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Impact of increasing energy on interactions
•
The nature of the x-ray image obtained is related to the type of
interaction which occurs.
•
At X-ray energies in the kilovoltage (kV) range the interaction is
predominately via the
photoelectric effect.
As the X-ray energy
increases to megavoltage (MV) levels the most likely interaction is via
the
Compton interaction.
•
Results in poorer soft tissue contrast with MV imaging
0.00
0.20
0.40
0.60
0.80
1.00
Compton
1 MeV
10MeV
100keV
10keV
1keV
Photoelectric
Compton