Shared Flashcard Set

Details

Radiographic Physics 1 - Unit 5
Interactions, Attenuation
28
Medical
Undergraduate 3
07/23/2013

Additional Medical Flashcards

 


 

Cards

Term
Interaction responsible for contrast
Definition
Photoelectric
Term
Attenuation
Definition
the reduction of the number of x-ray photons in a beam as a result of absorption or scatter production
Term
low energy photons interact with:
Definition
whole atom
Term
moderate energy photons interact with:
Definition
electrons
Term
high energy photons interact with:
Definition
nucleus
Term
Name 5 interactions the occur within the patient
Definition
1. Coherent
2. Photoelectric
3. Compton
4. Pair Production
5. Photodisintegration
Term
Photoelectric Interaction
Definition
Photon interacts with an atom in the body, interacts with an inner shell and bounces an electron out.
Photon is completely absorbed.
Term
Interaction in which photon is completely absorbed.
Definition
Photoelectric
Term
What determines probability of the PE interaction?
Definition
1. Photon energy - low energy=high prob
2. Z# of atom - high Z#=high prob
Term
Compton Interaction
Definition
Interaction between an x-ray and and a loosely bound outer-shell electron that results in ionization and x-ray scattering. Energy of incident photon is not completely absorbed, but scattered.
Term
Interaction dependent on Z#
Definition
Photoelectric
Term
Interaction not dependent on Z#
Definition
Compton
Term
Coherent Scattering
Definition
A low energy photon interacts with an atom and has the same energy going in and going out. Ionization does not occur. Does not have diagnostic value.
Term
Other names for Coherent Scattering
Definition
Classical, Unmodified, Raleigh and Thompson
Term
Interaction in which ionization does not occur
Definition
Coherent Scattering
Term
Pair Production
Definition
An interaction in which a high-energy photon hits the nucleus of an atome within the body and is completely absorbed. The result is the ejection of one positron and one negatron. The positron joins with a free electron in an annhilation reaction and 2 photons are emitted.
Term
Photodisintegration
Definition
Process by which very high energy x-rays can escape interaction with electrons and the nuclear electric field and can be absorbed directly by the nucleus which causes it to "blow apart".
Term
What energy is required for Pair Production?
Definition
At least 1.02 MeV
Term
What energy is required for Photodisintegration?
Definition
At least 10MeV
Term
Differential Absorption
Definition
The principle that explains the difference in the amount of x-ray absorption between materials, which results in the formation of a radiologic image.
Term
Most scatter in a radiologic image is due to:
Definition
the Compton effect
Term
If the scattered x-ray has the same wavelength and frequency as the incident x-ray, the interaction is called:
Definition
Coherent scatter
Term
If the incident photon is completely absorbed when an electron is knocked out of an atom, the interaction is called:
Definition
Photoelectric Effect
Term
What radiation is emitted when an electron drops from an outer shell to an inner shell?
Definition
Characteristic Radiation
Term
In what interaction does the incident photon give only part of its energy to a bound electron?
Definition
Compton Effect
Term
The PE occurs with _____ shell electrons.
Definition
inner
Term
The Compton Effect occurs with _____ shell electrons.
Definition
outer
Term
The formula that explains how an electromagnetic wave can disappear and leave 2 particles in its place?
Definition
E=mc^2
Supporting users have an ad free experience!