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38 Cards in this Set
- Front
- Back
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Target interactions all occur within ___ to ___ mm of target surface.
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0.25 to 0.5
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Target Interactions:
Two types of x-ray production processes |
Bremsstrahlung and Characteristic
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Target Interactions
Bremsstrahlung and Characteristic: ___ and ___ ___ of x-rays from these processes are ___ and influence ___ of ___ ___. |
Amount; energy distribution; different; appearance; final image
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Approximately ___% of kenetic energy of ___ ___ is converted to heat.
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99%; projectile electrons
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Projectile electrons interact with ______ ______ of the target atoms, but do not transfer enough sufficient energy to ______ them causing them to emit ______ ______.
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outer-shell electrons; ionize; infrared radiation
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Only approximately 1% of ___ ___ ___ ___ is used for production of x-radiation.
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projectile electron kinetic energy
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keV stands for:
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kiloelectron volts
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Distributed from zero to E(max)
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keV
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The maximum energy of the projectile electrons
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E(max)
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kVp stands for:
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kilovoltage peak
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Voltage applied to the x-ray tube
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kVp
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Equal to the energy of the projectile electrons
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kVp
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Equal to the maximum energy of the x-rays, called E(max)
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kVp
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Also referred to as "Brems"
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Bremsstrahlung
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German word for braking or slowing radiation
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Bremsstrahlung
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Produced when projectile electrons are slowed down in the anode
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Bremsstrahlung
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Incident electrons interact with electrostatic force field of the nucleus
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Bremsstrahlung
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Incident electrons have a ___ charge and are attracted to ___ charged nucleus.
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negative, positive
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When ___ ___ get close to nucleus, the powerful force field is too great to penetrate.
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incident electrons
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Bremsstrahlung: Incident Electron
Force field makes electrons ___ ___ or ___ and causes the electron to change ___. |
slow down; brake; directions
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Left with reduced kinetic energy in different direction.
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Bremsstrahlung Interactions
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The loss of kinetic energy reappears as an x-ray
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Bremsstrahlung Interactions
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Bremsstrahlung Interactions:
Accounts for ___-___% of the beam. |
85-100%
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Bremsstrahlung Interactions:
X-rays are produced at ___ ___ because electrons are ___ ___ at different rates. |
different energy; slowed down
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Bremsstrahlung Interactions:
The ___ the electron pass by the nucleus, the ___ the production of energy photon x-rays. |
closer, higher
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Emitted when an outer shell electron fills the inner-shell void. An x-ray photon is released in this interaction.
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Characteristic x-rays
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Electrons moving into the holes created during characteristic interaction until there is only a hole in the outer shell.
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Characteristic cascade
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Only electron that drops into ______ will contribute to the beam and are useful for imaging.
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K-shell
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Kinetic energy must overcome binding energy
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Occurs in techniques using 70kVp or higher
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Incident electron interacts with K-shell electron
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Incident electron continues in slightly different direction
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Change in mA, time, or mAs
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Change beam amplitude
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Change in kVp
Changes beam amplitude and average energy |
Due to increase in kinetic energy provided to incident electrons.
No Increase in electrons striking the target |
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Combined form spectrum
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Brems and characteristic emissions
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Diagnostic X-ray range
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Most photons are produced by the Brems
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Characteristic will not compromise any of useful beam until
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kVp is above 70
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Between 80 and 100 kVp, __-__% of primary beam is Brems
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80-90%
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Between 80 and 100 kVp, __-__% of primary beam is Characteristic
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10-20%
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Both emissions combine to form primary beam spectrum
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Brem and Characteristic
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