Interactions Of X-Rays With Matter

Question 1

What are the 4 possible fates of individual x-ray photons

Answer 1

1. Penetration (Transmitted)
2. Absorption (Photoelectric Interaction)
3. Scattered with energy loss (Compton Interaction)
4. Scattered without energy loss (Elastic Interaction)

Question 2

Penetration

Answer 2

The photon penetrates the matter without interacting with it

Question 3

Absorption

Answer 3

The photon interacts with the matter and is completely absorbed by depositing all of its energy into the matter

Question 4

Scattered

Answer 4

The photon interacts with the matter and is scattered from its original direction, depositing either PART or NONE of its energy into the matter

Question 5

Attenuation

Answer 5

The attempt to numerically describe the collective fates of a large number of photons as they interact with matter

Two main components:
1. Scatter
2. Absorption

Question 6

What are the 2 attenuation processes important for diagnostic imaging

Answer 6

1. Compton or modified scatter (energy loss)
2. Photoelectric absorption

Question 7

Describe the angles of Compton scatter

Answer 7

Back scatter
Side scatter
Forward scatter

Question 8

Describe continuous radiation

Answer 8

Continuous X-ray spectra
Produced by braking radiation
E- attracted towards nucleus & deviated
Gives off IR photon

Question 9

Describe characteristic radiation

Answer 9

Line spectra
E- accelerated towards target metal
Hits an electron in atoms shell causing it to be ejected
E- from higher energy level gives off photon & drops down an energy level to fill space in shell

Question 10

Compton scatter

Answer 10

X-ray photon interacts with an outer shell electron & causes the X-ray photon to change direction

Question 11

Photoelectric absorption

Answer 11

X-ray photon gives up all energy to eject an electron from its shell

Question 12

Thermionic emission

Answer 12

Putting enough energy into the filament to liberate the electron