Rad Tech #2:test 2 Flashcards
(143 cards)
1
Q
Same quality factors of recorded detail, distortion, receptor exposure (density) and contrast
A
Image analysis
2
Q
1) Can be dangerous in radiology
2) Can aluminate preconceived ideas about image to overcome mis-perceptions
A
Image perception
3
Q
Controlling image space :
What are some radiographers challenges with taking images?
A
1) positioning area of interest so image quality will be improved
2) start with mentally visualizing abject of interest floating within body
4
Q
What makes image a good contrast, good sharpness and visibility?
A
1) The image must possess sharpness invisibility and have proper balance of factors for radiographic quality
2) Text can utilize a number of factors, formulas, and techniques that can be manipulated to get good image
5
Q
Measurable geometric ( can be measured) property of radiographic quality its an objective in nature?
A
Sharpness
6
Q
What are two factors of sharpness?
A
1) spatial resolution (new digital word)
2) distortion ( any time tube is angled)
7
Q
Photographic property that is subjective in nature ( what you see)
A
Visibility
8
Q
What are 2 factors of visibility?
A
1) receptor exposure (density)
2) contrast
9
Q
What is the formation of structural lines of image sharpness of details an image is measured?
A
Spatial resolution
10
Q
What are other names of special resolution can be called?
A
Definition (rare) Sharpness Recorded detail Detail Resolution
11
Q
What is a misrepresentation of the size/type of image recorded?
Ex) take image, make it bigger/ smaller=distortion
A
Distortion
12
Q
Which major radiographic properties records detail and distortion are inversely proportional?
(As property increases, the detail decreases)
A
Distortion
13
Q
What is the amount of blackness on an image or dark And can tell how much radiation is on an image?
A
Receptor exposure ( density~only in film)
14
Q
When an image is black what happened to the radiation?
A
The radiation hit the receptor with a lot of force
15
Q
What happen with radiation when your image is white?
A
No radiation went through
16
Q
What is the difference in density in an image?
A
Contrast
17
Q
Which radiographic property has images that have different shades of black, gray or white?
A
Contrast
18
Q
What was the name of Chad to determine whether it has good contrast?
A
1) Must have two shades
2) Must have the ability to distinguish adjacent structures from each other
19
Q
What deals with images or number of structural lines recorded
A
Resolution
20
Q
How many ways can you assess spatial resolution?
A
4
21
Q
What is the unit of resolution?
A
1p/mm ( line pairs/millimeters)
22
Q
What is dependent on metric size, pixel size, grayscale bit depth
(as metric size increases, pixel size decrease, spatial resolution increases = better image !!)
A
Spatial resolution
23
Q
Which floor of assessing spatial resolution uses the trabecular pattern? (Lines you can see in pattern)
A
Clinical evaluation
24
Q
What is a line in space, each approximately 0.1mm in size, anything greater that 0.2mm per line is intolerable?
A
Line pair
25
What are the factors that affect the degree of sharpness on an image?
1) motion=no sharpness = you lose resolution
| 2) geometry= SID,OID, focal spot (you set these/ have control over them)
26
What are the five imaging processes?
```
Image acquisition
Image processing
image archiving
Image display
Image analysis
```
27
What is the definition of distortion?
Misrepresentation of size and shape
28
What is another name for shape distortion?
True distortion
29
What is resolution measured in?
Lp/mm
| Linear pair per millimeter
30
Name 3 methods of controlling motion
1) communication
2) immobilization
3) reducing exposure time
31
What is the minimal change in MaS needed to see a noticeable change in density?
30%
32
Which has more fissure mass, muscle, or bone?
Bone
33
Short wavelengths are produced by what kind of kv?
High kv
(More energy=more penetration)
(Better for patients because x-rays go through instead of absorbing in them)
34
High contract is produced by what kind of wavelength?
Long wavelength (low kvp)
35
If u increase kvp, what happens to receptor exposure?
Receptor exposure increases
| Increase kvp by 15% = receptor exposure doubles
36
If you increase SID, what happenes to resolution?
Resolution increases
37
2 types of motion
1) voluntary (patient has control over)
| 2) involuntary (no control over; ex heart beat
38
Name 3 factors that affect distortion
Factors for size:
1) SID
2) OID
Factors for shape:
1) Angle of tube
2) Angle of patient
3) Central ray alignment
39
As Ma increases, what happens to receptor exposure?
Receptor exposure increases
40
What kind of proportion is Ma and time to each other to maintain darkness?
Inverse proportion
41
As focal spot increases, what happens to magnification?
Nothing
42
What property does focal spot only effect?
Resolution
43
As pixel size increases, what happens to resolution?
Resolution decreases
44
What kind of contract does contrast media produce?
High (short scale)
45
What percent increase is needed in KVP to double the receptor exposure?
15%
46
What is the purpose of contrast?
Make detail better
47
At what distance would the anode heel effect be noticeable?
40in
48
High contrast is produced by what type of KV?
Love KV
49
Name 2 factors that affect scale of contrast
1) KVP
2) fog
3) patient
50
To increase contrast on a radiographic image, what must be done to KVP?
Increase
| Decrease in contrast makes image lower
51
What must the radiographic image posses to have good quality?
1) resolution/ sharpness (good detail)
2) contrast
3) receptor exposure
52
The visibility properties include what?
1) contrast
| 2) receptor exposure
53
If a radiographic image has too many shades of greys (KVP is too high), what can be done to increase the contrast?
Lower the KVP
54
What is another name for quantum mottle?
Noise/ motion
55
What type of OID gives you the best detail?
Short OID/ little OID
56
If SID is decreased. What happens to receptor exposure?
Receptor exposure increases
| Tube closer to IR, image is darker/more intense
57
In the anode heel effect, at which end of the tube is the thicker body section placed?
Cathode
58
What is the purpose of filtration?
Absorbs long/low wavelengths
| Protects the patient
59
As grid ratio increases, what happens to receptor exposure?
Decreases
60
Name 3 opacity factors in patient condition
1) compactness of cells
2) cellular composition
3) surrounding structures
4) status of hollow organs
61
What type of patient (hyposthenic or hyoersthenic) will produce a radiographic image with the least amount of contrast?
Hypersthenic= more body tissue
62
What does the image look like when you have least amount of contrast?
Lots of greys on an image
63
Which of the factors listed below will produce the shortest scale of contrast?
A) 300 Ma 1/30 sec 50KV
B) 100Ma 1/10 sec 60KV
C) 50Ma 1/5 sec 70KV
D) 200Ma 1/20sec 80KV
A (we want the lowest KV factor)
64
Which of the above factors will produce an image with the greatest amount of receptor exposure?
A) 300Ma 1/30sec 50KV
B) 100Ma 1/10sec 60KV
C) 50Ma 1/5sec 70KV
D) 200Ma 1/20sec 80KV
D
| We want high MAS and high KVP
65
What type of focal spot produces the best detail?
Small focal spot
66
What is the best method for controlling involuntary motion?
Recuse exposure time
67
The difference in the intensity of x-ray transmitted by a particular body part because of its differing absorption characteristics is known as...
Subject contrast
68
The ability in an image to demonstrate differences in density is measured by the ratio of one density as compared to another is known as...
Scale of contrast
69
The visible difference between adjacent densities demonstrated on the radiographic image that results from the patient is known as...
Subject contrast
70
A radiographic image that indicates short, abrupt change from the minimum to maximum density on an image is it to possess what contrast?
High (short scale)
71
The blackness on the film is called?
Density or receptor exposure
72
2 major controlling factors of density are ....
Time and Ma
| ma=current flow
73
How can grids affect film density?
Grid ratio increases, receptor exposure (density) decreases
74
How does kilovoltage (Kv) affect film density?
KVP increases, density increases
75
An increase of kilovoltage (Kv) by what percent, can double the exposure to the film?
15%
76
What is defined as the different in densities between 2 or more densities on a radiograph Ir the difference in density of 2 adjacent structures?
Contrast
77
What is the penetrating ability of x-ray photons controlled by?
Kilovoltage
78
Short wavelengths provide what type of penetration? (High or low)
High
79
Long wavelengths produce what kind of penetration? (High or low)
Low
80
Short scale contrast is obtained by using a (higher) (lower) kilovoltage?
Lower
81
A radiographic that has few shades of grey with mostly blacks and white is referred to as what scale of contrast and what degree of contrast in adjacent structures?
Short scale of contrast
| High degree of contrast
82
Using a (high) (low) range of kilovoltage more areas are not penetrated resulting in white or clear areas on the radiograph
Low range
83
If areas of the object have not been penetrated and no radiation gets to the film, contrast is not present
True or false
True
84
High degree of contrast and high contrast means short scale of contrast
True or false
True
85
Kilovoltage controls contrast
Yes or no
Yes
86
Kilovoltage controls penetration
Yes or no
Yes
87
Kilovoltage controls radiographic contrast
Yes or no
Yes
88
The function of contrast is to make detail visible
Yes or no
Yes
89
To change the scale of contrast, kilovoltage must be decreases
Yes or no
Yes
90
Low KVP produces what contrast?
High contrast produced
91
To increase the scale of contrast, kilovoltage must be increased
Yes or no
Yes
92
Is short scale contrast
A) higher kilovoltage
B) lower kilovoltage
B lower
93
Long scale contrast
A) higher kilovoltage
B) lower kilovoltage
A higher
94
Low contrast
A) higher kilovoltage
B) lower kilovoltage
A higher
95
Low degree contrast
A) higher kilovoltage
B) lower kilovoltage
A higher
96
High degree of contrast
A) higher kilovoltage
B) lower kilovoltage
B lower
97
High contrast
A) higher kilovoltage
B) lower kilovoltage
B lower
98
“Too much contrast”
A) higher kilovoltage
B) lower kilovoltage
B lower
99
To increase contrast on a radiograph you should (increase) (decrease) the kilovoltage?
Decrease
100
To lengthen the scale of contrast, the kilovoltage must be (increases) (decreases)
Increase
101
A film with many shades of great is said to have (long) (short) scale of contrast?
Long
102
A film with mostly black and white areas and few shades of geeaybis said to have a (long) (short) scale of contrast?
Short
103
The factor that controls contrast is?
KV
104
You can have underexposure and overexposure on the same radiograph with a very short scale of contrast
True or false
True
105
The part must be penetrated to have contrast
True or false
True
106
Another term employed to describe size distortion is?
Magnification
107
What are 2 influences contributing to size distortion?
SID
| OID
108
Shape distortion can be used to an advantage at times. List 2 purposes of shape distortion when used in this manner.
1) to avoid superimposition
| 2) demonstrate anatomy
109
Magnification increases with increasing what?
OID (object source distance)
110
A foreshortened image can result from what?
From an inclined object
111
Which of the following does NOT contribute to image distortion?
a. Kvp
b. Object size
c. Object shape
d. Object position
A. Kvp
112
An average visual acuity is represented by the ability to distinguish how many line pairs per millimeter? (LP/mm)
10
113
The most determined factor contributing to image in harp was is?
Motion
114
How does quantum mottle affect the quality of the radiographic image?
Not enough photons will reach the IR to create an image, or the image will turn out spotty
115
What is it meant by image resolution? How is it identified and measured?
How clear an image is after the exposure was taken
Measures # of structural lines
116
The greatest amount of geometric on sharpness is usually attributed to which factor?
OID
117
When u decrease image distance, resolution increases or decreases?
Decreases
118
When SID increases, recorded detail increases or decreases?
Increases
119
As unsharpness decreases, sharpness increases or decreases?
Increases
120
As focal spot size decreases, spatial resolution increases or decreases?
Increases
121
As OID decreases, recorded detail increases or decreases?
Increases
122
As motion increases, unharness increases or decreases?
Increases
123
As MAS decreases, sharpness increases or decreases?
Stays the same it doesn’t effect resolution
124
As OID increases, resolution increases or decreases?
Decreases
125
The exposure factor related to the quantity of an x-ray exposure is:
Milliamperage
126
At a 40in SID, you would probably see the anode heel effect of you were using what size image receptor?
14 X 17
127
If a body part is 17in long and thickness and opacity are uniform throughout, what effects, if any, would this have on the image?
The image will appear darker at the cathode end
128
Describe the purpose of compensating filters in radiography
Evens out the densities throughout an image
129
What does MA measure?
Measurement of quantity of current traveling through tube from cathode (-) to anode (+)
130
What is the main factor of density?
mAs
131
When you have an orthopedic cast, do u need more or less mAs ?
More
132
Long wavelengths have what kind of frequency, what type of energy, and what kind of KV?
Have low frequency
Low energy
Low kv
133
Short wavelengths have what frequency, what energy, and what kv?
High frequency
High energy
High kv
134
When you have a high contrast image, what color(s) will the image portray?
Black and white
135
Low contrast has what color(s) portrayed on the image?
Scales of greys
136
As KVP decreases, what happens to contrast?
Increase contrast
137
What is the minimum filtration for 50-70 KVP?
1.5mm
138
What is the minimum filtration for under 50 KVP?
.5mm
139
What is the minimum filtration for over 70 KVP?
2.5mm
140
What type of filter does not safe Patient dose of exposure?
Compensating filters
141
What does compensating filters look like on an image or what does a demonstrate?
Greys in image
142
What is the formula for dry casts
You double the mAs
143
What is the formula for wet casts?
Double the mAs and add 10%
