UNIT II & III X-ray REVIEW
what films are extra-oral films
Panorex, Cepholometric, Orthopantomograph
importance of operator standing behind lead shield when exposing x-rays is to prevent being exposed to
Secondary, Direct, Scatter, and Leakage radiation
at what age is the 1st radiographic survey on child
age 3
what happens when you sterilize
all forms of microorganisms have been destroyed
what prevents weak radiation leaving tube during exposure
aluminum filter
procedure regarding immersion disinfection
any instruments added to solution before disinfection time is up you must start timing all over
what is ION
atom that has lost an electron
why is radiation considered harmful
because it is cumulative
what x-rays show interproximal and are cavity detecting radiographs
bite wing x-rays (BWX)
material responsible for giving support & stiffness to x-ray film
cellulose acetate
an extra-oral film that shows a lateral view of the skull is
cephalometric
distortion
changes in shape or size of object
what is reticulation
cracking of film emulsion due to excessive heat during processing
when using ultra speed film would you increase or decrease exposure time
decrease
Radiolucent
degree of darkness on a film
what is the negatively charged particle that is responsible for producing dental radiographs
electrons
what stops the developing agents
fixer
what causes films to turn brown and discolor after a few days
improper washing
where is the thermometer placed
in the water tank
what causes overlapping
incorrect horizontal angulation
four body tissues most sensitive to radiation
intestinal tissue, embryo, cornea of the eye, bone marrow
speed of electrons through a circuit is referred to as
kilovoltage (KV)
radiation protection for pt.
lead apron (NOT LEAD SHIELD)
how is collimation accomplished
lead washer
what is a good anatomic landmark to look for when mounting an upper bicuspid film
maxillary sinus
Instrument from XCP kit that allows operator to align PID at the right angle to the film and long axis of the tooth is the
metal indicator rod
cathode
negative terminal
why dental mask is worn
protect mucous membrane of nose & mouth
the value of radiographs for Pt. education includes
results in missing teeth, implants/ bridges from restored mouths, results in reconstructive surgery, orthodontic conditions
what is radiopaque
shows white on then film
substance found in emulsion of film that is responsible for an x-ray
silver halide crystals
what causes cone cutting
the center of the primary beam was not directed to the center of the film
what part of the x-ray machine produces radiation
the tube
what is density
thickness of an object being radiated
what is the purpose of the lead foil of a film packet
to prevent secondary radiation from fogging film
what causes foreshortening
too high a vertical angle
besides gamma rays, what additional radiation wave from the EMR spectrum is considered harmful to tissue due to its wavelength
ultraviolet
know why ultrasonic cleaner is preferred to hand scrubbing
uses sound waves to reach all areas of the instruments, uses cavitation process, safer for the auxiliary
what is considered radiation protection for operator during Pt. exposure
6-8ft distance from tube, lead shield, double walled gypsum board
how much radiation reduced by using Ultra Speed film
85%
contrast
Diff. betw. black, white, & shades of gray
hat is occupational dose limits for radiation exposure in a calendar quarter (13 wks.) for the whole body
1.25 REMS
what is the target distance for the paralleling technique
12-16 inches
full mouth x-ray for an edentulous Pt. would include
14 PA's no BWX
exposure to edentulous Pt. can be reduce by
25%
minimum allowable distance of the dark room safety light from the working counter top
4ft.
who can legally expose x-rays described by "California Law"
DA who passes board approved course and receives x-ray certificate. at least 18yrs of age
