Radio Flashcards
1
Q
Father of x rays (when)
A
Wilhem Conrad Roentgen (November 8, 1895)
2
Q
Made the first dental radiograph using his own teeth
A
Otto Walkhoff (1896) -25mins naging kalbo
3
Q
First dental radiograph using a skull
A
William J. Morton
William T.G. Morton - inhaled ether as anes
4
Q
First dental radiograph using a live patient
A
Charles Edmund Kells Jr.
5
Q
Designed first dental xray unit
A
William H. Rollins
6
Q
First hot cathode x ray tube
A
William D. Coolidge
7
Q
First paper regarding the dangers associated with radiation
A
William H. Rollins
8
Q
First pre-wrapped dental films
A
Eastman Kodak Company
9
Q
Redefined bisecting technique
A
Howard Riley Raper
10
Q
Introduced long cone paralleling method
A
Gordon Fitzgerald
11
Q
First to discover nitrous oxide as anes
A
Horace Wells
12
Q
Suggested the term anesthesia
A
Oliver wendell holmes
13
Q
Introduced chloroform as anesthetics
A
James Young Simpson
14
Q
First to perform surgery using ether
A
Crawford Long
15
Q
First to isolate cocaine
A
Albert Nieman
16
Q
Ophthalmologist who used topical cocaine as anes in eye surgery
A
Karl Koller
17
Q
First to synthesize Procaine
A
Alfred Einhorn
18
Q
First to synthesize Lidocaine
A
Nils Lofgren
19
Q
Process of converting atoms into ions
A
Ionization
20
Q
Radiation that can overcome the energy required to add or remove electrons of an atom
A
Ionizing radiation (xray and gamma)
21
Q
2 types of ionizing radiation
A
Particulate radiation (tiny particles of matter that possess mass and travel in straight line at high speed)
Electromagnetic radiation (move through space as both particle and wave)
22
Q
Xray velocity
A
Speed of light (300,000 km/s or 186,000 miles/s)
23
Q
Important property of xray in terms of wavelength and frequency
A
Short wavelength = high frequency = more penetrating capabilities
24
Q
Path of travel of xrays
A
Straight line can be deflected/scattered
25
Mass and charge of xrays
No mass, no charge
26
Focusing capability of xrays
Cannot be focused to a point and **always diverge** from a point
27
Absorption property of xrays
Can be absorbed by matter
28
Ionizing capability of xrays
Can cause substances to fluoresce or emit radiation
29
Basic component of a dental x ray machine
Control panel, extension arm, x ray tubehead
30
Protects the xray tube and transformers
Metal housing filled with oil
31
Function of insulating oil
Aids in filtration of xray
Absorbs heat generated during production of xray
32
Aluminum or leaded glass covering of the tubehead that permits the exit of xrays to the tubehead
Tubehead seal acts as a filter to the xray beam
33
Thickness of aluminum disks placed in the path of the xray beam
0.5mm thick
*Filter out non penetrating, longer wavelength xrays*
**Aluminum: filter, lead: deflect**
34
Restricts and reshapes the size of the xray beam
Lead collimator
Has two shapes: rectangular (less excess radiation) >> round (less cone cut)
*Does not filter**
35
Length of position - indicating device (PID)
8 and 16 inches
Aims and shapes the xray beam
36
Leaded-glass vacuum tube that prevents xrays from escaping in all directions but contains a window to permit xray beam to exit
Lead-glass housing
37
Supplies the electrons necessary to generate xrays
Cathode
1. tungsten filament (coiled wire)
2. molybdenum cup (concave reflector focuses into a narrow beam and directs to target of anode)
38
Converts electrons to xray photons
Anode
1. Copper stem (dissipate heat away from tungsten target)
2. Tungsten target (converts e- to xray photons and contains focal spot)
39
Area on the target to which the focusing cup directs the electrons and from which xrays are produced
Focal spot
Smaller FS = sharper radio image
*Placed at an angle
40
Actual size of focal spot
1mm x 3mm
Or
0.6mm - 1.0mm
41
Why tungsten (W)
High melting temp, high atomic number
42
Prevents oxidation or burnout of filament
Vacuum tube
43
Filament circuit volts
3-5 volts
*Regulates the flow of electrical current to the tungsten filament
**Controlled by mA settings**
44
High voltage circuit volts
65,000 to 100,000 volts
*Voltage to accelerate electrons and generate xrays
**Controlled by kilovoltage peak (kvp) settings**
45
Determines quantity of xray produced
Milliamperage
*Also controls the temp of the tungsten filament*
**High mA = increase darkness of film**
46
Determines the quality of xray produced
Kilovoltage
*Controls speed and energy of electrons*
**INC kilovoltage = INC darkness = INC long scale contrast
47
Difference in degree of blackness
Contrast
*High or low (many shades of gray)
48
Range of useful densities on a dental radiograph
Scale of contrast
*Short-scale (2 densities) and long-scale (many densities)
49
Device used to either increase or decrease voltage
Transformers
*Step down - for tungsten filament
*Step up
*Autotransformer - corrects minor fluctuations
50
Process of heating up the tungsten filament to form electron cloud
Thermionic emission
51
Percentage of energy that will become the actual xray vs heat
1% xray
99% heat
52
Dissipates heat
Copper stem, insulating oil
53
Filtration of xray
Leaded glass window of xray tube, Insulating oil, tubehead seal (aluminum), aluminum disk
54
Ideal milliamperage for dental xray machine
7-15 mA
*Quantity and heating of filament
55
Ideal tube voltage for dental xray machine
70kvp
*Quality
*Penetrating ability (together with mA)
56
Thickness of aluminum disk for > 70 kvp and < 70 kvp
0.5mm to 2.0mm
Less than 70 = 1.5mm
More than 70 = 2.5mm
57
Relationship of intensity of beam to the distance from the source
Inverse square law
I1/I2 = (d2)^2 / (d1)^2
58
Thickness of an absorber required to reduce one half the number of xray photons passing through it
Half-value layer
**MEASURES quality of xray beam emitted from the xray tube**
59
Reaction of free radical with other free radicals vs ordinary molecules
Free rad + free rad = no damage
Free rad + ordinary molecule = hydrogen peroxide
60
Occurs when an x-ray ionizes water
Free radical formation = H+ (hydrogen) and OH- (hydroxyl)
61
Theories of radiation injury
Direct damage theory = direct hit nucleus/within the cell
Indirect damage theory = absorbed within cell and forms toxins (H2O2) --> damage cell
62
Biologic effects of radiation
**Stochastic effect**
= sublethal radiation-induced damage to DNA
= No minimum threshold levels
**Deterministic effect**
= Effects when exposure exceeds threshold level
= More exposure, greater chance of cell killing
63
Radiotherapy: stochastic or deterministic
Deterministic
64
Law stating that radiosensitivity is directly proportional to the mitotic activity and inversely proportional to degree of differentiation of cell
Law of Bergonie and Tribondeau
65
Most radioresistant and most radiosensitive biologic tissue
Muscle - resistant (neurons, lens of eyes, mature bone)
Lymphoid organs - sensitive (high: one marrow, epithelium, mucous membrane, gonads, intestines)
66
Effects of radiation to oral cavity
1. Mucositis (increased risk for **candidiasis)
2. Loss of taste acuity
3. Loss of salivary secretion (xerostomia)
4. Anodontia (before calcification of teeth)
5. Malformation/arrested growth (after calcification)
6. Increase viscosity, decreased pH
7. Increase in s. mutans, lactobacillus, candida
67
When can you see Radiation effects? Recovery?
After two weeks effects
After two months recovery
68
Management of radiation caries
Topical 1% NaF
Avoid Dietary sucrose
Resto
Excellent OHI
69
Most serious clinical complication that occurs in bone after irradiation
Osteoradionecrosis -damage to vasculature of periosteum and cortical bone
Vessels: radiosensitive
Bone: radioresistant
70
BRONJ pathophysio
Bisphosphonate affects osteoclast -> no bone resorption -> decrease/occlusion of vasculature
71
In BRONJ, bone is exposed for?
8 weeks
No history of radiotherapy
Px takes/has taken bisphosphonate
72
Personnel protection for radiation safety
Distance: 6ft away from tubehead
Position: 90-135 degree angle to the beam
Shielding
73
Provides proper degree of flexibility of film
Film base (polyester)
74
Serves to attach the emulsion to the base
Adhesive layer
75
Used to suspend and evenly disperse silver halide crystals in film
Emulsion
Serves to absorb the processing solutions and allow the chemical to react with the silver halide
76
2 types of silver halide
Silver bromide (98%)
Silver iodine (2%)
77
Film speed is determined by?
Size of the halide crystals
Bigger crystals - faster film - lesser exposure - lesse image resolution
78
Device that transforms xray energy to visible light to expose the screen films
Intensifying screens
Calcium tungstate - blue light
Rare earth - green light
79
Size of periapical xray
0 - 22x35mm - pedia
1 - 24x40mm - anterior (adult), bitewing (pedia)
2 - 31x41mm - all areas (adult)
80
Size of occlusal film for mx and md jaw
4 - 57x76mm - mx or md jaw
81
Size of bitewing film
0 (22x35mm) - anterior of pedo
1 (24x40mm) - anterior adult, posterior pedia
2 (31x41mm) - posterior of adult
3 (27x54mm) - all posteriors in one side
82
Size of extraoral films
Panoramic (5x12 inches)
Cephalometric (5x7 inches)
83
component of developer that brings out the contrast
hydroquinone - reducing agent
84
component of developer that brings out shades of gray
Elon - reducing agent
85
preservative of developer
sodium sulfite
86
component of developer that softens the emulsion
sodium - carbonate - accelator/activator
87
component of developer that prevents the development of unexposed crystals
potassium bromide - restrainer, anti-fog
88
component of fixer that clears unexposed crystals
sodium/ammonium thiosulfate - fixing agent
89
preservative of fixer
sodium sulfite - prevents deterioration
90
component of fixer that neutralizes basic developer
acetic acid - acidifier
91
component of fixer that shrinks and hardens emulsion
potassium alum
92
Most commonly used sensor for digital radio
Charge-coupled device - silicon baded
Others:
Photostimulable phospor
Flat panel detectors:
Direct flat panel - made up of selenium
Indirect flat panel - made up of cesium iodide or gadolinium oxysulfide
