ANSWERS SCORED A+
✔✔Density - ✔✔Film blackening (the amount of light transmitted through a film)
✔✔Contrast - ✔✔The visual differences between shades ranging from black to white in
adjacent areas of the radiographic film
✔✔Detail - ✔✔The sharpness and clarity of the outline of the structure on the image
shown on the film
✔✔PID - ✔✔Any device attached to the tube head to direct the useful beam of
radiation.
✔✔Filters - ✔✔Absorbing material, usually aluminum, placed in the path of the beam of
radiation to remove radiation (soft) x-rays
✔✔Collimator - ✔✔A diaphragm, usually lead, designed to restrict the dimensions of the
useful beam; looks like a lead washer
✔✔mA - ✔✔Determines the number of electrons available at the filament
✔✔kVp - ✔✔the voltage force that causes electrons to move; the higher the voltage, the
stronger the resulting x-ray
✔✔What makes x-radiation dangerous? - ✔✔Its ability to cause ionization, resulting in
possible acute and chronic effects
✔✔What are ions and what is their relationship to dental radiography? - ✔✔Ions are
charged particles; x-rays can break apart atomic structure and create ions.
Ions can recombine in combinations that are harmful to the body.
✔✔Exposure
Absorbed dose
Dose equivalent - ✔✔Air-Roentgen-Coulombs/kg
Amount of energy deposited in matter-Rad-Gray
Amount of energy deposited in living tissue-Rem-Sievert
✔✔When would a patient's whole body be exposed to radiation? - ✔✔When outdoors in
the sun, or during a nuclear accident or nuclear war
✔✔List the following body cells in order of their tissue sensitivity, with the most resistant
cells listed first: - ✔✔Muscle-Nerve and brain-Bone-Connective tissue-Skin-Immature
reproductive cells-Blood cells
, ✔✔Identify and order the four stages of exposure. - ✔✔Exposure, latent period, period
of injury, period of recovery
✔✔What is meant by latent period? - ✔✔Time between exposure and visible effects.
✔✔If damaged, how long does it take genetic cells to repair? - ✔✔Genetic cells do not
repair
✔✔Should a dental assistant be more concerned with acute exposure or chronic
exposures? - ✔✔Chronic exposures
✔✔What are the two best ways to limit the amount of radiation exposure to a patient? -
✔✔Make exposures only when there is a diagnostic need
Use the fastest film possible
✔✔What is the function of a filter? - ✔✔Remove longer wavelength or soft x-rays from
the primary beam
✔✔What is the function of the collimator? - ✔✔Reduce the size of the primary beam
and thereby the amount of tissue exposed to radiation
✔✔Why are film holders considered a way to reduce radiation exposure? - ✔✔Fewer
retakes are needed if film holders are used
✔✔What is an artifact? - ✔✔A blemish or image on the radiograph that is not present in
the actual object
✔✔What are effects of chronic exposure to radiation? - ✔✔Shortened life span, cataract
formation, embryologic defects, genetic mutations, cancer
✔✔What are effects of acute exposure to radiation? - ✔✔Erythema, vomiting, diarrhea,
hair loss, nausea, hemorrhage
✔✔What should be included in a written quality assurance program? - ✔✔Monitoring
and maintenance schedule, log of tests and results, log of retakes, staff responsible for
tests, periodic evaluation of plan
✔✔What is the purpose of an output test? - ✔✔Check the function of the x-ray unit
✔✔Why are quality control tests performed? - ✔✔To discover problems before
exposures are made on patients, to maintain a high standard of image quality, to keep
patient exposures to a minimum and reduce the number of retakes