability of phosphors to emit visible light

only while exposed to x-rays (with little or no afterglow)

A

Fluorescence

81
Q

An undesired type of luminescence is

A

Phosphorescence

82
Q

is the emission of light after x-ray exposure has terminated

A

Phosphorescence

83
Q

causes unwanted exposure to the film

A

Phosphorescence or afterglow

84
Q

As screen speed ______, recorded detail ______

A

increases (s),

decreases (r)

85
Q

the capability of a screen to produce visible light is called

A

Screen speed

86
Q

increase screen speed and decrease recorded detail

A

Reflective layer

87
Q

decrease screen speed and increase recorded

detail

A

Light-absorbing layer or Light-absorbing

dyes

88
Q

light-absorbing layer or light-absorbing

dyes

A

Isotropic emission

89
Q

Any material that emits light in response to some outside stimulation is called a

A

Phosphor

90
Q

Higher conversion efficiency results in _______

noise

A

increased

91
Q

Image Detail =

A

Image Detail = Spatial Resolution + Contrast

Resolution

92
Q

The unaided eye can resolve about ____ lp/mm

A

10

93
Q

Spatial resolution improves with _____ phosphor crystals and _____ phosphor layers

A

smaller,

thinner

94
Q

Increase phosphor thickness, ______ spatial resolution

A

decrease

95
Q

Increase crystal size, ______ spatial resolution

A

decrease

96
Q

Increase speed screen, ______ patient dose

A

decrease

97
Q

The term rare earth describes those elements of group ____ in the periodic table

A

IIIa

98
Q

These elements are transitional metals that are scarce in nature.

A

Rare earth

99
Q

One advantage of the use of these commercial

preparations is that they often contain ______ compounds, which can be helpful

A

antistatic

RT 210 (9 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions