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69 Cards in this Set
- Front
- Back
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what type of xray machine use a continually decreasing mA for the shortest time possible? |
falling load generator |
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what new kVp is needed to double density if the original kVp is 100 |
115 |
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to what height must in-wall secondary protective barriers extend? |
the ceiling |
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the primary type of grid used in diagnostic imaging is what |
focused |
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the unit of activity in the traditional system of measure is the? |
curie |
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this device is placed in the circuit between the autotransformer and the high-voltage transformer |
prereading voltmeter |
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mA linearity must be recalibrated when a difference of: |
10% is noted throughout the mA range of equipment being tested |
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some xray tubes use the focusing cup as an electronic grid that can turn the current on and off rapidly, allowing for very short and precise exposure times such as those needed for rapid serial exposures. these tubes are referred to as what |
grid-controlled tubes |
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cleaved or broken chromosomes are a consequence of ionizing radiation striking and breaking ___? |
two opposite areas of sugar-phosphate molecular chain of DNA macro molecule that lie within the same rung |
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this may occur if contrast material extrvasates at the site of injection |
local irritation |
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how is damage to the cell being irradiated described? |
somatic effects |
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personnel monitoring is required when there is a chance that a radiographer will be exposed to: |
1/4th or more of the annual absorbed dose equivalent limit of 5 rem in any 1 year |
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one of the functions of the vacuum created by the glass envelope surrounding hte working components of the xray tube is what? |
allow free flow of electrons from cathode to anode |
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what occurs when radiation transfers its energy to the DNA to RNA |
direct effect |
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as mAs is increased, density: |
increases in the same amount |
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is kilovoltage applied when the first stage of a two-stage exposure switch is depressed? |
NO |
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the measure of a grid's ability to enhance contrast is called what? |
contrast improvement factor |
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a positive contrast agent administered to the patient when barium sulfate is contraindicated is what? |
aqueous iodine compound |
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as kVp is decreased, the wavelength |
increases |
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barium sulfate is what called an "____ salt" |
inert |
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how a reasonable person with similar education and experience would perform under similar circumstances defines what? |
reasonably prudent person doctrine |
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the minimum source to skin distance for portable fluoroscopes is at least |
15 inches |
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the fluoroscopic image is brightened and reduced in size by means of the |
image intensifier |
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mAs controls the number of electrons passing from ___? |
cathode to anode |
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can a pulse be found behind the knee? |
YES |
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humans are partially protected from cosmic rays by? |
earths atmosphere |
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the purpose for establishing annual limits for occupationally exposed individuals is to |
control the maximum risk to a person in any year |
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movement of electrons in a conductor produces a magnetic field around the conductor; a coiled conductor through which an electric current is flowing, will have overlapping magnetic fields |
electromagnetism |
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radiation doses up to what level are considered lower risk to the embryo-fetus |
15 to 20 rads |
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most damage from exposure to radiation occurs as a result of what? |
indirect effect |
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the relationship between kVp and density is |
direct, although not proportional |
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the prefix "a-" means |
without |
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for low-ratio grids the radius is |
wide |
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near the pyloric portion of the stomach, the notch located along the lesser curvurature is the |
incisura angularis |
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a spinning-top test is normally use to evaluate the performance of what |
single-phase equipment |
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rotation of the target allows for: |
greater heat dissipation |
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the most common result of LET and direct effect is what? |
nothing (there is no effect) |
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how is the workload factor measured |
mA minutes per week |
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how does the energy of a scattered photon compare with that of the incident photon? |
less energy |
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what must precede any exam involving iodinated contrast |
thyroid assessment |
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what is the most frequent cellular response to ionizing radiation |
nothing (the most common result of linear energy transfer (LET) is no effect) |
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the unit of measurement involves counting positive and negative particles created when radiation passes through air |
roentgen |
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what surrounds a current running through a conductor |
magnetic field |
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the OSL dosimeter may be scanned and reanalyzed how many of times |
an unlimited number of times |
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an absorbed dose of ionizing radiation is stated in rad. to conver this dose into gray, an SI unit, the radiographer must: |
divide the dose stated in rad by 100 |
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what transformer is used in the high-voltage section of the xray circuit? |
step-up transformer |
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an interaction that produces xrays at the anode as a result of outer shell electrons filling holes in the K shell is called what interaction |
characteristic |
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exposures must be within this amount of one another of _____ when a quality control test is performed to ensure that the same exposure factors produce consistent x ray output |
5% |
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quality control test of the penetrating x ray beam, the result of the test must be within _____ kVp. |
4 kVp |
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the accuracy of collimation at a 60 inch SID must be: |
plus or minus 1.2 inches |
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beam quality is expressed using what unit of measurement |
half-value layer |
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the charge on the atomic nucleus |
positive |
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the waves of electromagnetic radiation are called what |
sine waves |
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radiation is more intense on what side of the xray tube |
cathode |
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the movement of electrons between objects is called |
electrification |
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opposing voltage created in a conductor by passing alternating current through it describes what? |
self-induction |
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this changes electric voltage and current into higher and lower values and operates on the principle of mutual induction, so it requires alternating current. what is this called |
transformer |
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this type of timer is controlled by a microprocessor |
electronic |
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n-type and p-type semiconductors are silicon based and are located where |
recitifier |
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what two things are both placed between the auto transformer and the high-voltage transformer |
timer, prereading voltmeter |
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full wave rectification produces |
pulsating direct current |
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when going form single-phase to three-phase or high frequency machines, kVp values _____ |
decrease 12 to 16% |
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the rotation of the target is stopped by a braking action provided by the what |
induction motor that spins the anode |
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the larger the actual focal spot, the _______ the heat capacity |
greater |
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the increase in brightness caused by acceleration of the electrons in the image intensifier is called what |
flux gain |
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whne performing radiographos on a patient with a larger plaster cast, an increase of mAs by ____% or ___-____kVp is necessary. |
100%, 8-10 kVp |
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determination of film sensitivity and identification of automatic processing problems can be evaluated by using what cure type? |
sinsitometric |
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when performing retrograde cystogrpahy, which projection will show the anterior and posterior walls of the bladder? |
lateral projection |
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what is the name of the fracture that is associated with the proximal fibula by injury to the medial side of the ankle and disruption of the distal tibiofibular syndesmosis |
maisonneuve fracture |
