ESTRO course Dose Modelling and Verification 2017

Photon beam attenuation



Energy transfer from the photon beam - TERMA to the medium



Or when including ray tracing



Mass-attenuation coefficients are dependent on the medium of where the

energy is removed from the beam



This energy is transferred to photons and electrons which propagates away

from the interaction site



Coefficient can be downloaded for elements and compounds

= ∙ Φ( , ) ∙

= ∙ Φ

( , = 0) ∙

− ∙

∙

April 2017