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Oral Radiology > Exam 2 Study Guide > Flashcards

Exam 2 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 we refer to as:

A

Penumbra

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6
Q

Three factors that affect the quality of the radiograph:

A
  1. image sharpness
  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

Improperalignment/ANGULATION of receptor, object and beam

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14
Q

Three 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= greater sharpness because there are fewer photons interacting with the object)

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16
Q

Smaller focal spot= _____ sharpness

A

greater sharpness

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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 mechanism 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 image sharpness:

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; decreased divergence

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22
Q

Discuss the object-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 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

Two 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 two ways to minimize shape distortion:

A
  1. object and receptor should be PARALLEL
  2. Beam should be PERPENDICULAR 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 PERPENDICULAR to object and receptor

A

Minimized shape distortion

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32
Q

List the five 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) & receptor
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33
Q

The five 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 “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? And how?

A

Increased 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

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

A

The 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 & 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 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 traverse 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 and 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 effect biologic structure, function 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 X-rays 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 anatomic area of interest form the:

A

Latent image

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74
Q

Measure of the biological effectiveness of a radiation to ionize matter:

A

QF

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75
Q

Have 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 proportional 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

genetic mutations that cause 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 & thyroid cancer

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82
Q

Direct radiation effects on cellular structures is caused by:

A

Rupture in the cell wall of a biologically active molecule

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83
Q

What factor effects radiosensitivity to the greatest degree?

A

Age

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84
Q

Children aged _____ are _____x more likely of radiation induced cancer

A

2-10; 2-6x

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85
Q

Radiation induced tissue 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:

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 200R, Less than 2Gy

Non-lethal

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88
Q

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

A

Prodromal period

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89
Q

Describe the prodromal period of acute radiation syndrome:

A

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

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90
Q

Discuss 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

200-1000R, 2-10Gy

Lethal

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92
Q

Irreversible injury to the proliferative capacity 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 ____ & _____. 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, 10-100Gy

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 ____ & _____ 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

Supra lethal

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100
Q

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

A

CNS & CV syndrome

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101
Q

Describe the timeline with CNS & CV sun from of acute radiation syndrome:

A

Irreversible damage with death in a few minutes to 48 hours

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102
Q

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

Solid tumors=

Lymphomas=

Intraoral 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 (20)=

Pano=

A

single intraoral radiograph= 1.3 mSv

FMX (20)= 33 mSv

Pano= 9 mSv

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106
Q

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

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

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

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

Oral tissues are subjected to high doses of radiation during treatment of malignant tumors of the soft palate, tonsils, floor of mouth, nasopharynx, hypopharynx.

This can have effects on the:

A

Oral mucosa, tastebuds, salivary glands, teeth, bone, and muscle

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108
Q

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

A

Loss of taste (Hypogeusia)

110
Q

What results in loss of taste to 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 to 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 of 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 months to 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 to 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 are replaced by fibrosis & adiposis:

A

Parenchymal cells; parotid glands

119
Q

Parencymal 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 caries 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

T/F: There is a discernible effect on 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 developmental 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 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 mechanism 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

200 R; 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 & bone marrow (affecting vascular & hematopoietic 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 & inflammation that occur in the muscle in the muscle from dental ionizing radiation results in:

A

contracture & trismus in the muscle

135
Q

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

Medical= __ mSv

Natural= ___ mSv

Other (man-made)= ____

A

3.2 mSv

3 mSv

0.1 mSv

136
Q

-Consumer products (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 man-made exposure of background ionizing radiation=

A

Medical imaging (greater than 50%)

139
Q

The majority of natural exposure of background ionizing radiation=

A

Radon (around 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 to 6.2 mSv

142
Q

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

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

Explain the following:

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

A

1 way to reduce exposure

Faster the receptor type, the less patient exposure

144
Q

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

A

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

145
Q

Explain the following:

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

A

BW, Pano, PA, CBCT, etc.

146
Q

Explain the following:

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

A

Rectangular collimator with 2.75” diameter preferred

147
Q

Explain the following:

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

A

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

148
Q

MPD:

A

Maximum permissible dose

149
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)

150
Q

The MPD occupational limits:

A

5 Rem/year (5000 mRem)

*50 mSv

151
Q

The average dental personal exposure to radiation:

A

0.2 mSv

152
Q

The MPD non-occupational limits:

A

0.5 Rem/year (500 mRem)

153
Q

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

A

3.6 mSv

154
Q

The MPD pregnant occupational limits:

A

0.5 Rem/year (500 mRem)

*5 mSv at 9 months
*0.5 mSv at 1 month

155
Q

In what population are radiographs indicated for acute painful dental problems only when outweighing risk vs. benefit:

A

Pregnant women

156
Q

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

A

Thyroid cancers & leukemia

157
Q

What is the THRESHOLD radiation erythema dose?

A

250 Rads

158
Q

What is the AVERAGE radiation erythema dose?

A

500 Rads

159
Q

What is the MAXIMUM radiation erythema dose?

A

700 Rads (1st degree burn)

160
Q

In 1959 how many exposures were required to cause TED?

A

62 exposures (1250/20)

161
Q

in 2023, 1/3 of TED is delivered with ~ ______ intraoral dental exposures at a _____ focal distance

A

298; 8”

162
Q

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

A

Doubled (16”)

~473 exposures

163
Q

Benefits of dental radiography include:

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 IAC
  8. anatomy assessment for implants
  9. calculus
164
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 & 94% interproximal decay)

165
Q

20% incidence in asian & Chinese populations & 10-12% incidence in native North American populations

A

a lingual root of mandibular first molars

166
Q

Basal bone pathology in jaws:

Hyperdontia is most common in the ____ area

A

premolar

167
Q

What are the goals for maxillofacial & oral radiology?

A
  1. reduce radiation exposure
  2. maintain a high degree of diagnostic efficiency
168
Q

It is a juggling act to:

A

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

169
Q

ALARA:

A

As Low As Reasonably Achievable

170
Q

A guiding principle of radiation protection:

A

ALARA & ALADA

171
Q

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

A

Receiving even the smallest dose of unnecessary radiation

172
Q

With ALARA, what was prioritized?

A
  1. time
  2. distance
  3. shielding factors
173
Q

ALADA:

A

As Low As Diagnostically Acceptable

174
Q

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

A

to emphasize the importance of optimization in medical imaging

175
Q

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

A
  1. filtration
  2. collimation
176
Q

Selective passage of contents through a specified substance:

A

Filtration

177
Q

Selectively removes a greater proportion of low keV X-ray photon:

A

Filtration

178
Q

Filtration selectively removes:

A

a greater proportion of low keV X-ray photons

179
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)

180
Q

What does reduction mechanism in relation to the X-ray tube head, increases the mean energy of the beam?

A

Filtration

181
Q

In regard to filtration, most of the units are ____kV

A

60 kV

182
Q

In regard to filtration, a higher kV means:

A

Better image quality (but more expensive & requires more filtration)

183
Q

Collimation describes the:

A

shape & size of the beam

184
Q

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

A

Rectangular

185
Q

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

A

2.75” (exit-side beam collimation)

186
Q

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

A
  1. filtration
  2. collimation
187
Q

A ______ collimator is an OPTIONAL dose-reduction mechanism

A

rectangular

188
Q

The area exposed is related to:

A

the maximum size of the beam

189
Q

-tru-align
-tru-image
-universal rectangular collimator

These are all types of:

A

Rectangular collimators

190
Q

_____ is reflective of the specific technique for common exams

A

effective dose

191
Q

(Optional) high kV generator/transformer is allows for a ______

A

lower dose of radiation

192
Q

Higher kV units are: (2)

A

larger & heavier

193
Q
  1. rectangular collimator
  2. higher kV generator
  3. constant potential (DC) fully rectified
  4. increased focal length

These are all:

A

OPTIONAL X-ray tube head dose-reduction mechanisms

194
Q

Discuss how increased of long BID benefits the patient in regard to exposure: (3)

A
  1. 27% less head volume
  2. reduced effective dose
  3. sharper image
195
Q

Dose reduction mechanisms PRACTICE OPTIONS include:

A
  1. film speed
  2. lead (PB) thyroid collar
  3. film holding devices with beam alignment capability
  4. time-temperature quality control processing
196
Q

Film speed includes-

D:
E:
F:

A

D speed: ultraspeed
E speed: Ektaspeed
F speed: insight

197
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 (complementary metal oxide semiconductors)

198
Q

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

A

CCD (lowest dose)

199
Q

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

A

CMOS

200
Q

In regards to image detector speeds, the faster the receptor, the ______ patient exposure

A

Less

201
Q

What is the #1 way to reduce patient exposure?

A

Using a faster receptor

202
Q

Film is the ____ receptor, but produces the ____ image

A

Slowest; sharpest

203
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 time exposing patient):

A

Rectifications

204
Q

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

A

Rectification

205
Q

What are two important means of patient protection?

A
  1. thyroid collar
  2. lead apron
206
Q

Discuss the total filtration required for the following:

Operating kV of less than 50:

Operating kV of 50-70:

Operating kV of greater than 70:

A

<50 kV capability: 0.5 mm aluminum filter

50-70 kV capability: 1.5 mm aluminum filter

> 70 kV capability: 2.5 mm aluminum filter

207
Q

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

A

Behind a barrier/wall

208
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

At least 6 feet away at an angle between 90-135 degrees to the direction of the useful beam (primary beam)

209
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

210
Q

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

A

True

211
Q

T/F: Radiation monitoring badges are optional

A

True- but they are recommended

212
Q

When are dosimeter badges worn?

A

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

213
Q

An occupational whole body exposure will not exceed:

A

50 mSv

214
Q

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

A

5 mSv

215
Q

What are the Nomad & Nomad Pro?

A

Self-contained, hand-held, portable X-ray units

216
Q

T/F: The use of the Nomad X-ray unit violates current radiology statues

A

True

217
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”

218
Q

What are the exemptions for licensed hand-held units?

A
  1. 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 receive training in the use of these X-ray systems, and records of the training must be kept for review
219
Q

Label the arrows:

A

Top Left: backscatter shield
Bottom Left: End of PID
Top right: control panel
Bottom right: battery (entire handle)
Middle right: trigger

220
Q

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

A

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

221
Q

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

A

Align PID close to the patient

222
Q

Radiation protection AKA:

A

Dose-reduction methods

223
Q

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

A

Don’t take radiographs at all

224
Q

What does the “cerebral option” mean?

A

Not every patient needs the same radiographs every time

225
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 dental disease

226
Q

You should never expose a patient just for:

A

Updating records

227
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
228
Q

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

A
  1. FDI
  2. FDA/ADA
229
Q

FDI indications for imagine states that you need a specific ______ or a ____ task that a radiographic image will provide unique information not readily available form other diagnostic means

A

Question; diagnostic task

230
Q

What entity states:

“you need a specific question or a diagnostic task that a radiographic image will provide unique information not readily available form other diagnostic means”

and

“imaging requires justification”

A

FDI

231
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 assessement that they need a radiograph; most regulatory agencies require this

232
Q

FDA radiograph guidelines created in ____ and revised in ____ & ____

A

1987; 2004; 2012

233
Q

The selection criteria according the FDA/ADA states: (2)

A
  1. follows recommendations of FDI
  2. Specific need to supplement clinical information
234
Q

Individualized radiographic exam consisting of selected periapical/occlusal views and/or posterior bitewings if promiximal surfaces cannot be 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

235
Q

Posterior bitewing 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 - high risk - Recall patient (high risk)

236
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)

237
Q

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

A

Child with transitional dentition - new patient

238
Q

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

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

A

Adolescent with permanent dentition - new patient

239
Q

Posterior bitewing exam at 6-18 month intervals:

A

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

240
Q

Posterior bitewing exam at 18-36 month intervals:

A

Adolescent with permanent dentition- recall patient (not high risk)

241
Q

Posterior bitewing exam at 24-36 month intervals:

A

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

242
Q

Individualized radiographic exam, based on clinical signs an symptoms:

A

Adult edentulous, new patient

243
Q

Clinical situations for which radiographs may be indicated include, but are note limited to:

A
  1. positive historical findings
  2. positive clinical signs and symptoms
244
Q

Occlusal radiography requires:

A

Phosphor Plate film

245
Q

What size of sensor is used for occlusal radiography?

A

2 for child

#4 for adult

246
Q

What are the types of occlusal radiography in the maxilla?

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

What are the types of occlusal radiography in the mandible?

A
  1. standard cross-sectional
  2. lateral (right/left) cross-sectional
  3. anterior topographical
248
Q

For standard cross-sectional maxilla radiography:

The vertical angle is:

The central ray (CR) is at the:

A

+65-70 degrees pointing downward

ridge of nose and center of PSP plate

249
Q

This image shows:

A

Standard cross-sectional maxillary occlusal radiography

250
Q

a true cross section=

A

a perpendicular image

251
Q

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

A

Entire palate

252
Q

This image shows what type of radiograph?

A

Standard cross-sectional maxillary occlusal radiography

253
Q

For lateral cross-sectional maxilla occlusal radiography:

The vertical angle is:

The central ray (CR) is at the:

A

vertical angle= +55-60 degrees (pointed downwards)

Central ray: posterior maxilla

254
Q

What does this image show?

A

lateral cross-sectional maxilla occlusal radiography

255
Q

This image shows what type of radiograph?

A

lateral cross-sectional maxilla occlusal radiograph

256
Q

For anterior topographical maxilla occlusal radiography:

The vertical angle is:

The central ray (CR) is at the:

A

Vertical angle= +55-60 degrees (pointed downward)

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

257
Q

What does this image show?

A

anterior topographical maxilla occlusal radiography

258
Q

This image shows what type of radiograph?

A

anterior topographical maxilla occlusal radiograph

259
Q

For standard cross-sectional mandibular occlusal radiography:

The vertical angle is:

The central ray (CR) is at the:

A

perpendicular to PSP

Between mandibular first molars, along mid-sagittal plane

260
Q

What does this image show?

A

standard cross-sectional mandibular occlusal radiography

261
Q

For lateral cross-sectional mandibular occlusal radiography:

The vertical angle is:

The central ray (CR) is at the:

A

vertical angle= perpendicular to PSP plate following long axis of first molar

central ray= center of PSP plate @ apex of first molar

262
Q

For anterior topographical mandibular occlusal radiography:

The vertical angle is:

The central ray (CR) is at the:

A

vertical angle= -55-60 degrees (pointed upward) bisecting angle between PSP plate and long axis of incisor teeth

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

263
Q

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

A

1 (or possible 2) exposure settings higher

264
Q

-orthodontic evaluations
-orthognathic evalulations
-pathology beyond coverage of standard dental images

These were all indications of:

A

Skull radiography

265
Q

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

A
  1. lateral cephalogram/cephalometric
  2. PA cephalogram/cephalometic
  3. Waters PA
  4. Reverse-Towne (PA)
  5. SMV
266
Q

what are the image enhancers for skull radiography?

A
  1. grids (standard, focused, grid ratios)
  2. air gaps
267
Q

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

A

Grids with PSPP

268
Q

What do grids do in skull radiography?

A

Block the scatter photons

269
Q

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

A

Improves image sharpness

270
Q

A lateral cephalogram will identify:

A
  1. maxillary sinus
  2. frontal sinus
  3. sphenoid sinus
271
Q

Cephalometric radiography is different because there is a filter to:

A

capture soft tissue

272
Q
A

Oral Radiology (21 decks)

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