Final Flashcards
Cathode Components
(-) tungsten wire filament and molybduim cup *generates electrons
Anode Components
(+) tungsten target and copper
General Radiation
when electron hits or comes close to nucleus of tungsten atom
Characteristic Radiation
when an inner shell e- dislodges. Rare, only above 70kVp, causes ionization
Types of Interactions w/ Matter
None (produces image), Photoelectric Effect (x-ray absorbed and collides w inner shell e-,*ionization), Scatter
Compton Scatter
x-ray photon collides w/ outer shell e- and ejects it from it’s orbit. *ionization, common
Coherent Scatter
low-energy x-ray photon interacts w/ out shell electron altering it’s path *NO ionization, less common
Pano Errors
Anterior = skinny; Posterior = fat; Head Turned = further side magnified
Exposure Time Equation
1 impulse = 1/60 second
kV Peak Rule
increase kVp by 15, decrease exposure time by 1/2.
decrease kVp by 15, double exposure time.
Density
(mA) overall darkness of film
Contrast
(kVp) how sharply dark/light areas are separated.
high = few shades of grey (low kVp) | low = many shades of grey (high kVp)
Required Aluminum Filtration by machine
Above 70 kVp = 2.5mm ; Below 70 kvP = 1.5mm
Lead Apron thickness
.25mm by state law
Max Permissible Dose of Radiation
Occupational = 50mSv or 5.0rem / year Not = 1mSv or .1 rem /year
Fixer
hardens emulsion. causes white spots, cutoff = black.
Developer
reduction process. causes black spots, cutoff = white.
Localization Techniques
SLOB or Right Angle (compare PA + cross sectional image)
Film Storage Environment
50-70º, 30-50% humidity
Dark Room Environment
70º (temp too high = fogging) | 50-70% humidity (too high = static electricity)
Ionization
dislodged electrons interact w/ other atoms causing chemical changes - - produced during: photoelectric effect and compton scatter
Free Radical
formed when an x-ray photon breaks up (ionizes) water causing unstable, uncharged atoms. *primary cause for cell damage
Stochastic Effects
increasing dose = increasing occurrence of effects. no threshold. ie. cancer, genetic mutations
Non Stochastic Effects
large doses cause effects. has threshold. ie. hair loss, erythema, fertility
Types of Caries
Incipient (-1/2 thru enamel), Moderate (+1/2 enamel), Advanced (-1/2 dentin), Severe (1/2+ dentin), Root Surface (below CEJ)
Resembles Caries
Cervical Burnout, Mach Band (overlapping), Non-metallic Restorations (composite, acrylic), Attrition/Abrasion
Perio Disease Stages
1 = <15% coronal root 3rd , 2 = 15-33% , 3 = middle root +
Perio Disease Calculation
CEJ to Apex / CEJ to Bone Crest = x / age
Slow = < .23 , Mod = .25-1.0 , Rapid = 1.0 +
Pericoronal
pathology noted at crown of impacted tooth
Unilocular , corticated
single, roundish, w/ radiopaque border
Radiolucent Pathologies
Pulpal Sclerosis/Obliteration, Periapical Granuloma/Abscess
Radiopaque Pathologies
Condensing Osteitis, Sclerotic Bone, Hypercementosis, Mandibular Tori
Density has a DIRECT relationship with
mA, kVp, time - high density = darker image
Contrast + kVp
INVERSE relationship
