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Tim's Cards > Radiology I > Flashcards

Radiology I Flashcards

1
Q

Radiation is the transmission of energy through space and matter and occurs in what 2 forms?

A

Particulate

Electromagnetic

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2
Q

Radioactivity releases alpha or beta particles or gamma rays generated where?

A

Inside the nucleus

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3
Q

Oral and maxilofacial radiology involves only what type of radiation?

A

Electromagnetic

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4
Q

What type of radiation in the electromagnetic spectrum is capable of ionizing matter?

A

High energy (UV and up)

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5
Q

T/F

Electromagnetic radiation is generated when the velocity of an electrically charged particle is altered

A

True

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6
Q

The energy of dental x-rays is 60k to 90 kā€¦. (unit?)

A

eV

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7
Q

The x-ray tube is surrounded by insulating material, usually what?

A

oil

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8
Q

The X-ray tube has electrons stream from the ______ to target the ______.

A

Cathode

Anode

*energy from some e- is converted into x-rays

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9
Q

The Filament (the source of electrons within an x-ray tube) is a coil of ______ wire.

The Focusing Cup is a negatively charged concave reflector of ________ surrounding the Filament.

A

Tungsten

Molybdenum

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10
Q

The Anode is a ______ target embedded in copper

A

Tungsten

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11
Q

The sharpness of an x-ray image ________ as the size of the focal spot Decreases.

A

Increases

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12
Q

What type of Radiation primarily emanates from an x-ray tube?

A

Bremsstrahlung Radiation

*German for ā€œbraking radiationā€

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13
Q

Bremsstrahlung Radiation generates x-ray photons with a continuous spectrum of energy and the beam is usually described by its peak operating voltage which is what?

A

70 kVp

*so, fluctuated up to 70

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14
Q

The exposure time of an x-ray takes how long?

*time is directly proportional to photon exposure

A

fractions of second

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15
Q

The number of photos that reach the patient and image receptor is directly proportional to what 2 things?

A

current (mA)

time (s)

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16
Q

Beam quantity/intensity refers to what?

A

Number of photons in x-ray beam

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17
Q

What factor is related to the Tube Voltage Peak (kVp)?

A

Quality (meaning energy of x-ray beam)

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18
Q

Increasing the kVp of an x-ray increases what 3 things?

A

photons

mean energy of those photons

maximal energy of photons

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19
Q

T/F
Low energy photons that canā€™t reach the receptor still might do damage to the patient and these can be removed by a filter

A

True

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20
Q

There is inherent filtration the x-ray passes through like glass, oil, etc. as passes through the machine, but what kind of filter preferentially removes low Energy photons?

A

Aluminum

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21
Q

T/F

The Collimator is a metallic barrier used to restrict x-ray size and is Round or Rectangular

A

True

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22
Q

The Collimator improves the image quality by decreasing what?

A

Scattered Radiation produced by absorbed photons

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23
Q

Describe the Inverse Square Law that applies to x-ray beams.

A

Double distance, intensity of beam is now 1/4

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24
Q

X-rays have an Incident Beam, Attenuation, and Scatter - what are the 3 types of Attenuation?

A

Coherent Scatter 7%

Photoelectric absorption 27%

Compton scattering 57%

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25
Q

A Coherent Scatter is the change in direction of a photon, a Compton Scatter involved both a ______, like Photoelectric Absorption, and a scattered photon of _____ energy

A

Recoil Electron

Lower

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26
Q

T/F
Different tissues have different Radiosensitivities, so effective dose is a calculation of radiation type and tissue type to determine risk of cancerous formation

A

True

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27
Q

X-rays travel at the speed of light and have no ______ and no ______

A

mass

charge

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28
Q

T/F

X-rays cause fluorescence and ionization

A

True

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29
Q

T/F

Males have a higher chance of developing cancer throughout life

A

True

44% vs 37%

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30
Q

Ionizing Radiation is able to remove what?

A

Orbital e- from atoms

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31
Q

Radiation exposure is measured in what?

A

Roentgen (R)

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32
Q

What is used to compare the biologic effects of different types of Radiation?

unit?

A

Equivalent dose = REM - roentgen equivalent man

Sievert (Sv) = 100 rems

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33
Q

T/F
The Effective dose expresses radiation risk to the whole body even though whole body was not exposed and sums the Equivalent dose to each tissue/organ and a tissue weighting factor

A

True

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34
Q

T/F

The amount of radiation on the skin (Skin Entrance Dose) is the same as the Effective Dose

A

False

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35
Q

The amount of radiation incident on an organ:

Radiation absorbed by tissue:

Biological comparison of different Radiation types on different Tissues:

A

Organ dose

Absorbed dose

Equivalent dose

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36
Q

What dose is used to estimate radiation risks, compares radiosensitivities, weighting factors and is calculated in Sieverts?

A

Effective Dose

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37
Q

T/F

Salivary Glands are highly Radiosensitive

A

False

  • down around skin
  • *bone marrow highest
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38
Q

Example of a Direct radiation effect:

Example of an Indirect radiation effect:

A

alters structure/function of molecule ***(1/3)

water ionization - free radical ionization

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39
Q

Indirect Attack causes ____ of DNA damage

A

2/3

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40
Q

The cell killing is Dental Radiography can be described asā€¦

A

negligible

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41
Q

T/F

The primary risk from dental radiography is the unlikely chance of radiation-induced cancer

A

True

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42
Q

What are the critical organs affected by Radiation?

3

A

Bone Marrow

gonads

Thyroid

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43
Q

The Effective Dose, based on tissue type, is measured in what?

A

Sieverts

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44
Q

Deterministic effects are caused by Lethal DNA damage and cell death, while Stochastic effects are based on what?

A

Gene mutation

*leukemia, thyroid cancer, etc

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45
Q

Bone marrow, testes, _____, ______, and _____ are highly radiosensitive organs.

A

Lymphoid organs

Intestines

Mucous membranes

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46
Q

T/F

Neurons and muscle have Low Radiosensitivity

A

True

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47
Q

Radiation is a weak mutagen and there is no evidence for a dose ______

A

Threshold

*damage possible at any dose

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48
Q

T/F

Germ cell mutations arising from radiation are possible, but have not been observed in humans

A

True

*Hiroshima/Nagasaki didnā€™t pass on defects

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49
Q

T/F

Radiation might activate latent carcinogenic viruses or create conditions that favor tumor growth

A

True

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50
Q

The most radiosensitive cells tend to have high mitotic rates, undergo many future mitoses, and are the most primitive in differentiation.

What are the two exceptions?

A

Small lymphocytes

Oocytes

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51
Q

The most radiosensitive tissue is Bone Marrow, what is the least?

A

Nerve cells

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52
Q

Cells are most radiosensitive at mitosis and least sensitive during what phase?

A

Late S

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53
Q

The average energy released from ionization and excitation to absorbing medium per unit track length:

*most widely used term for comparisons of the quality of different radiations

A

Linear Energy Transfer (LET)

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54
Q

X-rays have ___ LET, while Alpha particles and Neutrons have ____ LET

A

low

high

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55
Q

T/F

High LET radiation tends to generate clustered DNA damage, while low LET radiation creates isolated lesions on DNA

A

True

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56
Q

100 Gy, death in 1 to 2 days by:

10 Gy, death in 5-10 days by:

2-5 Gy, death in 3 weeks by:

A

cerebrovascular syndrome

GI syndrome

Hematopoietic syndrome

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57
Q

2 Gy exposure will result in Transient ______ in hours and last 1 -2 weeks

A

Erythema

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58
Q

focused 10 Gy can result in Dry _______

above 15 Gy ______

A

Desquamation

Moist Desquamation

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59
Q

When during a lifetime is cancer more likely to be fatal?

A

Early

*changes around 30

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60
Q

T/F

A fetal dose of radiation can double cancer rates

A

True

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61
Q

T/F

Dental radiographs have a scatter dose to a fetus that is indistinguishable from background radiation

A

True

*therefore, cannot produce birth defects (this is motivated reasoning, but whatever)

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62
Q

Rectangular Collimation can decrease the radiation dose by how much?

A

90%

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63
Q

What is the term that expresses the ā€œone in a millionā€ chance of things?

A

Micromort

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64
Q

Dental x-rays are ___ mrem

NY to Cal flight ___ mrem

background radiation ___ mrem/yr

A

3

5

300

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65
Q

Long plane flight = 1 Micromort

The average man in his 50ā€™s has a ____ micromort day risk

Average woman in her 50ā€™s has ___ micromort day

A
  1. 1

1. 3

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66
Q

400 million x-rays taken/year in the US, How many dental?

A

100 million

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67
Q

Of all the Ionizing Radiation a person receives a year in the US about ____ is background and ____ is medical

What % is Dental?

A

half

half

2.5%

68
Q

Because the effects of ionizing radiation at low doses are not fully understood, what concept is invoked?

A

ALARA

as low as reasonably achievable

69
Q

What is the Maximum permissible dose of whole body radiation/year?

Lens of eyes?

All other specific areas of the body?

A

50 mSv

150 mSv

500 mSv

70
Q

T/F

The MAD - maxi accumulated dose is 10 mSv x Age

71
Q

F speed film reduces radiation by:

Rectangular Collimation reduces dose by:

72
Q

Exposures should use Thyroid Collars and be at w/ _______ kVp

73
Q

T/F

The image receptor holding device is more accurate and reduces image retakes

74
Q

Aluminum absorbs low energy photons, what absorbs highest and lowest energy?

A

Rare earth metals

75
Q

T/F

The focal spot receptor distance can reduce skin dose when moving closer

76
Q

What distance should personnel be from the radiation source?

A

6 feet

*behind lead glass window or mirror

77
Q

Large pts increase exposure time by ___%

Small/child/edentulous pts decrease by ___%

78
Q

Intensity = 1/D squared

A

Inverse Square Law

79
Q

What is the Maximum Allowable radiation dosage from diagnostic radiography?

80
Q

T/F

A Lithium fluoride crystal can be used as a Personnel Monitoring Device

81
Q

T/F

Rapid and accurate diagnosis is usually most beneficial to the patient

82
Q

The average medium FOV CBCT scan carries a ____ micromort risk

83
Q

Potential risk to a fetus is _______

Fetal exposure is entirely ______

A

childhood cancer

indirect

84
Q

T/F

Pregnancy is a Contraindication to diagnostic radiography

85
Q

Dental radiographic images contribute to _____% of total Exposure from medical imaging

A
  1. 26%

* despite being 1/4 of all medical imaging

86
Q

5 hr airline flight = 25 uSv or ___ pan and ___ BWā€™s

A

1 pan

2 BWā€™s

87
Q

Average occupational radiation dose is ___% of allowable exposure

88
Q

T/F

There are no limits on the exposure a pt can receive from diagnostics, etc

89
Q

1 byte = ___ bits

90
Q

The grayscale puts black at 0 and white at _____

91
Q

The bit scale is:

bit depth, gray scale

A

exponential

92
Q

What are the 2 types of resolution in Digital imaging?

A

Spatial - pixels, dpi, etc

Contrast - how many shades

93
Q

Aside from Spatial and Contrast resolution, the ____ also must have good resolution in digital imaging

94
Q

What are the 2 types of Digital Detectors?

A

Solid State

Photostimulable Phosphor (PSP)

95
Q

CCD and CMOS sensors are what type?

A

Solid State

96
Q

Intraoral CCD is ____, while intraoral CMOS is ____

A

wired

wireless

97
Q

T/F

Extraoral Solid State detectors can be Digital Direct, Panoramic, or Cephalometric sensors

98
Q

T/F

PSP, Photostimulable Phosphor are the same size as film and disposable

A

False

100% re-usable

99
Q

In Storage Phosphor Technology, the Latent Image produced on the plate goes through what?

***definitely on test

A

Red Laser Scan

100
Q

The latent image on a ______ can be erased and 100% re-used.

A

PSP - Photostimulable Phosphor

101
Q

PSP cycle: Acquisition, ______, view, erase, hygiene

A

Laser Scanning

102
Q

The advantage to CCD/CMOS (solid state) over PSP is what?

A

Direct image

103
Q

The advantage of PSP over CCD/CMOS are what 3 things?

A

Film-like

Large exposure latitude

Cheap plates

104
Q

T/F

Brightness, Contrast, and Gamma adjustment are types of Digital Processing to enhance image

105
Q

T/F

LUT inversio, Color conversion, and Embossing are all considered ā€œtoysā€ and arenā€™t real image enhancement

106
Q

T/F

Resolution is not that important for detecting dentoalveolar disease, contrast and density play a much larger role.

107
Q

T/F

Most systems have more resolution than the human eye can detect

108
Q

The Sensor Resolution is ____ Microns (XIOS Plus)

109
Q

In X-ray film, the ______ is sensitive to x-rays and visible light, and the _____ supports it.

A

Emulsion

Base

110
Q

Emulsion is composed of what?

A

Silver halide/bromide

111
Q

Direct Exposure Film is exposed by X-rays, _____ film is used with intensifying screens and extraoral projections

This type of film is sensitive to what?

A

Screen film

Visible light (and x-ray)

112
Q

How would you know if X-ray film is loaded backwards?

A

Lead film on back casts pattern and image is light

113
Q

In an Intensifying Screen, what causes visible light from x-rays?

A

Inorganic salts/phosphors

114
Q

***The use of Intensifying Screen has what effect on patients?

A

REDUCES dose of x radiation

115
Q

Developer, water bath, fixer, water, dry

A

Film processing

116
Q

The _____ converts silver bromide crystals with neutral silver atoms deposited at latent image sites into black, solid silver metallic grains

117
Q

What removes unexposed, undeveloped silver bromide crystals, leaving the film clear in unexposed areas?

118
Q

Light, radiopaque areas means:

Dard, radiolucent areas means:

A

few photons reached film

many photons reached film

119
Q

Film that is too light can mean what?

Film that is too dark?

A

underexposed

overexposed

120
Q

T/F

Spots on film can be from faulty processing, blurred can be caused by pt. movement

121
Q

Sharpness can be increased with a small focal spot, increasing distance between _____, and minimizing distance between ______

A

focal spot and object

object and image receptor

122
Q

Foreshortening can be caused by not aligning with the _____.

Elongation can be caused by not aligning with the ______

A

tooth (or other object)

film/plate

123
Q

What technique minimizes distortion?

A

Paralleling

124
Q

In a tube shift or dual image technique what rule determines where objects are in relation to one another?

A

SLOB

Same Lingual, Opposite Buccal

125
Q

Mesial shift, object moves mesially:

Mesial shift, object moves distally:

A

Lingual side

Buccal side

126
Q

Eggshell effect:

A

rim is radiopaque (3D effect)

127
Q

The backbone of imaging for the general dentist is Intraoral Radiographic, what are the 3 Categories?

A

Periapical (PA)

Bitewing (BW)

Occlusal

128
Q

A Full Mouth (FMX) or Complete Mouth Series (CMS) consists of what?

A

PAā€™s, BWā€™s, and 18 images

129
Q

T/F

The use of correct imaging modalities often excludes cone beam CT, etc

A

True

*used intraoral imaging instead

130
Q

What are the drawbacks to Panoramic imaging?

A

Resolution

Large field of view

131
Q

What are the drawbacks to cone beam CT (CBCT)?

4

A

Cost

Dose

restoration interference

artifacts

132
Q

T/F

Overlap can be caused by bad angulation of the Tube Head

133
Q

What method may be useful when the operator is unable to apply paralleling technique for whatever reason?

A

Bisecting Angle Technique

134
Q

T/F

Position the tube head to the side of the pt that will be radiographed

135
Q

The open end of the cylinder must be ____ with the guide ring

136
Q

What are the 6 Rules for Intraoral Imaging

(principles of Dental Imaging)?

A

Receptor completely covers teeth

Vertical sides of receptor parallel with long axes of teeth

Horizontal sided of receptor parallel with horizontal plane of teeth

Open end cylinder parallel with receptor

Central ray enters Proximal Embrasure at 90 degrees

Central ray directed at center of Receptor

137
Q

When are Vertical Bitewings used?

A

Perio disease

*alveolar crest more apical

138
Q

T/F
Occlusal Radiographs can see more structures, are used if pt canā€™t open mouth, can determine locus, and are limited by receptor size

139
Q

What force carrier particle makes up the x-ray beam?

140
Q

What has greater energy than x-rays?

141
Q

Quantum Theory of radiation has been successful in correlating experimental data of what?

A

Production of X-rays

***polarization, refraction, diffraction all wrong

142
Q

What % of the kinetic energy of e- that hit the anode are converted to heat?

143
Q

Increasing the kVp does what 2 things?

A

Increases # photons and Mean Energy

144
Q

What is the primary means of dental x-ray attenuation?

A

Thickness of the mass and energy of the beam

145
Q

What is the most common type of scattering?

146
Q

When lower energy photons are removed by aluminum filtration, the mean energy ____, and the beam intensity _____.

A

increases

decreases

147
Q

Deterministic effects have a ______

Stochastic effects have no _____

A

threshold

threshold

148
Q

What tissue type of the Oral Mucosa is particularly Radiosensitive?

A

Basal cells

149
Q

In a child, radiation therapy may destroy what (esp if combined with chemo)

A

Tooth buds

150
Q

If a pt has head/neck therapy avoid intraoral radiographs for how long?

151
Q

What organ has the lowest susceptibility to induced cancer?

A

Salivary Glands

152
Q

Most of the radiation the worldā€™s population is exposed to comes from what?

153
Q

Dental x-rays account for less than 1% of the average daily human exposure.

154
Q

E/F speed is faster than D speed, what has more quality?

155
Q

State regs require the x-ray beams to be _______ cm or ______ inches to the pts skin surface.

A

7 cm

2 3/4 inches

156
Q

What size dental films is normally used for adult bitewings?

157
Q

How long can a safe light be used in a dark room before it affects the picture?

158
Q

Increasing the focal spot of the film distance does what?

A

Decreases film density

159
Q

What makes up the Antral Y?

A

Maxillary sinus and the floor of the nasal cavity

160
Q

What is above the Maxillary molars on a radiograph?

A

Maxillary sinus

161
Q

A ā€œUā€ shape on every board exam is what?

A

Zygomatic process

162
Q

T/F

The Hamulus will be at the same level as the molars

163
Q

Striations through the Maxillary sinus are what?

A

Blood vessels in lateral wall

164
Q

Ridges on the top of the palate:

A

Torus palatinus

165
Q

Inferior nasal cavity bone

A

Inferior turbinate

Tim's Cards (140 decks)

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