Upgrade to remove ads
Principles of Radiographic Imaging chapter 7
Terms in this set (35)
high speed electrons from the cathode strike the anode target
X rays are produced when:
the anode target (2 cm distance) traveling nearly speed of light
and are called incident electrons
The electrons that form the thermionic cloud around the filament arrive at ______ and are called _________.
less than 1 percent
The target interactions that produce the x ray photons consist of ____ of the total kinetic energy of the incident photons
Over 99.8 percent
over ____ of the kinetic energy of incident photons is converted to heat
excite the outer shell electrons and they will emit infrared rad. as heat
Incident electrons have too much kinetic energy to transfer to orbital outer electrons and cause ionization, instead they ____.
electron kinetic energy and the binding energy of the electron shells
The interaction that will occur depends on ___.
an incident electron interacts with force field of the nucleus causing the incident electron to slow down, thus diverting the electrons course. the electron loses energy and changes direction. the energy lost is a bremsstrahlung photon & the photon energy is half the difference between the entering and exiting kinetic energy of a electron
mutual attraction and powerful nuclear force;
slows down, brakes
Brems interaction requires two things
x ray photon
The energy lost during braking (Brems interaction) is emitted as a _____.
the difference between entering and exiting kinetic energy of the electron
The energy of the Brems interaction photons is :
inverse relationship; determined by the distance the electron is from the nucleus;
ex: at large distances, little kinetic energy is lost= low energy brems radiation
at closer distances, more ke is lost=high energy brems
The amount of kinetic energy lost by the incident electron in a brems interaction is a ____ relationship and is determined by_____.
Name what happens differently at large and close differences.
loss of all electron's kinetic energy=max energy photon
In Brems, an electron could also have direct impact with the nucleus, resulting in_____; but because the nucleus is so small this chance is low.
the reactions of electrons dropping into holes created during a characteristic interaction until there is only a hole in a outer shell
the incident electron interacts with an inner-shell electron knocking out the inner shell electron and continuing in a slightly different direction which creates a hole in a inner shell, making the shell unstable
difference in the binding energy of the outer versus inner electron shells; outer shell electrons have higher energy and have to give off the extra as they fill a lower shell electon's spot
The energy for emissions of characteristic photons is:
Only interaction at the ____ level produce characteristic photons and contribute to diagnostic range x ray beams
occurs when k-shells reach the effective energy range of 69 keV.
the electrons from the thermionic cloud that arrive at the anode target
takes place when the electrons strike their target or focal point
Total amount of kinetic energy used to produce target interations
Less than 1 percent
Average primary beam KeV energy
30-40 percent of the kVp
What is the X-ray emission spectrum graph?
Illustrates the relationship between the two target interactions within the primary beam.
The total amount of kinetic energy converted to heat
Sufficient electron shells to produce relatively high-energy characteristic photons
the maximum possible energy for any photon that exits the x-ray tube.
When an x-ray beam passes through filtering materials
the intensity of the beam, and
the average photon energy
When are X-ray photons are produced?
The high-speed electrons from the cathode strike an anode target.
the mass or speed of the incident electrons
the quality (energy) and quantity (number) of photons produced
What two target interactions produce x-ray photons?
Bremsstrahlung (brems) and characteristic interactions.
When an electron is knocked out of an inner shell so another drops into its place resulting in the emission of an x-ray photon.
It is called a characteristic photon because...
The energy is exactly the difference between the binding energy of the outer and inner shells between which the electron dropped.
Most x-rays in the diagnostic range are produced by what interaction?
Bremsstrahlung (Brems) Target Interaction
Relationship between increasing/decreasing mAs and kVp and high energy photons
Brems target interactions
within the diagnostic x-ray range most photons 80/90%are produced by____.
kVp above 70; K shell
Characteristic photons will not comprise any of the useful beam until _____; and ____ shell emissions will be the only ones within diagnostic range
Other sets by this creator
Bontrager Ch 17
The Grid - Chapter 18
Bontrager chapter 14
bontrager chapter 14