9. Electromagnetic radiation Flashcards
Define radiation:
-The transmission of energy through waves or particles
-Can be ionizing or nonionizing
Define ionization:
e- travelling though the tube interacting with an e- in the tungsten and knocking it out of orbit creating a cascading affect
What are the 4 major types of radiation?
- Electromagnetic (EMR)
- Particulate; when alpha, and beta radiation is produced (radioactive decay in nuclear radiation)
- Acoustic; (ultrasound)
- Gravitational
Define electromagnetism:
Charges in motion create electromagnetic waves
(Energy travels as a sinusoidal wave)
What is Wave-Particle Duality?
EMR acting as a wave and acts like a particle
What is amplitude? What happens when it gets higher?
- Maximum field strength (how high and low the waves get)
- Higher amplitude = higher intensity
Define wavelength:
- Distance between same points in wave
What is reflection?
Bouncing off of an interface
What is refraction?
Change in direction from change of speed
What type of wave-like interaction do x-rays exhibit?
Diffraction
What is diffraction?
Wave bends around sharp corners or borders and is not absorbed to create a pattern (slight change in direction)
x rays do this
What are the two types of interference?
- Constructive: (add together)
- Destructive (cancel out-happens in 3-phase generators if we had them on the same circuit)
Define wave theory:
Effect between electrical and magnetic fields are 90 degrees to each other
How would you describe photons in terms of the quantum theory?
-Particle-like unit, but travels as a wave
What is fluorescence
-Electrons moving from higher to lower energy in the valence shell and releases energy; happens when enough energy is released from electron that it CREATES a photon exciting atom
What is electron excitation?
electrons in shell get energy to jump up to a higher E level
What happens as you increase kVp in regards to dose and Energy
why?
-As you increase kVp, you increase dose because you are making more low energy photons. The higher E kVp are more penetrating and don’t contribute most to dose.
What is the majority of the x ray beam made of?
high or low energy?
Low energy photons
When you pick a kVp, what is the average energy of the photons?
1/3 to 1/2 of what you chose
What is the max energy of a photon determined by?
with Bremms radiation
kVp
What type of energy tends to have more wave-like properties?
Lower energy EMR
What type of energy tends to have more particle properties?
high or low?
Higher energy EMR
Define quantum
The smallest unit of something
What speed does EMR travel at in a vaccum?
EMR travels at the speed of light in a vaccum regardless of the energy
