ROENTGENOLOGY Flashcards

1
Q

the intensity of gamma rays decreased with the distance from the source is increased

A

Inverse Square Law
I=D
Intensity
Distance

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2
Q

smaller focal spot

A

greater resolution of image

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3
Q

Xray tube in dental xray unit is

A

Coolidge

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4
Q

Power supply

A

Tube Current

Tube Voltage

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5
Q

determines the follow of electrons on the cathode

Most recommended:

A

Tube Current

7-15 mA

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6
Q

generates xrays thru electrons

recommended

A

Tube voltage

recommended: 65-70 kVp

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7
Q

transformation is to increase the voltage

A

Step Up

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8
Q

transformation is to control the voltage dose

A

Step Down

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9
Q

stated that the current flowing through a conductor is Equal to the voltage divided by the resistsnce of a conductor

A
Ohm's Law
V= I/R 
Voltage
I= current
R= resistance
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10
Q

Proper kv for dental films is influenced by

A

Density of the tissue

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11
Q

main fx that influences the time of film exposure

A

Voltage

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12
Q

result from the electrons interacting with nuclei

A

Bremsstrahlung (breaking)

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13
Q

excess radiation

A

Characterisitic

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14
Q

when photons collides with loosely bound in outer shell of an atom

A

Compton (62%)

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15
Q

is produced within thr px through compton interaction

A

Scatter radiation

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16
Q

removes 100% scatter radiatiom to the px

A

Grid

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17
Q

when there is ionization and emits characteristic radiation

A

Photoelctron 30%

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18
Q

when there is NO change to absorbing atom & photon of scattered radiation is produced

A

Coherent 8%

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19
Q

radiation coming directly out of the target

A

Primary radiation

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20
Q

producespd when primary radiation is filtered & collimated

A

Useful beam

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21
Q

produce from parts other than focal spot

A

Stray

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22
Q

narrows the xray beam & restricts the area of the px face exposure by more than half
made up of lead & tungsten

A

Rectangular Collimator

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23
Q

is the process of removing lower energy photon. made up of aluminum with 1.5 thick

A

filtration

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24
Q

worn prevent stray radiation made up of lead (best metal to stop radiation)

A

Apron

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25
Q

made up of scattered rays

A

Secondary radiation

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26
Q

ways to prevent 2ndary radiation

A

standing 6ft

90-135* from the focal spot

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27
Q

image producespd after exposure to radiation & before processing

A

Latent image

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28
Q

refers to the amount of radiation required to produce a radiographic film of standard density

A

Exposure

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29
Q

diffrence in density appearing on a radiograph

A

Contrast

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30
Q

greatest contrast (short scale)

A

lowest kvp
highest grid ratio
smallest area of collimation

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31
Q

degree of darkening of exposed & processed xrays

A

Density

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32
Q

contrast opaque

hard

A

enamel
dentin
alb
amalgam

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33
Q

contrast
lucent
soft

A

pulp
pdl
sinus
air

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34
Q

least density

A

Direct exposure technique

smallest area of collimation

35
Q

represent thr range of exposure that will produce diagnostically acceptsgle densities on a film

A

Latitude

36
Q

represent the amount of radiation required to produce a radiograph of acceptable densities

A

Speed

37
Q

slow speed film
smaller grain
better definition
more exposure time

A

A, B, C

38
Q

hignspeed film

most commonly used is best way to reduce exposure

A

D E F

Ecta

39
Q

Q. most radioapaque tissue on the oral cavity
most radiolucent tissue on the oral cavity
most radioapaque restorative material
most radiolucent restorative material

A

Enamel
Air
Amalgam & Gold
Methacrylate

40
Q

contains silver halide & silver bromide grains

the side that faces the xray tube intended to br exposed

A

Emulsion

41
Q

made up of polyester polyethylene terephthalate (0.18mm)

support the emulsion by preventing the passage of light

A

Base

42
Q

excessive bending of the film result to
herringbone appearance of the film
phalangioma
penumbra

A

Distortion
Improper position of film
Appearance of thumb
Shadow- distance of focal spot is too far

43
Q

primary cause of injury because they produce free radicals

A

Ionization

44
Q

amount of energy that an ionizing particle transfers to the material traversed permunit distance

A

LET

Linear Energy Transfer

45
Q

with dose threshold requiring at least moderate level of exposure

A

Deterministic effect

46
Q

change resulting from damage to DNA of a single cell

A

Stoachastic effect

47
Q

earliest sign in the oral cavity

A

Mucositis - Candidiasis

48
Q

common w/ more thsn 40 gy dose

A

ORN

49
Q

when there is absence of radiation in the cell divisiom

A

Recovery period

50
Q

Radiosensitive cells

A
  1. Lymphocytes
  2. Bone Marroe
  3. Reproductive cells
  4. Youngnbone
51
Q

radioresistance cell

A

mature bone
muscle cell
nerve cell

52
Q

radiosensitivity of cells depends on

A

Mitotic future
mitotic activty
degree of differentiation

53
Q

critical orgsns on dentsl vicinity

A

Skin
thyroid gland
bone marrow
lens

54
Q

reduce radiatiom of the skin of the pt

A

Aluminum filter

55
Q

skin exposure is low as

A

1-10mR

56
Q

determines the quantity of radiation exposure

A

Dosimetry

57
Q

twin film sensitive to xray beta & gamma rays

A

Film Badge Dosimetry

58
Q

recommended dose for personal monitoring in the dental office

A

300 mR

59
Q

max. wholembody radiation dose

A

50 milliseivetprt per year

60
Q

human lethal dose of radiation

A

600 rads

61
Q

proximal caries. overhang restoratiomn & alveolar bone
advantage
disadvantage

A

Bitewing
absence of cervical burn out
endo , periapical lesion

62
Q

occlusal soze

A

57x76mm

63
Q

paralleling device where the xray beam is perpendicular to the long axis of the tooth
prevent distortion of the imag

A

Paralleing technique (long cone)

64
Q

placed right angle or perpendicular to the long axis of the tooth

A

Bissecting Angle technique

65
Q

detemines the working length of super imposed canls & facio lingual orientation of instruments

A

Slob technique/Cone shift/ Clark shift/buccal object rule

66
Q

they all have intensifying screen to reduce exposure time

A

Extra oral

67
Q

4 layers if intensifying screen

A

Base
Reflective layer
Protective layer
Active layer

68
Q

made up of polyesterr

A

Base

69
Q

made up of titanium oxide (1mm)

A

Reflective layer

70
Q

made up of cellulose (0.7-0.8mm)

A

Protective layer

71
Q

made up of calcium tungstate

A

Active layer (Phosphor)

72
Q

it measure anthropometric landmarks
used to assess skeletal, dental, soft tissue landmarks , planes , angles & distances to classify craniofacial growth
It can evaluate occipital, c1 & c2 fracture

A

Lateral skull projection (cephalometrics)

73
Q

film size of lateral skull projection

A

8x10 inch

74
Q

mainly used for zygomatic fracture

A

Submentovertex / Jug handle

75
Q

mainly of maxillary sinus
one of the best views for coronoid process
can detect hanging drop sign oresent in blow outnfrscture
uses campbell’s & trapnell’s lines for mid face fractures

A

Water’s View ( Occipitomental)

76
Q

show skull vault & frontal sinus

A

PA skull (Caldwell)

77
Q

shows fracture of condyle

A

Reverse town projection (open mouth

78
Q

used to produce an image by reducing the silver bromide & silver halide to solid silver grains

A

Developer

79
Q

below 68*f will result to

A

Deactivation of hydroquinone

80
Q

when there is dramatic change in temp. from one bath to another there will be distortion of emulsion surfsce

A

Reticulation

81
Q

exhausted developer will produce

A

Light radiographs

82
Q

it should have red bulb located 4 ft above worikng area

A

Dardk room

83
Q

used to check safe lighting of darkroom

leakage of light will cause film fog

A

Penny test