part 1 - radiology Flashcards
what is electromagnetic radiation and which is most dangerous to humans
form of energy that can penetrate matter
- gamma rays are most dangerous
what is the preferred wavelength for dental xrays
shorter wavelengths are preferred to dental xrays
what are components of the tubehead and their purpose
metal housing - metal body that contains xray tube
insulating oil - prevents overheating by absorbing xrays
tubehead seal - made of leaded glass and keeps oil in tube
xray tube - where xrays are produced
transformer - alters voltage of electrical current
what are the components of the xray tube and their purpose
cathode
- negative side
- contains tungsten filament in a cup made of molybdenum
- supplies electrons necessary to generate xrays
anode
- positice side
- tungsten target embedded in a large copper rod
- converts electrons into energy and xray photons
what is kv
kilovoltage
- used to control penetrating power of xray beam
- 70-90 kvp is used
- controls quality of xrays
what is mA
milliamperage
- controls number of electrons produced
- controls quantity of xray beams
what is the denisity of an image
density refers to the overall darkness of an image and is controlled by the mA’s
what is the maximal permissible dose for an occupational worker
5 rems a year
what are the types of intraoral and extraoral exposure
bitewings
periapicals
occlusal
cone beam computed tomography
later cephalometric projection
posterior and anterior projection
panoramic imaging
tmj rad
bitewings
shows crown and interproximal areas of max and mand teeth and crestal bone in one image
periapical
shows entire tooth from occlusal surface to beyond the apex and periapical bone
- shows crown and roots of teeth, alveolar bone and apex of root
occlusal
used to examine large areas of upper and lower jaw
cone beam computed tomography
a three dimensional digital imaging method that rotates around a patient
lateral cephalometric projection
used to evaluate facial growth, development, trauma, disease
- shows bone of the face, skull and soft tissue profile
posterior anterior projection
used to evaluate facial growth, development, trauma, disease
- shows frontal and ethmoid sinuses, orbits, nasal cavities
panoramic imaging
allows dentist to view entire dentition in a single imafe
- shows tmj, max sinuses, impacted teeth, jaw pathology, observe eruption patterns
tmj radiography
used to examine bone and relationship of jaw joint
- cannot examine soft tissues
what are landmarks of mandible seen in rad exposures
genial tubercles
lingual foramen
mental ridge
inferior border of mandible
mylohyoid ridge
mental forament
what are landmarks of the maxilla that are seen in rad exposures
incisive foramen
nasal cavity
nasal septum
max sinuses
max tuberosity
coronoid process
what are the principles of paralleling
- image receptor is placed in mouth
- image receptor is positioned parallel to long axis of tooth
- vertical angulation: central ray is directed perpendicular to image receptor
horizontal angulation: central ray is directed through contact areas
principles of bisecting
- film is directly placed against teeth making an angle
- making the film be at an angle not parallel
rad errors
time and temp
- light / underdeveloped
- dark / overdevelopped
- cracked / reticulation of emulsion
chemical
- dark spots / developer spots
- white spots / fixer spots
- yellow colour / old developer
handling
- straight white border / developer cutoff
- straight black border / fixer cutoff
- white or dark areas / overlapped film
- white spots / air bubbles
- black crescent shape / fingernail artifact
- black fingerprint / fingerprint artifact
- black branches / static electricity
- white lines / scratched film
lighting
- black / light leak
- gray / fogged film
advantages and disadvantages of digital
advantages
- immediate viewing
- less radiation
- no chemicals
- no processing errors
disadvantages
- convertion previous records
- learning software
- thickness of sensors
advantages and disadvantages of analogue
advantages
- no need for electricity
- easier to have xrays and not be lost
disadvantages
- takes more time
- takes up more space
what is equipment required for indirect digital imaging
psp plates
image receptor holder
what equipment is required for direct digital imaging
image receptor
sensor
what do restorations appear like on radiographs
radiopaque, white
what are radiolucent structure on radiographs
- foramen
- dentin
- sinuses
- air pockets
- soft tissue
what are radio[aque structures on radiographs
- enamel
- bone
- restoratoins
- metal
- cement
- jewelry
types of images used to detect bone loss
- panoramic
- bitewings
