What is the reduction of the number of x-ray photons in a beam?
The definition of attenuation is the result of x-ray photons interacting with ____, and therefore giving up their energy.
entire atom, orbital electron, or nucleus
What are the 3 things a x-ray can interact with?
Generally, low energy photons interact with what?
Generally, moderate energy photons interact with what?
Generally, high energy photons interact with what?
High energy, small wavelength x-rays interact with (small / large) things?
Orbital electrons that are close to the nuclues are described as "___".
Orbital electrons that are further away from the nucleus are described as "____".
coherent scater, PE absorption, compton scatter, photodisintegration, and pair production
What are the 5 basic interactions betwen x-rays and matter?
What interaction occurs when the incident photon energy is completely absorbed by an inner shell electron?
Which interaction is most likely to occur when the x-ray photon has just slightly more energy than the binding energy of a K or L-shell electron?
For PE absorption a photon goes in and ____ comes out.
What is formed in PE absorption when an electron is ejected from the atom?
binding energy + kinetic energy
The photoelectron energy can be determined how?
kinetic energy, mass, and reabsorbs quickly
What are the 3 main characteristics of the photoelectron?
A photoelectron reabsorbs within how much of tissue?
What is formed in the inner orbital when a K shell is ejected out of it's orbit?
What is the process of a vacancy being filled by an outter electron, the electron undergoes an energy level change, and a photon is emitted?
The emitted photon in PE absorption is called what?
_____ _____ is radiation that originates from irradiated material outside of the x-ray tube.
Characteristic photons are emitted as a result of which interaction?
If a PE absorption occurs with a low Z# tissue, it will result in (high / low) secondary radiation.
IF PE absorption occurs with a high Z# tissue, it will result in (high / low) secondary radiation.
greater than or equal to
For PE absorption, the incident photon energy must be ___________________ the binding energy of an inner-shell electron.
AS photon energy increases, chance of PE interaction (increases / decreases) dramatically.
inverse cubed relationship
Photon energy and chance of PE interaction has what kind of relationship?
PE absorption is more likely to occur in elements with a (higher / lower) Z#.
Low Z# atoms experience PE interactions with which shell/s?
K, L, or M-shell
High Z# atoms experience PE interaction within which shell/s?
Which interaction involves low energy photons?
Coherent scattor occurs only if the energy of photons is below ____.
thomson and rayleigh
What are two types of coherent scatter?
What type of coherent scatter interacts with a single outer shell electron?
What type of coherent scatter interacts with all the electrons in an atom?
During a coherent interaction, electrons are ____ or vibrate at photon frequency.
What is emitted after a coherent interaction?
In coherent interactions, the released photon has energy equal to what?
What interaction occurs when an incident photon interacts with an outer-shell, loosely bound electron and ejects it?
With what reaction does ionization not occur?
What is the name of the ejected electron in a compton interaction?
recoil electron and scattered photon
The incident photon energy is distributed between what in a compton interaction?
In a compton interaction, the energy transferred to the recoil electron affects the angle and energy of what?
Where is the worst place to stand in relation to the patient during an exposure?
Where is the best place to stand in relation to the patient during an exposure?
For pair production to occur, the incident photon energy must be _____ or greater.
In pair production the photon energy is absorbed by what?
negatron and positron
What is the name of the two electrons released by the nucleus in a pair production?
What happens when the positron is accelerated and collides with a free electron?
two .511 MeV photons
What is the end result of a pair production?
Pair production is not a significant interaction until energies of ____ are being used.
What interaction occurs when an extremely high enegy photon interacts with the nucleus and the energy is absorbed and released as an alpha particle?
Photodisintegration only occurs at ____ or greater.
What is released in photodisintegration?
As kVp increases the number of photons transmitted without interaction ____.
Within the attenuated beam, as kVp increases PE absorption ____ and compton scatter ____.
Which interaction typically predominates within diagnostic x-ray energy range?
lower energy ranges and higher Z#s
PE absorption interactions predominate in which 2 circumstances?
When PE absorption predominates the image will have a (short scale / long scale) contrast.
When compton scatter predominates the image will have a (short scale / long scale) contrast.