Fluoroscopy ARRT
Exam Study guide(446
questions and
answers)
what mag modes are available? - answer if you have a 16" II, you can
have 12,9,6, and 4.5 "
Compton effect - answer hits the outer electron, incomplete transfer of
energy, electron released and a low energy xray is deflected
photoelectric absorption - answer x-ray totally absorbed by inner shell
electron, x-ray overcomes binding energy and knock out the electron
and an outer shell electron takes it place. When the outer electron
moves to its new place, a characteristic x-ray is formed
what is the product of photoelectric absorption? - answer electron
flying , characteristic x-ray, and positive ion
,coherent scatter - answer aka Thompson scatter, Rayleigh scatter or
classical scatter. x-ray is absorbed by entire atom and is sent off in
another direction with no energy loss
does coherent scatter result in patient dose? - answer No, this reaction
only causes excitation of the atoms shells, but there is not energy
transfer nor does the x-ray lose energy ( isotropic)
what is the chance of coherent scatter occurring? - answer 5%
attenuation - answer the drop of intensity of the beam due to
absorption and scatter
photoelectric interaction is dependent on - answer Z^ 3 and 1/E^3
as photon energy increases there is more - answer penetration and a
decrease in tissue interactions
Compton is dependent on - answer energy level ( the higher it is, the
greater probability of occurrence), electrons/ gram
attenuation equation - answer I= Io e^ (-ux)
initial energy x e^( attenuation factor x tissue thickness)= resulting
energy
,initial energy- resulting energy= absorbed energy
u ( tissue attenuation coeffient) is dependent on - answer keV and
material
what is the source of free electrons? - answer cathode
what is the cathode made of? - answer 98% tungsten, 1-2% thorium
in what direction are electrons accelerated? - answer cathode to anode
how do we focus electron? - answer we use a focusing cup made of
nickel that has a greater negative charge. This negative charge repels
and squishes the electrons that are made from thermionic emission
how does deceleration occur in electrons? - answer the closer to the
nucleus the electron is, the more attraction there is and as a result it
slows down faster. More energy is transferred to the xray and it has a
higher energy as well. If the electron is far, it wont slow down as much,
it will lose less energy and will result in a low energy electron.
what is the cathode filament made of? - answer Tungsten
bremsstrahlung interaction - answer 99% heat, 1% x-ray
, aka braking radiation, cathode electrons hit anode electrons. Electron
that are closer to the nucleus slow down more and lose more energy
but create higher energy electrons. Electrons that are farther away slow
down less, lose less energy and create low energy x-rays. They retain
enough energy to keep having more interactions
(electrons are more likely to hit the outer rim of the anode)
characteristic interactions - answer made 2 ways
1)cathode electrons hit anode electrons
2) PE effect from x-ray to electron interactions
which interactions occur in the tube? - answer bremsstralung
what interactions occur in the body? - answer PE, Compton, Coherent
scatter
what happens when we increase KeV? - answer the chance of Compton
effect increases, and the ratio between CS and PE also increases
equations for frequency and wavelength - answer c= speed of light=
3x10^8 m/s
Hertz= cycles/s
frequency = speed of light/ wavelength
v = c/ upside down Y
Exam Study guide(446
questions and
answers)
what mag modes are available? - answer if you have a 16" II, you can
have 12,9,6, and 4.5 "
Compton effect - answer hits the outer electron, incomplete transfer of
energy, electron released and a low energy xray is deflected
photoelectric absorption - answer x-ray totally absorbed by inner shell
electron, x-ray overcomes binding energy and knock out the electron
and an outer shell electron takes it place. When the outer electron
moves to its new place, a characteristic x-ray is formed
what is the product of photoelectric absorption? - answer electron
flying , characteristic x-ray, and positive ion
,coherent scatter - answer aka Thompson scatter, Rayleigh scatter or
classical scatter. x-ray is absorbed by entire atom and is sent off in
another direction with no energy loss
does coherent scatter result in patient dose? - answer No, this reaction
only causes excitation of the atoms shells, but there is not energy
transfer nor does the x-ray lose energy ( isotropic)
what is the chance of coherent scatter occurring? - answer 5%
attenuation - answer the drop of intensity of the beam due to
absorption and scatter
photoelectric interaction is dependent on - answer Z^ 3 and 1/E^3
as photon energy increases there is more - answer penetration and a
decrease in tissue interactions
Compton is dependent on - answer energy level ( the higher it is, the
greater probability of occurrence), electrons/ gram
attenuation equation - answer I= Io e^ (-ux)
initial energy x e^( attenuation factor x tissue thickness)= resulting
energy
,initial energy- resulting energy= absorbed energy
u ( tissue attenuation coeffient) is dependent on - answer keV and
material
what is the source of free electrons? - answer cathode
what is the cathode made of? - answer 98% tungsten, 1-2% thorium
in what direction are electrons accelerated? - answer cathode to anode
how do we focus electron? - answer we use a focusing cup made of
nickel that has a greater negative charge. This negative charge repels
and squishes the electrons that are made from thermionic emission
how does deceleration occur in electrons? - answer the closer to the
nucleus the electron is, the more attraction there is and as a result it
slows down faster. More energy is transferred to the xray and it has a
higher energy as well. If the electron is far, it wont slow down as much,
it will lose less energy and will result in a low energy electron.
what is the cathode filament made of? - answer Tungsten
bremsstrahlung interaction - answer 99% heat, 1% x-ray
, aka braking radiation, cathode electrons hit anode electrons. Electron
that are closer to the nucleus slow down more and lose more energy
but create higher energy electrons. Electrons that are farther away slow
down less, lose less energy and create low energy x-rays. They retain
enough energy to keep having more interactions
(electrons are more likely to hit the outer rim of the anode)
characteristic interactions - answer made 2 ways
1)cathode electrons hit anode electrons
2) PE effect from x-ray to electron interactions
which interactions occur in the tube? - answer bremsstralung
what interactions occur in the body? - answer PE, Compton, Coherent
scatter
what happens when we increase KeV? - answer the chance of Compton
effect increases, and the ratio between CS and PE also increases
equations for frequency and wavelength - answer c= speed of light=
3x10^8 m/s
Hertz= cycles/s
frequency = speed of light/ wavelength
v = c/ upside down Y
