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37 Cards in this Set
- Front
- Back
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What are the 3 principle parts of an x-ray system
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operating console, high voltage generator, x-ray tube
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what is the kinetic energy equation
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KE =1/2 mV(2)
KE in joules V meters per second mass in kilograms |
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Kinetic energy equation states
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objects in motion have kinetic energy proportional to their mass & to the square of their velocity
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what is more important when determing the magnitude of KE Velocity or Mass
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velocity
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if all electrons have the same mass what is increased when kVp is raised
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electron KE is increased
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as electron KE increased what elese is increased
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intensity (quantity)
energy (quality) of the x-ray beam |
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when projectile electrons strike & interact with target atoms what interactions occur
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conversion of KE to: thermal energy (heat), infrared radiation (heat),
x-rays |
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how much energy (KE)is converted to heat
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99%
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what 3 interactions occur when a projectile electron interacts with a target atom
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heat (excitation), characteristic x-rays, bremsstruhlung x-ray
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efficency of x-ray production increases when you increase
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kVp
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production of anode heat is directly effected by increasing
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current mA double mA double heat
(increased kVp has a aproximate effect) |
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emission of characteristic x-rays occur when
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an electron drops from an outer to an inner shell
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where is projectile interaction during characteristic interactions
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with inner shell electron
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Brem interactions occur where
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with nuclear field "braking radiation" slowed & changed direction
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how much KE is lost during brem & characteristic interactions
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brem: all, none, inbetween
Characteristic: of the target material (fixed) |
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characteristic x-rays have a _____emission spectrum
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discrete
(fixed energies) |
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Brem x-rays have a range of energies that form a _______ emission spectrum
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continuous
(wide range of energies) |
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wheer is the greatest # of x-rays (energy level) on the spectrum for brem x-rays
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at 1/3 the max energy
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Min wavelength of x-ray emission corespods to the max x-ray energy, and it is equal to
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kVp
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max x-ray energy is associated with min x-ray ___
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wavelength
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E = hf
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the energy of an x-ray is equal to the product of its frequency (f)& planks constant (h)
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the energy of a photon is directly proportional to its ___
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frequency
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x-ray energy is inversely proportional to its ______
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wavelength
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when the spectrum shifts right what happens
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the effective energy or quality of the x-ray beam is higher
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a larger area under the curve means
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a higher x-ray intensity or quantity (amplitude)
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how is the spectrum changed when mA is increased
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the amplitude (increases)is changed but not the shape
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a change in kVp will have what effect on the emission spectrum
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the spectrum shifts right to the high energy side
the amplitude also increases |
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what happens to the emission spectrum when filtration is added to the tube
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reduced intensity (amplitude) curve goes down & right increased effective energy
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what happens to the x-ray spectrum when atomic # increases
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shift right and up, increased quantity & quality
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Why is 3 phase or high frequency = 12% increase in kVp or almost double mAs compared to single phase
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reduced voltage ripple
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which kind of generator has the lowest voltage ripple
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high frequency
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4 factors that influence x-ray emission spectrum
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low e- = low x-rays, sucesive interation cause low energy x-rays, filtration removes low energy (more likely)
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Increase in mAs result
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in higher quantity
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Increase in kVp result
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in higher quantity & quality
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Added filtration results in
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lower quantity & higher quality
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increase in higher target Z # results
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in higher quantity & quality
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higher ripple results in
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lower quantity & quality
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