X-ray Production; Bremsstrahlung & Characteristic

which three of the following are required for xray production?

source of elections, means of rapidly accelerating electrons, means of rapidly decelerating electrons

which component of the xray tube serves as the source of free electrons?

cathode filament

what technical factor is responsible for accelerating electrons through the xray tube?

kilovoltage peak (kVp)

thermionic emission is the process within the xray tube directly responsible for creating:

free electrons

which component of the xray tube becomes negatively charged during an xray exposure?

cathode filament

what technical factor is primarily responsible for controlling the energy of the xray beam?

kilovoltage peak (kVp)

what condition is required to induce thermionic emission within the cathode filament?

high current

An exposure of an obsese patient results in inadequate receptor exposure. What technical factor should be modified to increase the energy and penetrability of the xray beam?

kilovoltage peak (kVp)

a portable chest xray demonstrates excessive exposure. How can the technologist decrease the intensity of the xray beam while maintaining the same beam energy?

decrease milliamperage (mA)

during an attempted xray exporsure, the xray tube fails to create any xray photons. Which of the following conditions is most likely to explain this failure?

breakage of the cathode filament

Bremsstrahlung radiation is created within the xray tube when high energy electrons interact with which of the following?

electric field of the nucleus

Bremsstrahlung is a german term defined as

braking radiation

the energy of a bremsstrahlung photon is dependent on which two of the following variables?

energy of the incident electron; proximity of the incident electron to the nucleus

the maximum energy of a bremsstrahlung photon that can be created during an xray exposure is equal to the

energy of the incident electron

the maximum energy of a bremsstrahlung photons is controlled by which technical factor?

tube potential

during an xray exposure an incident electron strikes the anode with an energy of 84 keV and passes very close to the tungsten nucleus. What is the approximate energy of this electron as it exits the atom?

1 keV

during an xray exposure an incident electron strikes the anode with an energy of 110 keV and passes very close to the tungsten nucleus. What is the approximate energy of the photon created by this interaction?

110 keV

the energy of a bremsstrahlung photon is equal to the

loss of kinetic energy as the electron brakes and changes directions

an exposure taken with an 80 kVp would have an xray energy spectrum with a maximum photon energy of

80 keV

during an xray exposure an incident electron strikes the anode with an energy of 90 keV and passes very far from the tungsten nucleus. The resulting photon energy is 30 keV. What is the approximate energy of the electron as it exits the atom?

60 keV

what name is given to the innermost electron shell within an atom?

K shell

electron binding energy is defined as the

energy required to remove an electron from orbit

how much energy is required to remove a k shell electron from a tungsten atom?

69.5 keV

during the process of characteristic xray production, the cascade effect refers to the

electron transfer from the outer shell to the inner shell

a characteristic photons energy depends on which two of the following variables?

energy of the incident electron; binding energy of orbital electrons

what are the majority of xray photons in an xray beam classified as?

bremsstrahlung radiation

what photon energy is produced by a tungsten anode if a K shell electron vacancy is filled by an M shell electron? The approximate electron binding energies for Tungsten are as follows: K shell = 69.5 keV; L shell = 12.0 keV; M shell = 3.0 keV; N shell = 0.5 keV

66.5 keV

the most useful characteristic xray photons are produced when incident electrons interact with which of the following?

inner shell electrons

the following graph is the photon energy spectrum for an exposure created with a technique of 80 kVp and 10 mAs using a tungsten anode. What portion of the graph represents k shell characteristic photons?

C

the following graph is the photon energy spectrum for an exposure created with a technique of 80 kVp and 10 mAs using a tungsten anode. What approximate energy of photons at position C of the spectrum?

69 keV

electrons are produced at the

filament

the term for electron production

thermionic emission

the technical factor responsible for electron acceleration

kVp

the measurement of tube current

mA

the controller of xray intensity (quanitity)

mAs

the controller of photon penetrability (energy)

kVp

brem radiation is produced by

the slowing of an incident electron

the charge of the nucleus

positive

the inner shell of an atom

k shell

brem radiation involves

an incident electron and the nucleus of an atom

a brem photon is the result of

the energy difference between the incident electron as it passes (slows) near the nucleus

two interactions that produce xrays

bremss and characteristic

the closer to electron is to the nucleus

the stronger the binding energy

characteristic xray can be defined as

total removal of an electron

characteristic xray production involves

incident electron and inner shell electron

the process of adding or removing electrons from an atom is

ionization

the cascade effect describes

the movement of an electron from an outer shell into an inner shell

the binding energy and unit of a tungsten atoms inner shell

69 keV

the lowest kv setting possible for producing characteristic radiation

69 kVp

three ways projectile electrons can interact at the target

heat; creating brems xrays; creating characteristic xrays

what do electrons lose as they slow down

kinetic energy

below what keV will all radiation produced be brems

69 keV

interacts with inner shells electrons of the target atom rather than with the outer shell electron

projectile electron

from which shell are characteristic xrays useful and contribute to diagnostic radiographs?

K shell

what does the interaction start with electron or photon?

electron

what type of xrays form a continuous emission spectrum?

brems

what ype of xrays form a discrete emission spectrum?

characteristic

at 100 kVp, what percent are brems?

80%

xray is

heterogeneous; has many energy levels; polyenergenic

xray is not

homogeneous; has same energy levels; monoenergenic

the maximum energy of the brems xray is the same as the

tube potential

below what keV do photons get filtered?

20

photon gamma spectroscopy

a visual demonstration of an xray beams energies

what type of interaction is this?

brems

what type of interaction is this?

characteristic

the reduction in xray beam intensity as a result of absorption and scatter in matter

attenuation

what is attenuation dependent on?

part thickness; tissue density, atomic number, beam energy (kVp)

the xray beam coming from the tube before it interacts with matter

primary beam

the attenuated beam - what is remaining in the beam after it passes through matter

reminant beam

the three things that occur when an xray beam passes through matter attributing to attenuation

transmission, absorption, scatter

what determines the energy of the photon produced in brems?

by how close the incident electron is to the nucleus

what determines the energy of the photon produced in characteristic?

by the difference in binding energy between the two electron shells involved in the transition

what is the setting that controls the quality and max energy of the xray beam?

kVp

relationship between kVp and keV in the primary beam?

kVp sets max potential energy and keV will match peak setting but the average energy of all photons in primary beam will be 1/3 of the set kVp

what type of interaction is this?

characteristic