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Who discovered xrays?
How long ago?
Wilhelm Conrad Roentgen
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List 6 types or examples of electromagnetic radiation.
Cosmic, gamma, xrays, Ultraviiolet, Infrared, visible light, microwaves
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How is electromagnetic energy measured?
Wavelength
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Wavelengthsare measured from ___ to ___, or ___to ___.
Crest to crest
Trough to trough
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Which wavelengths are the most penetrating?
Short wavelengths
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Which wavelengths are the least penetrating?
Long wavelengths
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name the three basic components of an atom.
Electrons, neutrons, protrons
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The process whereby radiation changes the atomic structure of a cell is called what?
Ionization
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List the 4 types of radiation
Primary,secondary, scatter, leakage
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List the 8 body tissues in the order of the most sensitive to the least
Genetic, blood, skin, connectivve tissues, bone, nerve-brain, muscles,glands
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Xrays should be avoid with pregnant women, especially during what period?
1sst trimester
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What are thetwo type of radiation that people are exposed to daily?
Natural and Artificial
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what are the sources of natural radiation?
Sun, atmosphere and Earth (radon)
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Define "Latent Period"
The time between exposure and symptoms
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List the three parts of the xray machine.
Control Panel, Extension arm and Tubehead
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List 3 adjustments found on the control panel
mA, kV and on/off
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Milliamperage (mA) controls the ______ or amount of electrons produced.
Quantity
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What is mA most commonly set at?
10-15
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Kilovoltage (kV) controls the ___ or penetrating power of the beam.
Quality
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What is the purpose of the extension arm?
Position the tubehead towards the pt.
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What part of the xray machine generates the xrays?
tubehead
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The negative side of the tubehead, where the electrons are generated is called the ___.
Cathode -
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When the machine is turned on, what heats up, and produces the electrons?
Filament or coil
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What directs the electrons to the positive side of the tubehead?
Focusing cup
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What is the positive (+) side of the tubehead called?
Anode
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When the button is pushed, the electrons shoot to the ___
Tungsten target
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The area where they (electron) hit is called the ___.
Focal spot
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the xrays are the directed down, through the aperture, or window, and encounter the aluminum ___.
Filter
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What is the purpose of the aluminum filter?
to eliminate soft, weak, xrays
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The primary xray beam continues through the cone, and next encounters what?
Collimator or lead diaphragm
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What is the purpose of the collimator ( lead diaphragm) ?
Reshapes the beam, and limts its size
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the xrays the pass through the open cone, and out the ____.
PID
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The outside of the tubehead is surrounded by what type of casing?
Metal
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the next casing, inside of the metal one is the ---.
Glass casing or Glass envelope
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What is found in between these two casings and why?
Oil bath for cooling
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What is the actual xray film composed of ?
Flexible, thin, polyester plastic
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What is the emulsion composed of?
silver halide crystals, in a gelatin base
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What are halides compounds of?
Chlorine, bromine, and iodine
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What is a " Latent Image" ?
An image stored on an exposed film, that doesn't show until it is processed or developed
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What two things, other than the film, are found inside the packet?
Black paper, and lead foil
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What does the lead foil do?
Absorbs unused xrays
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What are the 5 film sizes, and what are they most commonly used for?
0-pedo (children) 1-narrow anterior 2-adult 3-long bite-wings 4-occlusal
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What is the # 1 cause of cross contamination in a dental office?
Xrays
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List 3 types of intraoral radiographs.
Periapical (PA), bitewings (BW), Occlusal
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What do periapical xrays show?
Entire tooth and surrounding area.
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What portion of the teeth do bitewings show,
and What are they primarly used for?
Coronal portion of max and mand
Detect interproximal decay
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Why are occlusal films taken?
To show large areas of either the max or mand arch
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List 4 processes occlusal films may show.
Cysts, stones, fractures, supernumerary.
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What does FMX stand for?
full mouth xray
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Typically how many films are involved?
18
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What are the two most common extraoral radiographs taken?
Panoramic and cephalometric (ce-fa-lo-metric)
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What are 4 uses of extraoral film,
What do they show?
TMJ, fractures, Impactions
Pathology
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What is the film holder for extraoral film called?
Cassette
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Short scale contrast is mostly ___ and ___.
Black and White
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Long Scale contrast contains multile shapes of ___.
Gray
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Precautions for Operator
Never hold film in patients mouth-if infant or small child, have caretaker hold on lap.
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Operation of the xray head
Activator button turned on (mA)
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Film packet composition
A plastic or polyester film material with an emulsion of gelatin and silver halide/bromide crystals on both sides of the film.
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Developer solution:
Elon is one of the reducers in this solution that causes the crystals to separate.
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Density and Contrast of a film.
Density is the overall darkness of a film
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FYI NOTE
Xrays may be processed in a dark room with a safe light or in a normal room with the use of a " day-light" loader.
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