26-29 Flashcards
(124 cards)
1
Q
Photographic properties make the _____ of an image.
A
Detail
2
Q
What are the 2 photographic properties?
A
IR exposure
Contrast
3
Q
Without IR exposure and contrast
A
We would never be able to see am X-ray
4
Q
How light or how dark we make our final image is known as
A
Brightness
5
Q
Which post processing function controls brightness
A
Window Level
6
Q
Where does contrast come from?
A
LUTS
7
Q
Is contrast a post processing feature or pre processsing?
A
Pre-processing
8
Q
The best way to evaluate an image to see if it contains good IR exposure is by
A
Checking EI/DI values
9
Q
Where does IR exposure come from?
A
mAs and Contrast
10
Q
Too many photons striking the IR results in
A
Overexposure
11
Q
A _______ image will appear too dark
A
Overexposed
12
Q
It is better to ________ than to _______ because we can post process.
A
Overexpose
Underexpose
13
Q
A _____ image will appear too light.
A
Underexposed
14
Q
When the IR did not receive enough photons, it has been _______.
A
Underexposed
15
Q
mAs is ________ proportional to IR exposure.
A
Directly
16
Q
If mAs is increased, what will happen to the IR exposure
A
An increase
17
Q
In order to see a visible difference between 2 images, the mAs factor must have a minimum ______ change.
A
25%-35%
18
Q
When adjusting mAs, adjustments should be made in increments of
A
Doubles or halves
19
Q
An increase in kV will cause the IR exposure to
A
Increase
20
Q
____ alters the intensity of the beam reaching the IR.
A
kVp
21
Q
The target of the tube is the
A
Anode
22
Q
A 15% increase in kVp will _____ the IR exposure.
A
Double
23
Q
Single phase = _____% ripple
A
100
24
Q
Three phase = ______% ripple
A
4-14
25
High frequency = ______ ripple
1%
26
The generator type we want to use is
High frequency
27
FSS does what to IR exposure?
No effect
28
Which side of the tube does the anode heel effect alter the beam?
Cathode side
29
An increase in SID causes IR exposure to
Decrease
30
If SID is increased, what should we do to maintain IR exposure
Increase mAs (double)
31
A decrease in SID causes IR exposure to
Increase
32
If SID is decreased, what needs to be done to maintain IR exposure?
Decrease mAs (half it)
33
When dealing with intensity and distance, you’re dealing with the
Inverse square law
34
If kVp increases, scatter_______
Increases
35
An increase in OID, causes IR exposure to
Decrease
36
Where is filtration located?
In the tube
37
An increase to filtration cause IR exposure to
Decrease
38
What does beam restriction do?
Reduces the total number of photons available, which reduces scatter.
39
What does beam restrictions do to IR exposure?
Decreases it
40
An increase in Gris ratio causes IR exposure to
Decrease
41
_______ gives us anatomical detail
Contrast
42
Contrast ranges from
Black to white
43
The post processing function that controls contrast is
Window width
44
______ contrast has few shades of gray.
High
45
____ contrast is long scaled and has _____ shades of gray.
Low
Many
46
_____ is the primary controller of subject contrast,.
kVp
47
Range of differences in the intensity of the X-ray beam after it has been attenuated by the subject
Subject contrast
48
A _____ in field size means you’re opening up the collimators and will ____ IR exposure, causing a _____ in subject contrast.
Increase
Increase
Decrease
49
Can subject contrast be improved by post processing?
No
50
A decrease in IR exposure will cause a ____ to subject contrast
Increase
51
Does kVp effect subject contrast?
Yes
52
An increase in mAs causes contrast to
Increase
53
If filtration increases, contrast will
Decrease
54
A decrease in collimation is the same as saying
Opening collimation
55
An increase in collimation is the same as
Closing collimation
56
A decrease in collimation causes contrast to
Decrease
57
An increase in part size will cause contrast to
Decrease
58
Which of the following can impact the remnant signal?
1. Tissue density
2.pathology
3.beam restriction
1,2, and 3
59
Which of the following devices is used to overcome severe variation in patient anatomy or tissue density, providing more uniform receptor exposure?
Compensating filter
60
In digital imaging, kilovoltage selection has an effect on
1. Photon energy
2. Penetration
3. Image contrast
1 and 2
61
Increasing the technique factor kVp will have what effect on scatter production
Increase production
62
Scatter _______ IR exposure
Increases
63
Increasing IR exposure means to make the image
Darker
64
Subject contrast comes from the
Patient
65
If anatomic details are not recorded on the image, then the IR has been
Underexposed
66
Range of brightness levels and how they are displayed on the monitor is called
Dynamic range
67
The use of filtration devices will cause an/a __________ in IR exposure.
Decrease
68
True or false: Subject contrast that is underexposed can be improved by post-processing algorithms.
False
69
The filament and focusing cup are found on the __________ side of the x-ray tube.
Cathode
70
Post-processing can make an image that is __________ acceptable for interpretation.
Overexposed
71
LUT's is what determines image
Contrast
72
Which focal spot is projected out of the tube toward the object being radiographed.
Effective
73
The primary function of x-ray beam filtration is to
Reduce patient skin dose
74
What are the 2 geometric properties?
Spatial resolution
Distortion
75
How do we measure spatial resolution?
Line pairs per mm on the test tool
76
Degree of geometric sharpness or accuracy of the structural lines actually recorded in the image
Spatial resolution
77
Geometric properties control
Detail
78
Photographic properties control
Visibility of detail
79
We want a ______ matrix with ____ pixels to get good spatial resolution
Large
Small
80
High frequency spatial resolution has ____ wavelengths and _____ contrast
Shorter
High
81
QC testing are types of _____ test tools to make sure we’re getting good detail on our images
Resolution
82
What are the types of QC testing
Point spread
Line spread
Edge spread
83
We want an MTF of
1
84
Low signal and high noise gives us
Bad detail
85
CNR stands for
Contrast to noise ratio
86
Where does Nyquist Criterion happen
Within the system
87
Takes the data from the pixels and samples the signals twice from each cycle to make sure nothing was missed
Nyquist Criterion
88
When the Nyquist Criterion doesn’t get sampled twice
Aliasing
89
Detail is affected by
SID
OID
SOD
90
If SID increases, spatial resolution _______
Increases
91
We want a ____ OID to increase spatial resolution
Short
92
An increase to SOD will cause a _____ to spatial resolution
Increase
93
The main controller of detail is
FSS
94
What controls penumbra
FSS
95
The _____ penumbra, the better the resolution
Less
96
A smaller FSS will give us _____ penumbra
Less
97
What surrounds the Umbra
Penumbra
98
A long SID gives us _____ penumbra
Less
99
Less penumbra gives us _____ detail.
Greater
100
The smaller the pixels the _____ the detail
Better
101
Misrepresentation of the size of shape of the structure being examined
Distortion
102
Magnification is controlled by
SID/OID
103
The greater the SID the ____ the magnification
Smaller
104
Objects _____ from the IR will be magnified
Further
105
Magnification factor is
SID divided by SOD
106
What are the 2 types of shape distortion
Elongation
Foreshortening
107
Elongation makes the object look
Longer than what it is
108
Foreshortening makes the object look
Shorter than what it is
109
Poor alignment of the part causes
Foreshortening
110
Poor alignment of the tube and/or IR causes
Elongation
111
Angulation of the tube will always change
SID
112
An increased SID will cause magnification ton
Decrease
113
__________ will occur with central ray and IR alignment issues.
Elongation
114
In digital imaging, thin film transistor (TFT) and detector element (DEL) size is related to
Spatial resolution
115
An increase in patient thickness __________ spatial resolution
Decreases
116
Sharpness/resolution is ________ related to OID.
Inversely
117
An MTF of 1.0 represents a signal of extremely ______ fidelity
High
118
Misalignment of the tube-part-IR relationship results in
Shape distortion
119
The best method to reduce patient motion
Communication
120
The electronic term used to describe anything that interferes with visualization of the x-ray image is
Noise
121
Which focal spot size will create a larger penumbra?
Large FSS
122
Magnification is considered __________ distortion.
Size
123
For the same field of view (FOV), spatial resolution will be improved using
A larger matrix
124
The line focus principle expresses the relationship between
the actual and the effective focal spot.
