Term
|
Definition
positive portion of xray tube
contains kVp
(this is the side of the tubehead with step up transformer and the tungsten target) |
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Term
|
Definition
negative portion of the x-ray tubehead it fires electrons to the anode
contains MA control
tungsten filament wire and molybdenum for focusing
MA control regulates the step down transformer
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Term
| what is the purpose collimation? |
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Definition
reduces the DIAMETER of the primary beam
restricts the size and shape. |
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Term
| explain the electron cloud |
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Definition
| thermionic emission (heat) with electron cloud |
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Term
| how does E film compare with D film? |
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Definition
| E speed film needs 1/2 exposure time needed for D film |
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Term
| how does F speed film compare with D film? |
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Definition
| F speed film takes 60% less exposure time than D film |
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Term
| what does exposure time determine? |
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Definition
| exposure time determines the # of xrays produced |
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Term
| what is the purpose of the filament? |
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Definition
| releasing electrons is what a filament is for |
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Term
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Definition
it is the target area of the anode
directs the x-rays
the smaller the size, the better the sharpness |
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Term
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Definition
| the gray is a unit of measurement 1Gy=100 rads or 1 j/kg |
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Term
| what is the purpose of the holding device? |
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Definition
| to stabilize the film: XCP use |
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Term
| impulse is how many per second in radiography |
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Definition
| impulses are 60 impulses/second |
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Term
| what is the purpose of intensity screens |
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Definition
| intensity screens reduce exposure time |
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Term
| the separation of electrons from molecules to change chemical activity is called? |
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Definition
|
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Term
|
Definition
| inonizing radiation uses electromagnetic radiation (xrays and gamma rays) |
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Term
|
Definition
units of absorbed dose
1 rad=0.01j/kg |
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Term
| this is responsible for quality of radiographs and the penetration and is controlled in the anode |
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Definition
| kilovolage/kvp Quality and penentration and happens in anode |
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Term
| what is the range of kVp used for most dental radiography? |
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Definition
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Term
| this is known as the time between exposure and development of biologic effect. |
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Definition
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Term
this is used to limit the size and shape
the lead thickness is 1/8 inch
the size is 2 and 3/4 inches or 2.75 inches
if the shape is rectangular it will be 1-2 inches at the skin |
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Definition
| lead diaphram limits size: know all measurments for boards |
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Term
LD 50/30 dose
board favorite question*** |
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Definition
| the dose of radiation tht is lethal for 50% of people in 30 days. |
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Term
Maximum accumulated dose
board favorite question*** |
|
Definition
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|
Term
what are the maximum permissable doses for occupational, general public, patient
pregnant operator
popular board Q*** |
|
Definition
MDR's
patient-6.2 MSV
occupational- 5 rem/year (50mSv=5000 millirems=5rem)
general public- .5 rem/year
pregnant operator- .5 rem/year |
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Term
|
Definition
| persons who work with radiation should attempt to keep all radiation as low as reasonably possible. |
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Term
| radiosensitive cells (high sensitivity) |
|
Definition
-small lymphocyte
-bone marrow
-reproductive cells
-intenstinal mucosa
-skin
-lens of eye
-oral mucosa |
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Term
| radioresistent cells (low sensitivity) |
|
Definition
-muscle tissue
-nerve tissue
-mature bone and cartilage
-salivary gland
-thyroid gland
-kidney
-liver |
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Term
|
Definition
| occlusal plane of premolars and 1st molars |
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Term
|
Definition
divides left and right sides of the body
aka sagittal plane |
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Term
| this affects the quantity or # of x-rays and density |
|
Definition
| milliamperage (range is 7-15 ma for dental radiography) |
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|
Term
| coronal or frontal plane describes? |
|
Definition
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|
Term
| transverse plane divides? |
|
Definition
| transverse is top from bottom |
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Term
|
Definition
| mean curvature from incisal edges of centrals to tips of occluding surfaces of wisdom teeth |
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Term
|
Definition
the cone that is lead lined and open ended which prevents secondary radiation
directs the direction of the central axis of the x-ray beam
establishes source surface and source film distance |
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Term
| aluminum filter characteristics |
|
Definition
absorbs long wave lenghts at :
70kvp or higher
low energy and secondary waves
2.5 (2 3/4 inches) of aluminum
reduces the amount of soft radiation reaching patients face
(takes out longer wavelenght) |
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|
Term
| object film distance is the distance between ____________ and ______________ |
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Definition
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|
Term
| object film distance increases with what technique? |
|
Definition
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Term
|
Definition
Absorbed dose in tissue
100rad=1Gy |
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|
Term
| this is the amount of energy absorbed per unit mass of tissue at the site of interest |
|
Definition
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|
Term
| R- is a roentgen it refers to |
|
Definition
| r= exposure rate and output of machine |
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Term
| what type of bulb is in a safe light |
|
Definition
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|
Term
| safe light should be ____ feet above working surface |
|
Definition
| 4 feet above working surface |
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Term
| when would an orange filter be used for safelight? |
|
Definition
intraoral ( endo case study is common)
remember eat and orange so it goes inside. |
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Term
| what is secondary radiation? |
|
Definition
| long wavelengths with scatter radiation |
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|
Term
| how much lead is in a lead apron |
|
Definition
| 0.25-0.30 mm of lead in apron |
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Term
| this is a unit of biologic equivalence |
|
Definition
seivert
Sv (1 Sv= 100 rem) |
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|
Term
| which is better, long PID or short PID |
|
Definition
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|
Term
|
Definition
| injury that occurs in a person recieving radiation |
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|
Term
| what cleans fixer solution stain from nylon |
|
Definition
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|
Term
|
Definition
distance from source to PID in housing, lenght of PID
intensity varies inversely, increased distance preserves definition and quality |
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Term
|
Definition
| includes primary radiation and back scatter from irradiated underlying tissue |
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Term
|
Definition
| minimum dose that will produce a detectable degree of any given effect |
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Term
|
Definition
|
|
Term
| units of radioactivity are |
|
Definition
curie (Ci)
Becquerel (Bg) |
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|
Term
| the distance of operator from pid during radiologic procedure should be |
|
Definition
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|
Term
|
Definition
|
|
Term
| blurred image can be caused by |
|
Definition
movement of pt
movement of film
movement of arm on xray unit |
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|
Term
true or false
cone cut will only show on one side of the film
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|
Definition
| true cone cut only appears on one side of the film |
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Term
|
Definition
| images overlap (the same film was used 2x) |
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|
Term
| elongation: what is the fix |
|
Definition
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|
Term
|
Definition
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|
Term
| when film is placed backwards this occurs |
|
Definition
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|
Term
| if film was too light what happened? |
|
Definition
| film too light= not enough Kvp |
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Term
|
Definition
| occurs from incorrect horizontal angulation |
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|
Term
| fixer spots show up like __________ spots. |
|
Definition
| fixer = white spots, they turn to yellow after time has passed and affect the archival integrity of the film |
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|
Term
| dark spots on the film occur from _____ splash. |
|
Definition
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|
Term
| if film was exposed to light it will develope what color |
|
Definition
| film exposed to light= black film |
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|
Term
| if film is discolored what happened in processor? |
|
Definition
| discolored film = insufficient fixer time |
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Term
|
Definition
| not submerged in developer completeley (the bromide washed off because not exposed to fixer first) |
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|
Term
|
Definition
light in darkroom
scatter radiation (secondary)
improper safelight
underdevelopment |
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|
Term
| when a film is overdeveloped it could have? |
|
Definition
dark film,
film fog,
solution too hot
left in developer too long |
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|
Term
| if solution is too cold the film will show up? |
|
Definition
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|
Term
| if film goes from hot to cold too quickly what shows on film |
|
Definition
| reticulation lines, they look like bubbles |
|
|
Term
the thickness of the lead shield is?
a. .75 mm
b. .25mm
c. 2.75 mm
d. 1.5 mm |
|
Definition
|
|
Term
the solution most temperature sensitive in the processing solution is?
a. sodium sulfite
b. sodium carbonate
c. elon hydroquinone
d. none of the above |
|
Definition
|
|
Term
alveolar bone crest resorption is best detected in the?
a. panorex
b. occlusal film
c. periapical film
d. bite wing film |
|
Definition
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|
Term
film exposed to light while being developed will be?
a. light
b. dark
c. blurred
d. reticulated |
|
Definition
|
|
Term
in film processing, the developing solution acts on?
a. the entire emulsion
b. those areas that will appear as radiopacities
c. that part altered by the xrays
d. none of the above |
|
Definition
| c. that part altered by the xrays |
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|
Term
for intraoral radiography, the diameter of the useful beam at the end of the cone should not exceed ?
a. 1.5 inches
b. 2.75 inches
c. 3.25 inches
d. 4.0 inches |
|
Definition
|
|
Term
which of the following kVp settings will produce the greatest contrast among images on a radiograph?
a. 65 kVp
b. 75 kVp
c. 80 kVp
d. 90 kVp |
|
Definition
| a. 65 kVp will produce the greatest contrast |
|
|
Term
the purpose of the molybdenum cup us to?
a. focus the electrons toward the anode
b. focus electrons toward cathode
c. protect aluminum filter
d. increase the incoming voltage |
|
Definition
| a. focus electrons toward anode |
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|
Term
what matter is irradiated by xrays, which of the following phenomena is produced?
a. heat
b. leakage radiation
c. secondary radiation
d. diverging radiation |
|
Definition
|
|
Term
in x-radiation, ionization has occurred when?
a. cell death takes place
b. an electron is displaced from the orbit of an atom
c. photons penetrate matter
d. all of the above |
|
Definition
| b. electron is displaced from orbit of atom |
|
|
Term
an early clinical sign of excessive exposure to radiation is ?
a. jaundice
b. bleeding
c. hair loss
d. erythema |
|
Definition
| d. erythema is a clinical sign of excessive radiation |
|
|
Term
penumbra has to do with?
a. cone cut
b. overlap
c. detail
d. reticulation |
|
Definition
| penumbra has to do with detail |
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|
Term
film holding devices are suggested when taking intraoral radiographs in order to?
a. reduce radiation to patient
b. decrease image distortion
c. stabilize film
d. increase image contrast |
|
Definition
|
|
Term
relative sensitivities of cells and tissues to radiation depend upon all of the following except:
a. age
b. dose rate
c. type of radiation
d. specific areas involved
e. blood type |
|
Definition
|
|
Term
| the most sensitive cells and tissues to ionizing radiation are blood forming cells and reproductive cells. The least sensitive are adult bone and nerve. |
|
Definition
|
|
Term
the speed of the film is determined by the :
a. grain
b. date of the film
c. operator speed
d. none of the above |
|
Definition
|
|
Term
if the grain size is small, then the film speed is?
a. faster
b. slower
c. no difference |
|
Definition
| if grain is small, film speed is fast |
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|
Term
for posterior exposure, the clinician should stand behind the patient's head at a _________ degree angle to the central beam, and at least _______ feet or inches away?
a. 90-135 degrees, 6 feet (2 meters)
b. 45-135 degrees, 6 feet (2 meters)
c. 90-135 degrees, 6 inches (2 meters)
d. 45-135 degrees, 6 inches (2 meters) |
|
Definition
| a. 90-135 degrees and 6 feet away |
|
|
Term
if the focal/ film distance is increased from 8" to 16", the exposure needs to be:
a. halved
b. decrease
c. quadrupled
d. increased by 1/4th |
|
Definition
c. quadrupled
if film was at 8, and distance is greater to 16, exposure would be multiplied by 4 |
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