ESTRO course Dose Modelling and Verification 2017

12

Flattening of the direct photon beam

The conical flattening filter absorbs 50-90% of the direct photons on the central axis. In addition, it works as a scatter source located 7-15 cm downstream from the target, adding 5-10% at isocenter.

e -

Lateral fluence distribution

h 

Before ff

After ff

Steel, Brass, Lead...

T Knöös

Warsaw 2017