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90 terms

Radiology Final

STUDY
PLAY
Amperage
The measurement of the number of electrons moving through a conductor. Measured in amperes (A) or milliamperes (mA)
Voltage
The measurement of electrical force that causes electrons to move from a negative pole to a positive one. Measured in volts (V) or kilovolts (kV)
Milliamperage adjustment
Can increase or decrease the number of electrons passing through the cathode filament
Kilovoltage peak adjustment
Can control the current passing from the cathode to the anode.
Step-Down Transformer
Used to decrease voltage from the incoming 110- or 220-line voltage to the 3 to 5 volts used by the filament circuit.
Step-Up Transformer
Used to increase incoming voltage to 65,000 to 100,000 volts used by the high-voltage circuit.
General Radiation
Produced when an electron hits the nucleus of a tungsten atom or passes very close to the nucleus of a tungsten atom.
Characteristic Radiation
Produced when a high-speed electron dislodges an inner-shell electron from a tungsten atom and causes ionization of that atom. Occurs only at 70 kVp and above.
Primary Radiation
The penetrating x-ray beam that is produced at the target of the anode
Secondary Radiation
X-radiation created when the primary beam interacts with a matter
Scatter Radiation
A form of secondary radiation, the result of x-rays that has been deflected from its path by an interaction with matter.
Compton Scatter
The x-ray photon is deflected from its path during its passage through matter
Coherent Scatter
An x-ray photon that has its path altered by matter.
Density
Darkness or blackness on film. If kVp is increased film will be darker. If decreased, film will be lighter
Contrast
Sharper of dark and light areas and how they are separated on film. Low kVp results in high contrast (many white and black areas, very little gray). Useful when diagnosing decay. High kVp results in low contrast (many shades of grade) Useful for periodontal disease screening/periapical disease
Free Radical Formation
Cell damage occurs through formation of "free radicals". Free radicals are formed when an x-ray photon ionizes water.
Direct Injury
Occurs very little; most photons pass through cell with little or no damage
Indirect injury
Occurs frequently due to the high concentration of water in cells.
Nonthreshold dose-response curve
Suggest that no matter how small the amount of radiation received, some biologic damage occurs.
Stochastic effects
A direct function of the dose. No dose threshold; effects do not depend on the magnitude of the absorbed dose (Examples: cancer and genetic mutations)
Nonstochastic (deterministic) effects
Somatic effects that have a threshold; effects increase in severity with increasing absorbed dose. (Examples: Erythema, loss of hair, cataracts, and decreased fertility)
Latent Period
Time between exposure to ionizing radiation and the appearance of observable clinical signs.
Total dose
Quantity of radiation received or total amount absorbed (more damage with tissue absorbing large quantities of radiation)
Dose Rate
Rate which exposure to radiation occurs and absorption occurs (more damage occurs with high dose due to rapid delivery and does not allow for repair)
Amount of tissue irradiated
Area of body exposed total body produced more adverse effects
Cell sensitivity
More damage can occur in younger or rapidly dividing cells
Short-term effects
Do not occur in dentistry
Long-term effects
Effects seen years, decades, or generations later
Somatic cells
All cells except reproductive; effects are seen in person irradiated
Genetic cells
Reproductive (ova, sperm). Effects are passed on to generations. Genetic damage cannot be repaired
Radiosensitive cells
Small lymphocyte, bone marrow, reproductive cells, immature bone
Radioresistant cells
Mature bone, muscle, nerve
Roentgen
Coulombs per kilogram
Rad (Radiation absorbed dose)
Gray
Rem (Roentgen equivalent (in) man)
Sievart
Inherent filtration
Primary beam passes through glass window, insulating oil, tubehead seal. 0.5 to 1.0 mm of aluminum
Added filtration
Aluminum disks between collimator and tubehead seal. Aluminum disks filter long wavelength, low energy x-rays from x-ray beam. 0.5 mm increments
Total (inherent + added) filtration
Dental x-ray machines operating 70 kVp or below: minimum 1.5 mm aluminum filtration
Dental x-ray machines operating above 70 kVp: minimum of 2.5 mm. of aluminum filtration.
Collimation
Restricts size and shape of beam to lower patient exposure
Round: cone shaped beam-2.75 inches in diameter
Rectangular: Rectangular beam slightly larger than size 2 film- lowers patient exposure
Conical PID
Closed, pointed cone-high production of scatter, not used any longer.
Rectangular and round PID
8 inch and 16 inch; longer are preferred due to less divergence of beam, open ended and lead lined.
Cortical Bone
"Cortex"-> dense, outer layer; also called compact bone-appears radiopaque on film
Cancellous
"Arranged like a lattice"->soft, spongy bone located between 2 layers of cortical bone; spaces are trabeculae that are filled with bone marrow.
Process
Marked prominence that appears radiopaque.
Ridge
Linear prominence that appears radiopaque.
Spine
Sharp, thornlike projection that appears radiopaque.
Tubercle
Bump or nodule that appears radiopaque
Tuberosity
Rounded prominence that appears radiopaque
Canal
Tube that passes through bone, contains nerve canals/blood vessels/and appears radiolucent
Foramen
Opening/hole in bone that allows the passage of blood vessels/nerves and appears radiolucent
Fossa
Scooped out of depressed area of bone that appears radiolucent
Sinus
Hollow space, cavity that appears radiolucent
Septum
Bony wall that divides 2 spaces, radiopaque
Suture
A line of union between adjoining bones, found only in skull; appears as radiolucent line
Incisive (Nasopalatine) Foramen
Located at the midline of anterior portion of hard palate behind maxillary central incisors; round radiolucency between roots of centrals
Superior Foramina of incisive canal
Two small openings (radiolucent) found on floor of nasal cavity->common exit is incisive foramen
Median palatine suture
Extends from alveolar bone between maxillary centrals to posterior hard palate; seen as a radiolucent line
Lateral Fossa
Between canine and lateral incisor, depression is not always visible, radiolucent
Nasal Cavity/Fossa
Pear shaped compartment, appears above maxillary incisors. Appears as a large radiolucent area above the maxilla.
Floor of Nasal Cavity
Cortical bone, radiopaque band above maxillary incisors
Anterior Nasal Spine
V-shaped radiopacity at intersection of floor of nasal cavity and septum
Inferior Nasal Conchae
Thin, curved areas of bone, radiopacities within nasal cavity and septum
Maxillary sinus
Located above maxillary premolar/molar teeth, border is made up of cortical bone; sinus cavity is radiolucent compartment
Septa within maxillary sinus
Within maxillary sinus; acts as a division, radiopaque lines sometimes not visible
Nutrient Canals
Tubes within maxillary sinus that carry nerves, blood supply, radiolucent band with boundary of two radiopaque cortical bony lines
Inverted Y
Intersection of maxillary sinus and nasal cavity, radiopaque, cortical bone; above maxillary canine.
Maxillary Tuberosity
bony prominence posterior to maxillary third molar; radiopaque
Hamulus
"hooklike", posterior to maxillary tuberosity; extension of medial pterygoid plate of sphenoid bone; radiopaque
Zygomatic process of maxilla
cortical bone; J or U shaped radiopacity
Zygoma
"Cheekbone"; cortical bone; radiopaque band extending from zygomatic process.
Ramus
Posterior to mandibular third molar
Body of Mandible
U-shaped portion extending from ramus to ramus
Alveolar Process
encases/supports teeth
Genial Tubercles
Bump of bone, muscle attachment; lingual aspect of mandible, "ring shaped" radiopacitiy below mandibular incisors.
Lingual Foramen
Surrounded by genial tubercle, hole in bone near mandibular midline, radiolucent
Nutrient Canals
Mostly seen in mandibular nerve/blood supply vertical radiolucent lines
Mental Foramen
Hole in bone below mandibular premolars, blood supply to lower lip exits here; radiolucent; often misdiagnosed for periapical pathology
Mylohyoid Ridge
Internal ridge of mandible muscle attachment, continuous with internal oblique ridge; radiopaque line
Mandibular Canal
tube that travels length of mandible, radiolucent; has cortical walls, houses inferior alveolar nerve
Internal Oblique Ridge
Continues from ramus; radiopaque band
External Oblique Ridge
superior to internal oblique ridge; anterior border of ramus ends in external oblique ridge; radiopaque band
Submandibular Fossa
depression of bone; submandibular salivary gland found here; radiolucent; below mylohyoid ridge
Coronoid Process
anterior ramus of mandible; attachment for muscle of mastication; superimposed around maxillary tuberosity.
Lamina Dura
Surrounds root, cortical bone, radiopaque
Alveolar Crest
coronal part of alveolar bone, between teeth, cortical bone, radiopaque
Periodontal Ligament Space
Space between root and the lamina dura, thin, radiolucent line, healthy PDL is uniform thickness
Developer Solution
Reduces exposed silver halide crystals into black metallic silver a makes dark/black areas on film; unexposed silver halide crystals are unaffected by developer
Fixer Solution
Removes unexposed silver halide crystals and creates white/clear areas on film; black metallic silver remains on film.
What is the optimum temperature for manual processing?
68 Degrees F
What are the conditions required for the darkroom
16-20 square feet (at least 4x4)
Light tight
Safelight must be at least 4 feet from the working area