Brainscape's Knowledge GenomeTM


Top Flashcards (Certified)
All Flashcards

Terri > Spatial Resolution > Flashcards

Spatial Resolution Flashcards

1
Q

F/S recorded detail definition

A

The sharpness of the structural LINES as recorded in the radiographic image.

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

Digital radiography spatial resolution definition ASRT

A

The sharpness of the structural EDGES recorded in the image.

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

What effect will the following change
Have on recorded detail:
From 100 mA to 200 mA

A

Impacts visibility of detail only

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

What effect will the following change
Have on recorded detail:
Change from 0.01 sec to 0.005 sec

A

Impacts visibility of detail;

And increases sharpness if motion is an issue.

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

What effect will the following change
Have on recorded detail:
60 kVp to 50 kVp

A

No change to sharpness of detail (SR)

Only impacts visibility of detail

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

What effect will the following change
Have on recorded detail:
8:1 grid to no grid

A

No change to sharpness of detail.

Impacts visibility of detail

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

What effect will the following change
Have on recorded detail:
2” OID to 6” OID

A

⬇️ spatial resolution

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

What effect will the following change
Have on recorded detail:
Large focal spot to small focal spot

A

⬆️ spatial resolution

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

What effect will the following change
Have on recorded detail:
Patient is moving

A

⬇️ spatial resolution

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

What effect will the following change
Have on recorded detail:
1mAs to 2mAs without changing time

A

Impacts visibility of detail only

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

What effect will the following change
Have on recorded detail:
40” SID to 72” SID

A

Increases spatial resolution/sharpness of detail

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

Define Focal Spot

A

The area of the target from which X-rays are emitted.

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

The size of large focal spots

A

Range from 1.2 to 2.0 mm

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

Size of small focal spots

A

0.1mm to 1.0mm

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

Large focal spots are generally used for mA over

A

200-300

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

Define ACTUAL FOCAL SPOT

A

The area of bombardment on the target where X-rays are produced.

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

Define EFFECTIVE FOCAL SPOT

A

The area projected onto the patient and the IR. The size of the focal spot is identified here.

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

Define LINE FOCUS PRINCIPLE

A

A design feature whereby the anode is angled, so that the effective focal spot is smaller that the actual focal spot.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

What is the function of the line focus principle

A

Improve detail

Improve heat capacity

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

Diagnostic X-ray tubes have anode angles ranging from

A

5-17 degrees

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

What is the one disadvantage of the line focus principle?

A

The Heel Effect/Anode Heel Effect

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

Describe the Heel Effect

A

Because of the divergent beam, a portion of the useful beam, emitted towards the anode side of the tube is absorbed by the heel of the anode.
Thus there is reduced X-ray intensity on the anode side of the tube.
This difference can vary as much as 45%.
This can be useful when imaging body parts with uneven thickness. Positioning the cathode over the thicker part of the anatomy provides more uniform density.

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

Extra focal radiation results when

A

Electrons bounce off the focal spot and land on other areas of the target generating X-rays outside of the focal spot

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

Focal Spot Blooming is not constant. It broadens or blooms with: (3)

A
  1. Age and use
  2. Large mAs
  3. Decreasing kVp
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

How does large mAs influence fs blooming

A

Increase current to the cathode filament causes increased heat.
The hotter the filament, the larger the space charge, so the effective focal spot broadens. (Try to use lowest mA possible).

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

How does decreasing kVp influence f/s blooming

A

At lower kVps, the electrons flowing from the cathode to the anode tend to stray since the potential difference is not as great.
They hit a wider area of the anode and enlarge the effective focal spot.

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

Name Focal Spot QC tests

A
  1. Pinhole camera
  2. Resolution Test patterns: - star pattern resolution test
    - line pattern test
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
28
Q

The line-focus principle allows

A

High anode heating with small effective focal spots.

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

As the target angle decreases, what happens to the effective focal spot

A

Decreases

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

How can we purposely distort anatomy

A

Angle tube

Oblique pt

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

To minimize distortion we can

A

Put part parallel to IR

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

What feature of X-ray equipment helps us minimize distortion

A

Detent

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

Two types of distortion we use in X-ray

A

Elongation

Foreshortening

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

What does “distortion of position” mean

A

Where you place part under CR and angled.

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

How does a ⬇️ in OID effect MF

A

Decrease

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
36
Q

How does ⬆️SID effect MF

A

Decrease

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
37
Q

Spatial resolution means

A

Visibility and Sharpness

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

Factors that influence visibility

A 
Are not IR specific
Contrast 
Grid
Scatter
kVp
mAs
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
39
Q

Factors that influence Sharpness

A

IR
Physical factors
Geometric factors
Motion

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

How can we control the physical factors influencing sharpness

A

We need to control motion:

  1. Give good pt instruction
  2. Immobilization
  3. Short exposure time
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
41
Q

Visibility means the image is in

A

Diagnostically useful range; density and contrast

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
42
Q

Visibility factors for film screen IR

A
  1. Intensifying screen type and speed
  2. Film type and speed
  3. Processing time and temperature
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
43
Q

Digital IR visibility factors

A

Indirect IR
Direct IR
Processing

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
44
Q

Film screen IR sharpness factors

A

Intensifying screen type and speed
Film type and speed
F/s contact

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
45
Q

Digital IR sharpness factors

A

Indirect DR
Direct DR
Matrix size
Pixel size

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
46
Q

If the matrix size increases, the pixel size

A

Decreases

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
47
Q

⬆️matrix size gives

A

⬆️ resolution (sharpness only)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
48
Q

The type and speed of CR

Influence

A

Visibility and Sharpness

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
49
Q

How does the CR reader influence sharpness

A

The smaller the pinpoint of the laser, the better the sharpness

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
50
Q

Why does direct DR influence visibility

A

Because there are no phosphors, so no spreading of light.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
51
Q

3 geometric factors influencing sharpness

A

OID
SID
Focal spot size

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
52
Q

⬆️ OID with ? Sharpness

A

⬇️ sharpness

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
53
Q

⬇️ SID will ? Sharpness

A

⬆️ sharpness

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
54
Q

⬆️ Focal spot size ? Sharpness

A

⬇️ sharpness

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
55
Q

As focal spot decreases, what happens to geometric blur and to sharpness

A

Geometric blur decreases

Sharpness increases

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
56
Q

Which side of the image has more blur

A

The cathode side bc of the focal spot angle

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
57
Q

If there is inherent OID due to anatomy, we repair it by

A

Increasing SID

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
58
Q

Distortion

A

Misrepresentation of the size and shape of an object

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
59
Q

Magnification is desirable, when?

A

When we are looking for borders of tiny areas

Like in mammo for smooth or rough borders

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
60
Q

With size distortion, we increase OID, which will –resolution

A

Decrease

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
61
Q

Shape distortion is good when?

A

ImAging a 3-D object because the image is 2-D
We angle the tube
Or
Oblique part

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
62
Q

Can distortion be totally avoided?

A

No bc anatomy is 3-D and image is 2-D

63
Q

The further away the OID, how does it change the image size

A

Larger is the image size

64
Q

Magnification Factor

A

How much bigger the image is, compared to the object.

65
Q

3 qualities of an X-ray beam

A
  1. Heterogenous divergent beam- spreads out through distance.
  2. Heterogenous- made up of a variety of different energies
  3. Randomly distributed- the X-ray photons come down in a random pattern.
66
Q

Similar triangles mean

A

The 2 angles are the same size.

67
Q

If you want to magnify an object 2 times,

A

put it 1/2 way in the SID

68
Q

The decrease magnification:

A

Decrease OID

Increase SID

69
Q

Radiographic image quality

A

The accuracy that the anatomy being examined, is shown on the radiograph.

70
Q

High quality radiograph

A

Precisely reproduces structure and tissues.

71
Q

Spatial resolution

A

The ability to image small objects that have high subject contrast.
Such as bone-soft tissue interface
A breast micro calcification
Calcified lung nodule

72
Q

Screen-film radiography has—spatial resolution.

73
Q

Spatial resolution — as blur decreases

74
Q

Spatial resolution aka

A

Detail

Recorded detail

75
Q

Visibility of detail refers to

A

The ability to visualize recorded detail when image contrast and optical density (OD) are optimized.

76
Q

How does the speed of the image receptor influence spatial resolution

A

As IR speed increases:
Spatial resolution decreases
(High noise)

77
Q

⬇️ IR speed will – spatial resolution

A

⬆️ spatial resolution

78
Q

What are FILM FACTORS that affect f/s radiographic quality

A

Characteristic curve:

  1. Density
  2. Contrast
  3. Speed
  4. Latitude

Processing:

  1. Time
  2. Temperature
79
Q

What are GEOMETRIC FACTORS that affect f/s radiographic quality

A
  1. Distortion
  2. Magnification
  3. Blur
80
Q

What are SUBJECT FACTORS that affect f/s radiographic quality

A

Contrast:

  1. Thickness
  2. Density
  3. Atomic number

Motion

81
Q

As f/s development time ⬆️

A

Fog ⬆️
IR speed ⬆️
Spatial resolution ⬇️
Visibility ⬇️

82
Q

As f/s development temperature ⬆️

A

Fog⬆️
IR speed ⬆️
Visibility and spatial resolution ⬇️

83
Q

As OID ⬇️

A

Sharpness ⬆️

SR

84
Q

As SID ⬆️

A

Sharpness (SR) ⬆️

85
Q

3 geometric factors that affect radiographic quality

A

Magnification
Distortion
Focal-spot blur

86
Q

All images are larger than the object. This is a condition called

A

Magnification

87
Q

Quantitatively, magnification is expressed by the

A

Magnification factor

88
Q

Magnification Factor =

A 
ImAge Size/ Object Size
Or
SID / SOD
OR
IMAGE SIZE/OBJECT SIZE=SID/SOD
89
Q

2 factors that affect image magnification

90
Q

To minimize magnification

A

Large SID

small OID

91
Q

Shape distortion define

A

Unequal magnification of different portions of the same object

92
Q

3 conditions contribute to image distortion

A

Object: thickness
Position
Shape

93
Q

How does object thickness affect distortion

A

With a thick object, OID⬆️
So
Thick objects are more distorted.

94
Q

The image is not distorted if the object plane and the image plane are

95
Q

The image is not distorted if the object plane and the image plane are

96
Q

How do you increase the amount of foreshortening; extent of reduction in image size

A

Increase the inclination of angle will increase foreshortening

97
Q

What is the most important factor for determining spatial resolution

A

Focal-spot blur

98
Q

Focal spot blur is small when

A

The OID is small

99
Q

The focal-spot blur is small on the —side and large on the —side of the image.

A

Anode

Cathode

100
Q

How do you increase the amount of foreshortening; extent of reduction in image size

A

Increase the inclination of angle will increase foreshortening

101
Q

What is the most important factor for determining spatial resolution

A

Focal-spot blur

102
Q

Focal spot blur is small when

A

The OID is small

103
Q

The focal-spot blur is small on the —side and large on the —side of the image.

A

Anode

Cathode

104
Q

Reduce motion blur by

A

Restrict pt motion
Use shortest exposure
Time possible

105
Q

Small focal spots are used when?

A
  1. For fine detail
  2. For magnification studies
  3. For extremities
106
Q

Detail describes

A

The sharpness of appearance of small structures on the radiograph.

107
Q

Sharpness of image detail refers to

A

The structural lines or borders of tissues in the image and the amount of blur of the image.

108
Q

Factors that generally control the sharpness of image detail:3

A

Focal spot size
SID
OID

109
Q

Sharpness of image detail is influenced by

A

Type of intensifying screen
Presence
Of motion

110
Q

Key factors that provide the best visibility of image detail

A

Collimation
Grids
Other methods that prevent scatter

111
Q

Distortion can be minimized by 3

A

Proper tube alignment
Proper part alignment
Proper IR alignment

112
Q

What effect will the following change
Have on recorded detail:
2” OID to 6” OID

A

⬇️ spatial resolution

113
Q

Resolution

A

Measure of the ability of a system to image 2 separate objects and visually distinguish one from another

114
Q

In electronic imaging as digital image matrix size increases

A

Pixel size decreases

115
Q

Pixel depth is directly related to shades of gray, called?

And is measured in?

A

Dynamic range

Bits

116
Q

The greater the number of bits, the more?

A

Shades of gray

117
Q

Is pixel depth related to resolution

118
Q

A digital image is formed by a

A

Matrix of pixels in rows and columns

119
Q

Field of view

A

Used to describe how much of the patient is included in the matrix

120
Q

SID affects recorded detail in which way

A
  1. Directly related

2. As SID increase, recorded detail increases

121
Q

Why don’t we always use an large SID?

A

Because it would require a higher radiation dose to the patient.

122
Q

How does field size affect detail visibility

A

Because it decreases scatter radiation produced, it will result in improved detail visibility

123
Q

Which has better partial resolution, F/S or CR?

A

Film Screen has three times better spatial resolution than CR.

124
Q

4 acceptable ways to minimize motion unsharpness

A
  1. Use shortest possible exposure time
  2. Accurate patient instructions
  3. Suspended respiration
  4. Immobilization
125
Q

Subject / object unsharpness can result from ? Name 3

A
  1. Object shape does not coincide/conform with the shape of x-ray beam.
  2. Object plane is not parallel wth x-ray tube and / or IR
  3. Anatomic object is a distance from the IR
126
Q

As matrix size increase, spatial resolution

A

Improves / increases

127
Q

How does the size of the PSP affect spatial resolution?

A

Smaller phosphor size improves resolution, because there will be less spreading of light.

128
Q

How does the size of the scanner laser affect spatial resolution

A

The smaller the laser beam, the better the spatial resolution

129
Q

As FOV increases, how does it affect the pixels of a fixed matrix size? And affect the spatial resolution?

A

Size of each pixel increases.

The spatial resolution decreases.

130
Q

For the same FOV,spatial resolution will be improved using?

A

A larger matrix

131
Q

If matrix size increases, and fixed FOV, than pixel size will

A

Decrease, and better spatial resolution

132
Q 
All the following are related to recorded detail except:
mA
Focal spot size
SID
OID
133
Q

Focal Spot blur is greatest towards the —- end of the beam?

A

Cathode end

134
Q

Focal spot blur / geometric blur is caused by

A

Photons emerging from a large focal spot.

135
Q

Factors that determine recorded detail in digital imaging include? 3.

A
  1. Motion
  2. Geometric Factors (OID, SID, and focal spot size)
  3. Spatial resolution
136
Q

In analog systems, spatial resolution is related to the?

A

Speed of the system/ intensifying screen speed

137
Q

The spatial resolution of direct digital system is?

A

Fixed
Related to the detector element (DEL) size of the thin film transistor (TFT).
Smaller DEL SIZE, better resolution

138
Q

DEL size of 200 in general radiography provides a spatial resolution of

139
Q

A 100 speed intensifying screen system offers a spatial resolution of

140
Q

How is OID related to recorded detail?

A

Inversely

As OID increases the detail decreases; magnification increases

141
Q

In digital imaging as DEL sizes decreases, spatial resolution

142
Q

Recorded detail is inversely related to

  1. SID
  2. OID
  3. Part motion
A

OID

Part motion

143
Q

Does mAs affect recorded detail

144
Q

What are the geometric factors that influence recorded detail

A

Focal spot
OID
SID

145
Q

In film screen imaging spatial resolution is related to the

A

Speed of the imaging system / intensifying screen speed

146
Q

The spatial resolution of direct digital systems is related to

A

Detector element size of the thin film transistor

147
Q

When involuntary motion must be considered, the exposure time may be cut in half if the kilovoltage is?

A

Increased by 15%

148
Q

The greatest enemy of resolution

149
Q

Focal spot blur is related to

A

Focal spot size

150
Q

Which focal spot size produce less Blur and better resolution

A

Smaller focal spots

151
Q

What term is used to describe unsharp edges of tiny radiographic details

A

Geometric Blur

152
Q

Recorded detail can be improved by decreasing which:

  1. SID
  2. OID
  3. Part motion
A

OID

Part motion

153
Q

What units are used to express resolution

A

Line pairs per millimeter

Terri (8 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2025 Bold Learning Solutions. Terms and Conditions