X - Ray (photon) Interactions Flashcards
When a beam passes through matter, it undergoes a process called ____
Attenuation
The x ray photon interacts with matter and ___ energy through these interactions
Loses energy
ATTENUATION
photons can interact with:
Whole atom
Orbital electron
Directly with the nucleus
In diagnostic imaging, interactions occur mostly with the ____
Orbital electrons
The ___ shell electrons possesses the highest binding energy
K she’ll
___ shell electrons are more tightly bound to the nucleus in high atomic number elements
K shell
It takes a ____ energy photon to remove a k shell electron from tungsten than calcium but ___ energy to remove a k shell electron from fat or muscle
Higher energy
Less energy
Electrons ____ from the nucleus are NOT bound as tightly, they require ___ energy to remove them from their orbit
Farther, LESS energy
The ___ an electron is from the nucleus, the more energy it needs to remain in orbit
Farther
5 basic interactions between X-ray and matter
Photoelectric absorption
Coherent scattering
Compton scattering
Paid production
Photo disintegration
An incident photon possessing slightly greater energy than binding energy ejects a k shell electron and the incident photon gets totally absorbed.
What am I?
Photoelectric absorption
_________: Results in an ionized atom (+) and photoelectron (-) with kinetic energy equal to the difference between the incident photon energy and the binding energy of the inner shell
Photoelectric absorption
The electron transfer from an outer shell release energy in the form of a characteristic photon known as ___
Secondary radiation
Characteristic radiation that was produced at the target is called ____
Primary radiation
The incident ______ must be greater than the binding energy of the inner shell electron
X-ray photon energy
A ___ kev X-ray photon will not be able to remove the k shell electron from an atom of midline, which has a binding energy of 33.2 keV
30
The possibility of ____ is more likely to occur when x ray photon energy and electron binding energy are close in energy to one another
Photoelectric interaction
The possibility of _____ is more likely to occur with an electron that is more tightly bound in its orbit; high atomic number
Photoelectric interaction
In high atomic number elements, photoelectric interactions occur in ___ , ___ and ___ shells
(Unlike characteristic interactions in target, only k)
K L and M
As we ____ our kvp we are ____ the possibility of photoelectric absorption because we are increasing the beam energy to a point that may be greater than the binding energies of the atoms within the subject
INCREASE, DECREASING
If the atomic number of the object we are x raying is higher (bone vs soft tissue) there is a ____ chance that the photon will undergo a photoelectric interaction
Greater
(Direction relationship)
Incident photons interact with a loosely bound outer shell electron, part of the energy is used to remove the electron from the shell
What am I?
Compton scatter
Dislodged electron called the Compton or ______ electron
Recoil
Remaining photon energy exits the atom in a different direction called ____
Scatter photon
Scatter photon possesses ___ energy than the incident
Less
** lower frequency and longer wavelength than the incident photon **
_____ retains most of the original energy because little energy is. Refer to remove an outer shell electron
Incident photon
______ photon will continue to interact with other atoms until it is eventually absorbed photoelectrically
Scattered
_____ electron or Compton electron is available as a free electron to fill a shell Hole created by another ionizing interaction
Recoil
Compton scatter:
Incident photon energy = sum of the energy of the scattered photon + binding energy of the shell + energy of recoil electron
The amount of energy retained by scattered photons is dependent on the _____
Initial energy of the photon
The ___ the incident energy, the greater the energy of the scattered photon
Higher
____ deflection angle means that photon retained most of its original energy
Small
____ deflection angle means that the photon gave up most of its original energy
Large
When a scattered photon is deflected back 180 degrees it is called ____
Backscatter radiation
____ radiation is the primary cause of occupational radiation exposure
Scatter
Scatter adds unwanted exposure to the image called ____
Radiation fog
A device called a ___ is used to remove unwanted scatter
Grid
Compton scatter does NOT depend on atomic number like photoelectric interactions
True or false?
True
More matter, ____ scatter
More
Occurs between very low energy X-ray photons and matter
AKA classical, unmodified and electric
What am I?
COHERENT scattering
List 2 types of coherent scattering
Thompson
Rayleigh
What is Thompson scattering?
Involves single electron
What is Thompson scattering?
Involves single electron
What is Rayleigh scattering
Involves ALL the electrons of the atom
What is Rayleigh scattering
Involves ALL the electrons of the atom
A photon with energy less than ___ kev interacts with atom causing the electrons to vibrate at the same frequency as the incident photons
(Coherent scattering)
10
(Coherent scattering)
The excited aroma immediately ___ the energy by producing a secondary photon with the ___ energy, frequency and wavelength as incident photon but traveled in different directions
Releases, same
Results in a scatter photon only
No ionization
Outside the useful range of diagnostic imaging
A small amount reaches the IR
What is this?
Coherent scattering
Reaction between an extremely high energy photon (>10 mev) and the nucleus
High energy photon strikes the nucleus and all energy is ABSORBED
What am I?
Photo disintegration
