Exam 2 Flashcards
1
Q
What are the 3 characteristics of radiation?
A
o X-ray beam quality
o X-ray quantity
o X-ray bream intensity
2
Q
What exposure factors are controlled on older panels?
A
- kVp control settings
- mA control settings
- Time setting
3
Q
What determines the energy penetrating power of radiation?
A
Wavelength
4
Q
What wavelength equals more penetrating power?
A
Short
5
Q
What wavelength equals less penetrating power?
A
Longer
6
Q
mean energy of the x-ray beam (wavelength + energy)
A
Quality
7
Q
What is the quality of x-rays controlled by?
A
Kilovoltage
8
Q
What type of quality beam is the outcome of increased kV and faster electrons?
A
High quality beam
9
Q
How much kV does current dental radiography use?
A
65-100 kV
10
Q
Increase kV + density increases = what image?
A
Darker image
11
Q
Decrease kV+ density increases = what image?
A
Lighter image
12
Q
Higher kV = what contrast?
A
Low contrast
13
Q
Lower kV = what contrast?
A
High contrast
14
Q
Low contrast =
A
shades of gray
15
Q
High contrast =
A
black and white
16
Q
Greater than or equal to 90 = what kVp?
A
High kVp
17
Q
65-70 = what kVp?
A
Low kVp
18
Q
What is the only thing that adjusts contrast?
A
kVp
19
Q
What scale of contrast = 2 densities?
A
Short scale
20
Q
What scale of contrast = lots of density?
A
Long scale
21
Q
Device used to demonstrate short-scale contrast and long-scale contrast
A
Stepwedge
22
Q
What is stepwedge used for?
A
Quality control
Machine calibration
23
Q
What contrast is good for detecting periodontal disease and periapical lesions?
A
Low contrast
24
Q
What contrast is good for detection of caries?
A
High contrast
25
time x-rays are being produced
Exposure time
26
Longer exposure time = more x-rays = what image?
Darker image
27
Shorter exposure time = less x-rays = what image?
Lighter image
28
What are older machines measured in?
Impulses
29
What are new machines measured in?
Hundredths/seconds
30
What is x-ray beam quantity controlled by?
Milliamperage
31
What dictates number of electrons passing through cathode filament?
Amperage
32
What mA = increase in number of electrons from cathode to anode?
Increased mA
33
kVp =
quality
34
mA =
Quantity
35
What regulates temperature of cathode filament?
Milliamperage
36
What mA = increased temperature (more electrons)?
Higher mA
37
What mA = decreased temperature?
Lower mA
38
Increased number of electrons =
More x-rays
39
Increase mA + increased density = what image?
Darker image
40
Decreased mA + decreased density =
Lighter image
41
What is adjustable?
Exposure time
42
What do we base exposure time off of?
Patient size
43
product of quantity and quality per unit of area per unit of time to exposure
Intensity
44
What is intensity affected by?
kV
mA
exposure time
distance
45
What regulates penetrating power by controlling speed of electrons?
kV
46
What kV = more energy and shorter wavelength?
Higher kV
47
What kV = increased intensity?
Increased kV
48
What regulates penetrating power by controlling number of electrons and x-rays produced?
mA
49
What mA = more energy?
Higher mA
50
What mA = increased intensity?
Increased mA
51
target to patient’s skin
Target-surface distance
52
Explains how distance affects the intensity of the x-ray beam
inverse square law
53
If distance is doubled, beam is ___ less intense
1/4
54
If distance is tripled, beam is ___ less intense
1/9
55
Amount of material we need to reduce x-ray beam intensity by half
Half-value layer (HVL)
56
What material do we need for HVL?
Aluminum filters
57
What does HVL measurement depend on?
The penetrating quality beam
58
What HVL = more penetrating beam?
Higher HVL
59
What are the geometric characteristics?
o Sharpness
o Magnification
o Distortion
60
Capability of the receptor to be able to reproduce the distinct outlines of an image
Sharpness
61
lack of sharpness, blurring of an edge
Penumbra
62
What is sharpness influenced by?
Focal spot size
Film composition
Movement
63
o Tungsten target of anode
o Determined by the manufacturer of x-ray equipment
Focal spot size
64
What focal spot = sharper image?
Smaller focal spot
65
What film = larger crystals = less sharpness?
Faster film
66
What film = smaller crystals = more sharpness?
Slower film
67
What crystals produce sharper lines?
Smaller crystals
68
What results in loss of sharpness?
Tube head movement
Receptor movement
Patient movement
69
What = non-diagnostic image?
Movement
70
Image that appears larger than actual size
Magnification
71
What is magnification influenced by?
Object-receptor distance
Target-receptor distance
72
What results from distortion?
Foreshortening
Elongation
73
What influences distortion?
Objected-receptor alignment
74
Why would we use bisecting technique over paralleling?
shallow pallet
hard time biting
rubber dam
75
formed by two lines diverging from a point
angle
76
imaginary line that splits angle into two equal halves
bisector
77
shape that is formed when three points are connected by three straight lines, makes three different angles
triangle
78
triangle with all even sides, angles all the same
Equilateral triangle
79
equal triangles
Congruent triangles
80
side of triangle that sits opposite of 90-degree right angle
Hypotenuse
81
Two triangles are equal if the triangles have two equal angles and share a common side
Rule of isometry
82
What is the central ray perpendicular to in bisecting technique?
Imaginary bisector
83
what is a result of Vertical angulation being too high?
Foreshortening
84
What is a result of Vertical angulation being too low?
Elongation
85
What are the bisecting technique devices?
Rinn BAI System
Stabe
Snap-A-Ray
86
What is the result of incorrect horizontal angulation?
overlap
87
What results in positive vertical angulation?
Angling PID down
88
What results in negative vertical angulation?
Angling PID up
89
What type of angling degree do we use when exposing bitewings?
Positive 10-degrees
90
What artifacts need removed for x-rays?
Jewelry
Glasses
Dentures
91
How do we prep our equipment?
o Set out holding device
o Control settings
92
What is the receptor position for bisecting technique?
1/8th inch beyond incisal or occlusal, apical end against palate
93
What are the 5 bisecting technique rules?
1. receptor placement
2. receptor position
3. vertical angulation
4. horizontal angulation
5. receptor exposure
94
What needs to be parallel to the floor for the maxillary arch?
ala tragus
95
What needs to be parallel to the floor for the mandibular arch?
Occlusal plane
96
What is the point of entry clue for Maxillary centrals?
midline + ala tragus
97
What is the point of entry clue for maxillary canines?
canine fossa + ala tragus
98
What is the point of entry clue for maxillary premolars?
inner canthus of eye + ala tragus
99
What is the point of entry clue for mandibular centrals?
midline + symphysis of chin
100
What is the point of entry clue for mandibular canines?
midline + symphysis of chin
101
What is the point of entry clue for mandibular premolars?
inner canthus of eye + symphysis of chin
102
What is the point of entry clue for mandibular molars?
outer canthus of eye + symphysis of chin
103
What is the point of entry clue for bitewings?
premolars/molars + occlusal plane
104
What are advantages of bisecting technique?
o No beam alignment device
o Decreased exposure time
105
What are disadvantages of bisecting technique?
o Dimensional distortion
o Angulation problems
106
What error occurs?
- Appear blank/white, no anatomy
- Appears clear
Unexposed receptor
107
What error occurs?
- Film appears black
Film exposed to white light
108
What error occurs?
- Appears dark or high in density
Overexposed
109
What error occurs?
- Appears light or low in density
Underexposed
110
What error occurs?
- No apices seen on receptor
- Excessive radiolucent area
Root apex missing
111
What error occurs?
- Occlusal plane tipped/tilted
Dropped corner/downhill composition
112
What error occurs?
- Contact of one area superimposed over contact of adjacent tooth
Overlap
113
What error occurs?
- Partial image loss
- Clear or white unexposed area
Cone cut
114
What error occurs?
- Blunted roots
Foreshortening
115
What error occurs?
- Long, stretched out structures
Elongation
116
What error occurs?
- Not enough max. or mand. Anatomy
- No crestal bone visible in image
Vertical placement
117
What error occurs?
- Appropriate anatomy not seen or centered in image
Horizontal placement
118
What error occurs?
- Bent = distorted image (stretched)
Bending/creasing of film
119
What error occurs?
- Radiolucent or radiopaque artifacts, scratches
Debris
120
What error occurs?
- Finger present in image
Phalangioma
121
What error occurs?
- Film or indirect digital imaging
Double exposure
122
What error occurs?
- Blurry image
Movement
123
What error occurs?
- Film: herringbone pattern
- Digital sensors: blank or white
Receptor backwards/reversed
124
What error occurs?
- Radiopaque outline of cord
Wire/cord
