1200 / 1542
% dd
100
50
0
depth in phantom (cm)
100 cm SSD
142 cm SSD
10
5
2
8 MV
3% @ 10 cm depth
Comparison of central axis depth doses at two source- surface
distances (Philips SL75/10)
The inverse square law is only “fully compensated at D
max
”
The scatter differ due to different divergence