Physics Bucharest 2017

Impact of increasing energy on interactions

1.00

0.80

Compton

Photoelectric

0.60

0.40

Compton

0.20

0.00

10MeV

1 MeV

1keV

10keV

100keV

• 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