845 / 1542
2 4 6 8 10 12
0
Relative effective dose / %
Depth in water / cm
20
40
60
80
100
Photons
(15 MV X-rays)
Protons
90
120 MeV
20
40
60
80
100
2 4 6 8 10 12
0
Depth in water (cm)
Relative effective dose / %
Protons: basic physics
Depth in water (cm)
Relative dose
20 MeV electrons
8 MV photons
200 MeV
protons