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Oral Radiology > Exam II study guide > Flashcards

Exam II study guide Flashcards

1
Q

Shadow; the image of the object we receive:

A

umbra

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2
Q

Edge gradient; the unsharp area; area around the margins of the object

A

penumbra

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3
Q

What do we try to minimize in. a radiographic image?

A

penumbra

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4
Q

How do we minimize penumbra?

A

by having an increased source to object ratio

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5
Q

Because there are multiple x-ray photons that come and interact with the edges of the object, it creates a blurry margin referred to as:

A

penumbra

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6
Q

3 factors that affect the quality of the radiograph:

A
  1. image sharpnress
  2. image magnification
  3. image shape distortion
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7
Q

Equal enlargement:

A

magnification

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8
Q

unequal enlargement:

A

shape distortion

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9
Q

enlargement of the radiographic image, compared to the actual size of the object:

A

magnification

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10
Q

Image shows true shape of object:

A

magnification

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11
Q

What does magnification have to do with?

A

the DIVERGENCE due to the distance of the receptor, object, and beam

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12
Q

Variation from the true shape of an object and unequal magnification of certain parts of the object:

A

shape distortion

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13
Q

What does shape distortion have to do with?

A

improper alignment/ANGULATION of receptor, object, and beam

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14
Q

3 ways to maximize image sharpness:

A
  1. radiation source
  2. source-to-object distance
  3. object-to-receptor distance
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15
Q

Discuss the radiation source if we are trying to maximize image sharpness:

A

radiation source should be as small as possible (smaller focal spot = greater sharpness because there are fewer photons interacting with the object)

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16
Q

Smaller focal spot = ____ sharpness

A

greater

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17
Q

Smaller radiation source = ____ focal spot = ____ sharpness

A

smaller; greater

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18
Q

Although a smaller radiation source is a mechanisms to maximize image sharpness, this is not something:

A

we can control after machinery is bought

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19
Q

Discuss the source-to-object distance if we are trying to maximize object distance:

A

source-to-object distance should be as long as possible

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20
Q

How can source-to-object distance be controlled when trying to maximize image sharpness?

A

Can be controlled by length of cone (larger cone = increased sharpness due to decreased divergence)

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21
Q

Larger cone = ____ sharpness due to ____

A

increased sharpness; decreased divergence

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22
Q

Discuss the objet-to-receptor distance if we are trying to maximize image sharpness:

A

Object-to-receptor distance should be as short as possible (get tooth as close to image receptor as possible)

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23
Q

If we are trying to increase image sharpness by adjusting the object-to-receptor distance, how do we control this?

A

can be controlled by where operator places image receptor

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24
Q

When trying to maximize sharpness, discuss what you should do to the following:

  1. radiation source
  2. source-to-object distance
  3. object-to-receptor distance
A
  1. radiation source should be as small as possible (can’t be adjusted after buying though)
  2. source-to-object distance should be as long as possible (controlled by length of cone- larger cone = sharper image)
  3. object-to-receptor distance should be as short as possible (controlled by operator placement of image receptor)
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25
Q

2 ways to minimize magnification:

A
  1. source-to-object distance should be as long as possible
  2. object-to-receptor distance should be as short as possible
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26
Q

Explain why the object-to-receptor distance should be as short as possible when trying to minimize magnification:

A

shorter object to image receptor distance results in less magnification and greater sharpness due to LESS DIVERGENCE

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27
Q

Explain what would result from:

longer object to image receptor distance:

A

greater magnification; less sharpness; due to more divergence

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28
Q

What are 2 ways to minimize distortion?

A
  1. object and receptor should be PARALLEL
  2. beam should be PERPENIDICULAR to both object and receptor
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29
Q

What is the effect of the following on a radiographic image?

  • smaller radiation source
  • longer source-to-object distance
  • shorter object-to-receptor distance
A

maximized image sharpness

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30
Q

What is the effect of the following on a radiographic image?

  • longer source-to-object distance
  • shorter object-to-receptor distance
A

minimized image magnification

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31
Q

What is the effect of the following on a radiographic image?

  • object and receptor are PARALLEL
  • beam is PERPINDICULAR to both object and receptor
A

minimized shape distortion

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32
Q

List the 5 rules for accurate image formation:

A
  1. focal spot as small as possible
  2. source-object distance as long as possible
  3. object-receptor distance as short as possible
  4. object (tooth) parallel to receptor
  5. beam perpendicular to object (tooth) and receptor
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33
Q

The 5 rules for accurate image formation include:

  1. focal spot ____
  2. source-object distance ___
  3. object-receptor distance ___
  4. object (tooth) ____ to receptor
  5. beam ____ to object (tooth) & receptor
A
  1. as small as possible
  2. as long as possible
  3. as short as possible
  4. parallel
  5. perpendicular
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34
Q

What are the two techniques used for PA radiography?

A
  1. paralleling technique
  2. bisecting angle technique
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35
Q

What type of cone should be used according to the paralleling technique used for PA radiography?

A

long cone

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36
Q

What is the “preferred” technique for PA radiography?

A

paralleling technique

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37
Q

Describe the components to the paralleling technique for PA radiography:

A
  1. use long cone
  2. receptor parallel to tooth
  3. beam perpendicular to tooth and receptor
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38
Q

What problem can we run into when using the paralleling technique for PA radiography?

A

Can run into problem in MAXILLARY radiographs due to curvature of the palate

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39
Q

What does the paralleling technique for PA radiography violate?

A

violates rule of increased object-receptor distance so an increased source-receptor distance is utilized (long cone)

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40
Q

Because the paralleling technique for PA radiography violates the rule of increased object-receptor distance, what is done to make up for this? How?

A

increase source-receptor distance; using a long cone

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41
Q

What technique for PA radiography can be used if the paralleling technique cannot be used?

A

bisecting angle technique

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42
Q

What type of cone is preferred for the bisecting angle technique for PA radiography?

A

long cone preferred but short cone can be used

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43
Q

What rule is the bisecting angle technique for PA radiography based on? Explain this rule

A

Based on rule of isometry: if two triangles have equal angles and a common side, then the two triangles are equal

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44
Q

In the bisecting angle technique for PA radiography, what angle is bisected?

A

the angle formed by the plane of the tooth and the plane of the receptor

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45
Q

When is the beam directed in the bisecting angle technique for PA radiography?

A

beam is directed perpendicular to the bisecting line

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46
Q

In the bisecting angle technique for PA radiography, the angle formed by ____ and ___ is bisected and the beam is directed ____ to the ____

A

the plane of the tooth and the plane of the receptor; perpendicular to the bisecting line

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47
Q

In the bisecting angle technique for PA radiography, what is NOT bisected?

A

neither the tooth or receptor is bisected

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48
Q

Tube shift method/ buccal object rule can be explained by the:

A

SLOB rule

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49
Q

SLOB stands for

A

Same lingual; Opposite buccal

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50
Q

When you move the tube head mesially, and the object moves mesially, where is the object located?

A

lingually

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51
Q

What causes foreshortening (an error):

A

tooth not parallel to receptor and beam directed perpendicular to RECEPTOR

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52
Q

Radiographic image of the object (tooth) appears shorter than it actually is:

A

forshortening

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53
Q

How would the radiographic image appear if foreshortening occurs?

A

image appears shorter than it actually is

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54
Q

Foreshortening is a result of improper:

A

VERTICAL angulation

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55
Q

What causes elongation (an error)?

A

tooth not parallel to receptor and beam is directed perpendicular to TOOTH

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56
Q

Radiographic image of the object (tooth) appears longer than it actually is. Root apices may be cut off:

A

elongation

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57
Q

Elongation is a result of improper:

A

VERTICAL angulation

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58
Q

What error causes overlapping of contacts?

A

improper HORIZONTAL angulation

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59
Q

Reduction of the intensity of an x-ray beam as it traverses matter:

A

attenuation

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60
Q

absorption =

scatter=

A

photoelectric effect

coherent & compton scattering

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61
Q

Interactions of x-radiation with matter (attenuation types): (4)

A
  1. No interaction (9%)
  2. Photoelectric effect (27-30%)
  3. Compton scatter (57-62%)
  4. Coherent (Thomson) scatter (7%)
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62
Q

What type of interactions with x-radiation (attenuation types) are shown?

A

A: no interaction (9%)
B: coherent scattering (7%)
C: photoelectric absorption (27-30%)
D: compton scattering (57-62%)

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63
Q

When the x-ray photon enters an object (patient) and exits with no change in its energy:

A

no interaction (9%)

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64
Q

When the x-ray photons collide with an orbital electron an d lose energy; the ejected photoelectron loses its energy:

A

photoelectric absorption (27-30%)

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65
Q

In the photoelectric absorption process (27-30%), ____ occurs which results in ___.

A

ionization; biologic effect

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66
Q

When the x-ray photon collides with an outer orbital electron losing some energy. The x-ray photon continues in a different direction with less energy creating more scatter until all energy is lost:

A

Compton scattering (57-62%)

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67
Q

In the Compton scattering process (57-62%), ____ occurs which results in ___.

A

ionization; biologic effect

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68
Q

Rules that govern the probability of photoelectric absorption and compton scatter:

A

the ionized matter is unstable and seeks a more stable configuration; which may affect biologic structure, or both

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69
Q

X-ray photons of low energy interacts with an outer orbital electron and changes direction:

A

Coherent scattering

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70
Q

In coherent scattering process (7%), no photoelectron is produced and therefore:

A

no ionization occurs

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71
Q

How do differential absorption/photoelectric absorption help in image formation?

Produces ___ that generates the detail of the image. Some x0rays are absorbed in the tissue and some pass through the anatomical tissue.

A

contrast

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72
Q

The process of image formation is a result of:

A

differential absorption

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73
Q

Varying x-ray intensities exiting the anomic area of interest form the:

A

latent image

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74
Q

measure of the biological effectiveness of radiation to ionize matter:

A

QF

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75
Q

Have a threshold and severity is proportional to the dose:

A

deterministic effects

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76
Q

Describe the curve of deterministic effects of radiation:

A

is a threshold, non-linear dose curve

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77
Q

Has NO dose threshold. Probability of occurrence is proportion to dose BUT severity of effects does NOT depend on dose:

A

stochastic effects of radiation

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78
Q

Stochastic effects of radiation on somatic cells results in:

A

genetic mutations that cause malignancy

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79
Q

Stochastic effects of radiation on germ cells results in:

A

heritable effects

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80
Q

Describe the curve of stochastic effects:

A

non-threshold linear

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81
Q

What cancers have the highest risk from dental radiographic exposure?

A

Leukemia and thyroid cancer

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82
Q

Direct radiation effects on cellular structures its caused by:

A

rupture in the cell wall of a biologically active molecule

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83
Q

What factors affects radio sensitivity to the greatest degree?

A

Age

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84
Q

Children aged ____ are ____x more likely of radiation induced cancer

A

children aged 2-10; 2-6x more likely

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85
Q

Radiation induced tissues changes that are believed to follow these dose-response curves:

Threshold non-linear –>

Linear non-threshold –>

A

deterministic effects

stochastic effects

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86
Q

Acute radiation syndrome includes: (4)

A
  1. prodromal period
  2. hematopoietic syndrome
  3. GI syndrome
  4. CNS/CV syndrome
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87
Q

Prodromal period:

____ R

____Gy

Describe the lethality:

A

Less than 200 R

Less than 2 Gy

non-lethal

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88
Q

Shortly after exposure to whole body radiation individual may develop nausea, vomiting, diarrhea, and anorexia:

A

Prodromal period

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89
Q

Describe prodromal period of acute radiation syndrome:

A
  • shortly after exposure to whole body radiation individuals may develop nausea, vomiting, diarrhea, and anorexia
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90
Q

Discussion the timeline of symptom resolution with prodromal period of acute radiation syndrome:

A

symptoms resolve after several weeks

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91
Q

Hematopoietic syndrome:

____ R

____Gy

Describe the lethality:

A

200-1000 R

2-10 Gy

Lethal

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92
Q

Irreversible injury to the proliferative capacity of of the spleen and bone marrow with loss of circulating peripheral blood cells:

A

Hematopoietic syndrome

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93
Q

In hematopoietic syndrome, the person may develop infection from ____ and ____. The person may hemorrhage from ____. The person may develop anemia from _____.

The most lethal part of hematopoietic syndrome is:

A

lymphopenia & granulocytopenia;

thrombocytopenia;

erythrocytopenia;

sepsis

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94
Q

Describe the timeline with hematopoietic syndrome of acute radiation syndrome:

A

death within 10-30 days

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95
Q

GI Syndrome:

____ R

____Gy

Describe the lethality:

A

1000-10k R

10-100 Gy

Supra lethal

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96
Q

Extensive damage to the GI system. Injury to the rapidly proliferating basal epithelial cells of intestine leading to atrophy and ulceration:

A

GI syndrome

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97
Q

In GI syndrome, the loss of ___ and ____ causes hemorrhage, ulceration, diarrhea, dehydration, weight loss, & infection:

A

plasma & electrolytes

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98
Q

Describe the timeline with GI syndrome of acute radiation syndrome:

A

Death within 3-5 days

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99
Q

CNS and CV Syndrome

____ R

____Gy

Describe the lethality:

A

Greater than 10k R

Greater than 100 Gy

Supralethal

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100
Q

Radiation induced damage to neurons and fine vasculature of the brain. Results in intermittent stupor, incoordination, disorientation, and convulsions:

A

CNS and CV syndrome

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101
Q

Describe the timeline with CNS and CV syndrome of acute radiation syndrome:

A

Irreversible damage with death in a few minute to 48 hours

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102
Q

Relative dose ranges to oral tissues from oral cancer radiation treatments:

Total radiation doses to treat malignant tumors ranges from:

A

6000-8000 Rads or 60-80 Gy

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103
Q

Relative dose ranges to oral tissues from oral cancer radiation treatments:

Solid tumors=

Lymphomas=

Inraoral cancer=

A

solid tumors = 60-80 Gy

lymphomas= 20-40 Gy

intraoral cancer= 50 Gy

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104
Q

Common dental radiation:

1 Gy=

A

1 million mSv

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105
Q

Common dental radiation:

Single intraoral radiograph=
FMX=
Pano=

A

Single= 1.3 mSv
FMX= 33 mSv
Pano= 9 mSv

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106
Q

Potential long term effects of dental ionizing radiation to the head and neck area:

Oral tissue are subjected to high doses of radiation during treatment of malignant tumors or the: (5)

A
  1. soft palate
  2. tonsils
  3. floor of mouth
  4. nasopharynx
  5. hypopharynx
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107
Q

Potential long term effects of dental ionizing radiation to the head and neck area:

Oral tissue are subjected to high doses of radiation during treatment of malignant tumors or the soft palate, tonsils, floor of mouth, nasopharynx and hypo pharynx.

This can have effects on the:

A

oral mucosa, taste buds, salivary glands, teeth, bone, and muscle

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108
Q

Discuss the potential longer term effects on dental ionizing radiation to the following area: Oral mucosa

A

mucositis (secondary infections)

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109
Q

Discuss the potential longer term effects on dental ionizing radiation to the following area: Taste buds

A

lost of taste (hypoguesia)

110
Q

What results in loss of taste by the 2nd-3rd week of treatment.

A
  1. epithelial atrophy
  2. xerostomia
  3. mucositis
111
Q

Epithelial atrophy, xerostomia & mucositis result in loss of taste by the 2nd-3rd week of treatment. When will recovery of taste return?

A

2-4 months following treatment

112
Q

Discuss the potential longer term effects on dental ionizing radiation to the following area: Salivary glands:

A

xerostomia

113
Q

Describe the loss of salivary secretions causing xerostomia in radiation treatment:

A

marked and progressive loss

114
Q

If some of the salivary gland has been spared following radiation treatment, the dryness subsides in:

A

6 mo-1 year

115
Q

____ saliva makes the mouth dry and tender, causing difficulty swallowing following radiation

A

scanty

116
Q

Residual saliva has a lowered pH from 6.5-5.5 following radiation which can initiate:

A

decalcification of enamel

117
Q

Describe the effects of radiation on the buffering capacity of the saliva:

A

the buffering capacity of saliva is reduced to 40-45%

118
Q

Pertaining to salivary glands, ____ cells (especially in the ___) are very sensitive to x-rays and replaced by fibrosis and adiposis

A

parenchymal cells; parotid gland

119
Q

Parenchymal cells (especially of the parotid glands) are very sensitive to x-rays and are replaced by:

A

fibrosis & adiposis

120
Q

Rampant form of decay that may effect individuals who received a course of radiation therapy that include exposure of salivary glands:

A

radiation caries

121
Q

Radiation carries is a ___ effect of radiation

A

INDIRECT

122
Q

Discuss the potential longer term effects of dental ionizing radiation to the following area: Teeth

A

lack of or retarded development

123
Q

Adult teeth are very resistant to the ___ effects of radiation exposure

A

DIRECT

124
Q

True/False- There is a discernible effect on the structure of adult teeth and radiation does increase the solubility of teeth.

A

False- there is NO discernible effect on the structure of adult teeth and radiation DOES NOT increase the solubility of teeth

125
Q

Describe the potential effects of dental ionizing radiation on erupted teeth:

A

Only indirect effects to erupted teeth

126
Q

When primary teeth are irradiated during the development stage, what may occur?

A

their growth may be severely retarded

127
Q

Concerning primary teeth, if radiation PRECEDES calcification:

A

The tooth bud may be destroyed

128
Q

Concerning primary teeth, if the radiation is AFTER initiation of calcification the teeth may demonstrate:

A

malformations and arresting general growth

129
Q

Irradiated primary teeth with altered root formation will still erupt because:

A

eruptive mechanisms is much more radiation resistant

130
Q

A dose as low as ___ at the age of 5 months has been reported to cause ___ of enamel

A

200R; hypoplasia

131
Q

Discuss the potential longer term effects of dental ionizing radiation to the following area: Bone

A

Osteoradionecrosis

132
Q

Primary damage to bone is from irradiation is to:

A

fine vasculature and bone marrow (affecting vascular and hemopoietic elements)

133
Q

Discuss the potential longer term effects of dental ionizing radiation to the following area: muscle

A

fibrosis and inflammation

134
Q

The fibrosis and inflammation that occur in the muscle from dental ionizing radiation results in:

A

contracture and truisms in the muscles

135
Q

Sources of natural and man-made background ionizing radiation exposure to the population:

medical = __mSv

natural = __ mSv

other (man-made) = ___ mSV

A

medical = 3.2 mSv

natural= 3.0 mSv

other = 0.1 mSV

136
Q
  • consumer produces (TV, Apple Watch, computers)
  • medical imaging
  • airport scanners
  • nuclear fuel cycle
  • weapons production
  • fall-out from atomic weapons

These are all examples of:

A

man-made/artificial sources of background ionizing radiation exposure

137
Q
  • external (cosmic, terrestrial)
  • internal (radon= majority),
  • cosmic

These are all examples of:

A

natural sources of background ionizing radiation exposure

138
Q

The majority of manmade exposure of background ionizing radiation =

A

medical imaging (greater than 50%)

139
Q

The majority of n natural exposure of background ionizing radiation=

A

radon (~54%)

140
Q

Sources of medical imaging radiation exposure are: (4)

What do these add up to a total of?

A
  1. CT scanning
  2. Nuclear medicine
  3. Radiography
  4. Interventional

3.2 mSv

141
Q

The effective dose per individual in the U.S. population (mSv) in the 1980s was ____ and in 2006 was ___

A

3.6 mSv; 6.2 mSv

142
Q

Ways to change the EFFECTIVE DOSE of radiation is accomplished by variations in: (4)

A
  1. receptor type
  2. types of exams
  3. collimation shape
  4. collimation length
143
Q

Explain the following- Ways to change the EFFECTIVE DOSE of radiation is accomplished by variations in receptor type:

A

The faster the receptor type, the less patient exposure

(#1 ways to reduce exposure)

144
Q

What is the #1 way to reduce radiation exposure to a patient?

A

Receptor type- faster the receptor type, the less patient exposure

145
Q

Ways to change the EFFECTIVE DOSE of radiation is accomplished by variations in in type of exams such as:

A

BW, Pano, PA, CBCT, Etc.

146
Q

Ways to change the EFFECTIVE DOSE of radiation is accomplished by variations in collimation shape:

A

rectangular collimator with 2.75” diameter is preferred

147
Q

Ways to change the EFFECTIVE DOSE of radiation is accomplished by variations in collimator length:

A

The longer the collimator is, the less patient exposure and sharper the image

148
Q

The amount of radiation that will not produce any serious, harmful, or deleterious effects on the individual receiving it:

A

Maximum Permissible Dose (MPD)

149
Q

The MPD occupational limits =

A

5 REM/year (5000 mREM)

*50 mSV

150
Q

The average dental personnel exposure to radiation:

A

0.2 mSv

151
Q

The MPD non-occupational limits=

A

0.5 REM/year (500mREM)

  • 5 mSv
152
Q

The average annual effective dose (natural + man-made) is about:

A

3.6 mSv

153
Q

The MPD pregnant occupational limits =

A

0.5 REM/year (500mREM)

  • 5 mSv (at 9 months)
  • 0.5 mSv (at 1 month)
154
Q

In what population are radiographs indicated for acute, painful dental problems only (when outweighs risk vs. benefit)

A

pregnant women

155
Q

What cancers have the highest risk from dental x-radiation exposures?

A

thyroid cancer & leukemia

156
Q

What is the THRESHOLD radiation erythema dose?

A

250 Rads

157
Q

What is the AVERAGE radiation erythema dose?

A

500 Rads=

158
Q

What is the MAXIMUM radiation erythema dose?

A

700 Rads (1st degree burn)

159
Q

In 1959, how many exposure were required to cause TED?

A

62 exposures (1250/20)

160
Q

In 2023, 1/3 of TED is delivered with ~___ intraoral dental exposures at a ___ focal distance

A

298; 8”

161
Q

In 2023, using properties of inverse square law, the dose is decreased to ~37% if the focal distance is:

A

doubled (16”)

~473 exposures

162
Q

Benefits of dental radiography include: (9)

A
  1. interproximal caries diagnosis
  2. severity (depth) and extent of caries
  3. periodontal bone loss (alveolar crest)
  4. root configuration
  5. periradicular pathology
  6. basal bone pathology in jaws
  7. location of 3rd molar roots and IA
  8. anatomy assessment for implants
  9. calculus
163
Q

Compared to visual examination:

  • digital bitewings identified ____x more caries
  • conventional bitewings identified ___x more caries
A

3.2x; 2.9x

(6% occlusal decay and 94% interproximal decay)

164
Q

20% incidence in asian and chinese populations & 10-12% incidence in native North American populations:

A

Lingual root of mandibular first molars

165
Q

Basal bone pathology in jaws: hyperdontia is most common in the:

A

premolar area

166
Q

What are the goals for maxillofacial and oral radiology?

A
  1. reduce radiation exposure
  2. maintain a high degree of diagnostic efficiency
167
Q

Its a juggling act to:

A

reduce a patients radiation exposure yet maintain a high degree of diagnostic efficiency

168
Q

ALARA:

A

As Low As Reasonably Achievable

169
Q

The guiding principle of radiation protection:

A

ALARA & ALADA

170
Q

Since the rpbomablility or severity of biological damage increases as the radiation does increases, it is desirable to avoid:

A

receiving even the smallest dose of unnecessary radiation

171
Q

With ALARA, what was prioritized?

A
  1. Time
  2. Distance
  3. Shielding factors
172
Q

ALADA:

A

As Low As Diagnostically Acceptable

173
Q

Why was ALADA created as a a variation of ALARA by Dr. Jerald Bushberg in 2014?

A

To emphasize the importance of optimization in medical imaging

basically telling these dum ass mf ers to watch they selves

174
Q

Dose reduction mechanisms in relation to the X-ray tube head include: (2)

A
  1. filtration
  2. collimation
175
Q

Selective passage of contents through a specified substance:

A

filtration

176
Q

Selectively removes a greater proportion of low keV x-ray photons:

A

filtration

177
Q

Filtration selectively removes a greater proportion of:

A

low keV x-ray photons

178
Q

When filtration selectively removes a greater proportion of low keV x-ray photons, this results in:

A

increased mean energy of the beam (because its only keeping high keV)

179
Q

What dose reduction x-ray mechanisms in relation to the X-ray tube head increases the mean energy of the beam?

A

filtration

180
Q

In regard to filtration, most of the units are ___ kV.

A

60kV

181
Q

In regard to filtration, a higher kv means:

A

better image quality (but more expensive and requires more filtration)

182
Q

Collimation describes the:

A

shape & size of the beam

183
Q

In regard to collimation, what shape of beam is preferred?

A

rectangular

184
Q

In regard to collimation, what is the maximum diameter for intraoral radiation?

A

2.75” (exit-side beam collimation)

185
Q

What are the MANDATED requirements for the X-ray tube head?

A
  1. filtration
  2. collimation
186
Q

a ____ collimator is an OPTIONAL dose reduction mechanism

A

rectangular

187
Q

The area exposed is related to:

A

the maximum size of the beam

188
Q
  • tru-align
  • tru-image
  • universal rectangular collimator

These are all types of:

A

rectangular collimators

189
Q

____ is reflective of the specific technique for common exams

A

effective dose

190
Q

(optional) A high kV generator/ transformer allows for a ____

A

lower dose of radiation

191
Q

Higher kV units are: (2)

A

larger & heavier

192
Q
  1. rectangular collimator
  2. higher kV generator
  3. constant potential (DC) fully-rectified
  4. increased focal lenght

These are all:

A

OPTIONAL X-ray tube head dose reduction mechanisms

193
Q

Discuss how increased of long BID benefits the patient: (3)

A
  1. 27% less head volume
  2. reduced effective dose
  3. sharper image
194
Q

Dose reduction mechanisms PRACTICE OPTIONS include: (4)

A
  1. film speed
  2. lead PB thyroid color
  3. film-holding devices with beam alignment capablity
  4. time-temperature quality control processing
195
Q

Film speed includes-

D:
E:
F:

A

D speed: ultraspeed
E speed: ektaspeed
F speed: insight

196
Q

List the types of digital receptors that contribute to film speed:

A
  1. PSPP (photostimulable phosphor plate)
  2. CCD (charge coupled device)
  3. CMOS (complimentary metal oxide semiconductors)
197
Q

Of the types of digital receptors, which is the most radiation sensitive:

A

CCD (lowest dose)

198
Q

Of the types of digital receptors, which is the most common?

A

CMOS

199
Q

In regard to image detector speed, the faster the receptor, the ____ the patient exposure

A

less

200
Q

What is the #1 way to reduce patient exposure?

A

using a faster receptor

201
Q

Film is the ____ receptor but produces the ____ image

A

slowest; sharpest

202
Q
  • Doesn’t come in an alternating current rather allows a constant potential causing the patient to be LESS exposed because you are ALWAYS producing x-rays so it is more time efficient (faster with less tie exposing patient)
A

Rectification

203
Q

X-ray tube head circuitry only producing high energy photons that are good for image production and safer for the patient:

A

Rectification

204
Q

What are two important means of patient protection?

A
  1. thyroid collar
  2. lead apron
205
Q

Discuss the total filtration required for the following:

operating kv of less than 50:

operating kv 50-70:

operating kv of greater than 70:

A

<50 kV capability= 0.5mm aluminum filter

50-70 kV capability= 1.5mm aluminum filter

> 70 kV capability = 2.5 mm aluminum filter

206
Q

During an exposure taken with a wall mounted x-ray unit, the operator should stand:

A

behind a barrier/wall

207
Q

During an exposure taken with a wall mounted x-ray unit, where should the operator stand if no protective barrier/wall is present:

A

Atleast 6 feet away at an angle betweenT/ 90-135 degrees to the direction of the useful beam (primary beam)

208
Q

T/F: It is acceptable to stand in the primary beam of the x-ray when absolutely needed:

A

False- NEVER stand in the primary beam

209
Q

T/F: As an x-ray operator, you should NEVER hold the film or other receptors in a patients mouth

A

true

210
Q

T/F: Radiation monitoring badges are optional

A

true (but they are recommended)

211
Q

When are dosimeter badges worn?

A

dosimeter badges will be worn by a full-time operator of radiographic equipment while x-ray exposures are being made (these are optional but recommended)

212
Q

An occupational whole body exposure will not exceed:

A

50 mSv

213
Q

Operators who have declared pregnancy will not exceed more than ____ to the embryo or fetus during the term of the pregnancy

A

5 mSv

214
Q

What are the nomad and nomad pro?

A

self-contained, hand-held portable x-ray units

215
Q

T/F: The use of the nomad x-ray unit violates current radiology statutes

A

True

216
Q

What statutes does the nomad x-ray unit violate?

A

“during each exposure, operator should stand at least 6 feet from patient or behind a protective barrier”

“neither the tube housing nor the position indicating device (cone, cylinder) should be hand-held during the exposure”

217
Q

What the are the exemptions for licensed hand-held units?

A
  1. a backscatter shield must be permanently mounted to the cone and used at all times
  2. operators must wear a personnel monitoring device that must be evaluated monthly
  3. all personnel must use training in the use of these x-ray systems and records of the training kept for review
218
Q

Label the arrows:

A

top left: back scatter shield
bottom left: end of PID
top right: control panel
bottom right: battery (entire handle)
middle: trigger

219
Q

When using a nomad, where should the backscatter shield be placed?

A

at the end of the PID (closest to the patient)

220
Q

When using a nomad, where should the PID be aligned?

A

align PID close to the patient

221
Q

Radiation protection AKA:

A

dose reduction methods

222
Q

What is the BEST way to protect patient from radiographic exposure?

A

Don’t take radiographs at all

223
Q

What does the “cerebral option” mean?

A

Not every patient needs the same radiographs every time

224
Q

According to the cerebral option, who are NOT candidates for dental radiographs:

A

low caries patients, with good oral hygiene, and no concerns of oral disease

225
Q

You should never exposure the patient just for:

A

updating records

226
Q

Reduce the number of radiographs by: (3)

A
  1. collection of patient data
  2. assimilation of facts
  3. critical thinking to arrive at a decision
227
Q

The selection criteria guidelines for radiographs are supported and developed by:

A
  1. FDI
  2. FDA/ADA
228
Q

FDI indications for imaging states: You need a specific ____ or a ___ task that a radiographic image will produce unique information not readily available from other from other diagnostic means

A

question; diagnostic task

229
Q

What entity states “You need a specific question or a diagnostic task that a radiographic image will produce unique information not readily available from other from other diagnostic means”

and “imaging requires justification”

A

FDI

230
Q

According to the FDI’s indications for imaging, what is required prior to taking radiographs?

A

an initial clinical exam is required to make the assessment that they need a radiograph; most regulatory agencies require this

231
Q

FDA radiograph guidelines were created in ____ and revised in ___, ___.

A

1987; 2004; 2012

232
Q

Selection criteria according to the FDA/ADA: (2)

A
  1. follows recommendations of FDI
  2. specific need to supplement clinical information
233
Q

Individualized radiographic exam consisting of selected periapical/occlusal views and/or posterior bitewings if proximal surfaces cannot be visualized or probed.

Patients without evidence of disease and with open proximal contacts may not require a radiographic exam at this time:

A

Child with primary dentition- New patient

234
Q

Posterior bitewings exam at 6-12 month intervals if proximal surfaces cannot be examined visually or with a probe:

A

Child with primary dentition or Child with transitional dentition or Adolescent with permanent dentition- Recall patient (high risk)

235
Q

Posterior bitewing exam at 12-24 month intervals if proximal surfaces cannot be examined visually or with a probe:

A

Child with primary dentition or Child with transitional dentition- Recall patient (no increased risk)

236
Q

Individualized radiographic exam consisting of posterior bitewings with panoramic exam or posterior bitewings and selected periapical images:

A

Child with transitional dentition- new patient

237
Q

Individualized radiographic exam consisting of posterior bitewings with pano or posterior bitewings with selected periapical images.

A FMX is preferred when the patient has clinical evidence of generalized oral disease a history of extensive dental treatment

A

adolescent with permanent dentition- new patient

238
Q

Posterior bitewings exam at 6-18 month intervals:

A

adult dentate or partially edentulous - recall patient (high risk)

239
Q

Posterior bitewing exam at 18-36 month intervals:

A

adolescent with permanent dentition- recall patient (Not high risk)

240
Q

Posterior bitewing exam at 24-36 month intervals:

A

adult dentate or partially edentulous- recall patient (not high risk)

241
Q

Individualized radiographic exam, based on clinical signs and symptoms-

A

adult edentulous- new patient

242
Q

Clinical situations for which radiographs may be indicated include, but are not limited to: (2)

A
  1. positive historical findings
  2. positive clinical signs and symptoms
243
Q

Occlusal radiography requires:

A

Phosphor plate film

244
Q

What size of sensory is used for occlusal radiography?

A

2 for child and #4 for adult

245
Q

What are the types of occlusal radiographies in the maxilla?

A
  1. standard cross-sectional
  2. lateral (right/left) cross-sectional
  3. anterior topographical
246
Q

What are the types of occlusal radiographies in the mandible?

A
  1. standard cross-sectional
  2. lateral (right/left) cross-sectional
  3. anterior topographical
247
Q

For standard cross-sectional maxilla, the vertical angle is:

The central ray (CR) is at the:

A

+ 65-70 degrees (pointed downward)

bridge of nose and center of PSP plate

248
Q

This image shows:

A

standard cross-sectional maxillary occlusal radiography

249
Q

A true cross section=

A

perpendicular image

250
Q

What features of the palate can be seen with a standard cross-sectional maxillary occlusal radiograph?

A

entire palate

251
Q

This image shows what type of radiograph?

A

standard cross-sectional maxillary occlusal radiography

252
Q

For lateral cross-sectional maxillary, the vertical angle is:

The central ray (CR) is at the:

A

vertical angle: + 55-60 (pointed downwards)

central ray: posterior maxillary

253
Q

What does this image show?

A

lateral cross-sectional maxillary occlusal radiography

254
Q

This image shows what type of radiograph?

A

lateral cross-sectional maxillary occlusal radiograph

255
Q

For anterior topographical maxillary, the vertical angle is:

The central ray (CR) is at the:

A

+ 55-60 degrees (pointed downward)

Central ray: 1/4 to 1/2 inches above the tip of the tip of nose

256
Q

What does this image show?

A

anterior topographical maxillary occlusal radiography

257
Q

This image shows what type of radiograph?

A

anterior topographical maxillary occlusal radiograph

258
Q

For standard cross-sectional mandibular, the vertical angle is:

The central ray (CR) is at the:

A

perpendicular to PSP

Central ray: between mandibular first molars; along mid-sagittal plane

259
Q

What does this image show?

A

standard cross-sectional mandibular occlusal radiography

260
Q

For lateral cross-sectional mandibular, the vertical angle is:

The central ray (CR) is at the:

A

perpendicular to PSP Plate following long axis of first of first molar

Central ray: center of PSP plate @ apex of first molar

261
Q

For anterior topographical mandibular, the vertical angle is:

The central ray (CR) is at the:

A
  • 55 to 60 degrees (pointed upward); bisecting angle between PSP plate and long axis of incisor teeth

Central ray: below apices of incisors, 1 cm above tip of chin, along midline of chin, directed at center of PSP plate

262
Q

How occlusal exposure settings when compared to posterior maxillary periapical exposures?

A

1 (or possible 2) exposure settings higher

263
Q
  • orthodontic encaluations
  • orthognathic evaluations
  • pathology beyond coverage of standard dental images

These are all indications for:

A

skull radiography

264
Q

What are the skull projections in skull radiography (5)?

A
  1. lateral cephalogram/cephalometric
  2. PA cephalogram/cephalometric
  3. waters’ PA
  4. Reverse-towne (PA)
  5. SMV
265
Q

What are the image enhancers for skull radiography?

A
  1. grids (standard, focus, grid ratios)
  2. air gaps
266
Q

Reduce amount of scatter radiation exposing film and improves image contrast:

A

grids with PSPP

267
Q

What do grids do in skull radiography?

A

block the scatter photons

268
Q

What does increasing the tube-to-object distance do for skull radiography?

A

Improves image sharpness

269
Q

A lateral cephalogram will identify:

A
  1. maxillary sinus
  2. frontal sinus
  3. sphenoid sinus
270
Q

Cephalometric radiography is different because there is a filter to:

A

capture soft tissue

Oral Radiology (21 decks)

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