Ch. 8 X-ray Production Flashcards
What is the primary difference between X-rays and gamma rays?
X-rays are man-made, while gamma rays are naturally occurring
This distinction is important in understanding the origins of these types of radiation.
What are the three main components of an X-ray equipment system?
- Operating console
- High voltage generators
- X-ray tube
These components work together to produce X-rays.
How far does the thermionic cloud travel from the cathode to the anode?
Approximately 2 cm (~1 in)
This distance is crucial for the kinetic energy of the electrons.
What are incident electrons also referred to as?
Projectile electrons
This term describes the electrons moving from the cathode to the anode.
What happens to the linear energy of incident electrons when they strike the anode?
It is converted to either heat or X-ray photons (99% / 1%)
Also known as a target interaction
What controls the speed of electrons traveling from cathode to anode?
Kilovoltage peak (KVp)
The KVp setting affects the kinetic energy of the electrons.
What is the relationship between the speed of incident electrons and X-ray photon energy?
The greater the speed of the incident electrons, the higher the X-ray photon energy
What is the relationship between the number of electrons burned off during thermionic emission and the number of X-ray photons produced?
The number of electrons is directly related to the number of X-ray photons
This means more electrons result in more X-ray production.
What does mAs stand for in X-ray production?
Milliamperage seconds
This measurement controls the amount of current and time in the X-ray production process.
What is the effect of heat produced during the interaction of incident electrons with tungsten?
99% of the kinetic energy is converted to heat
This heat is a byproduct of the interaction, with no ionization occurring.
What causes heat to be released when incident electrons interact with tungsten atoms?
Excitation of outer shell electrons of tungsten atoms
This excitation causes the atoms to vibrate, releasing energy as heat.
True or False: Ionization occurs in tungsten during the production of heat from incident electrons.
False
The process described does not involve ionization of the tungsten atoms.
Name the two types of x-ray photons.
- Bremsstrahlung Interaction
- Characteristic Interaction
What is the effect of the kVp on x-ray production?
The type of x-ray being created is dependent on the kVp that is used
What does ‘Brems’ mean in the context of x-ray production?
‘Brems’ means braking or slowing
Does Bremsstrahlung Interaction involve ionization of the tungsten atom?
No ionization of the tungsten atom occurs
Describe the interaction during Bremsstrahlung.
The incident electron interacts with the force field of the nucleus of the atom
What happens to the incident electron in Bremsstrahlung Interaction?
The incident electron is deflected from the nucleus, causing it to brake or slow down
What is emitted as a result of energy loss in Bremsstrahlung Interaction?
An x-ray photon
How is the energy of the x-ray photon determined?
The energy of the x-ray photon is determined by the kinetic energy of the incident electron
What percentage of the primary beam is made up of Bremsstrahlung rays when using 80-100 KVp?
80-90% of the primary beam
What happens to the x-ray photons created each time the incident electron interacts?
They create photons with less and less energy
At what KVp level do Bremsstrahlung rays make up 100% of the beam?
At 68 kVp or lower
Fill in the blank: The primary beam is __________ due to the varying energies of x-ray photons.
heterogeneous
True or False: Bremsstrahlung Interaction can occur multiple times with the same incident electron.
True
What occurs during characteristic interactions?
The incident electron interacts with a k-shell electron, knocking it out of orbit, resulting in ionization of the atom.
What is the electron binding energy of the K-shell electron in a tungsten atom?
69.5 KeV
What happens when an electron is removed from the K-shell?
A hole is created, making the atom very unstable.
What process is termed characteristic cascading?
The process of outer shell electrons dropping down to fill the inner shell hole, creating an x-ray photon.
What type of emissions are K-shell emissions?
X-rays that have diagnostic quality energy to contribute to the primary beam.
Why is there a 2.5 mm Al equivalent tube filtration in equipment operating over 70 KVp?
To filter out low-energy emissions that would only cause biological harm.
What is the effect of filtration on the intensity and energy of the beam?
Filtration decreases the intensity of the beam but increases the average energy of the beam.
What does ‘hardens the beam’ mean?
It means making the beam stronger and of higher energy.
What percentage of the primary beam is made up of characteristic rays when using 80-100 KVp?
10-20%
What percentage of characteristic rays is present until 70 KVp is used?
0%
What does KVp stand for in the context of radiography?
Kilovolt peak energy
What does mAs represent in radiography?
The number of photons in the primary beam.
(The quantity of the primary beam)
Fill in the blank: The characteristic interactions are influenced by the _______ of the incident electron.
[kinetic energy]
