Dose Course 2018_Flipping book

Dose per MU formalisms: factor-based dose calculations

(

)

(

)  

; ,

ref d SSD dsD ref

; , SSD d cD

+

 )(

d

ref

ref

s factor

=

M

M

dosimetric quantities to account for all differences from the reference irradiation geometry in terms of:

• distance from source ( ~ inverse square law) • field size and depth ( ~ scatter dose in medium)

• modulation ( ~ beam intensity) • attenuators in the beam path

• position off axis • heterogeneities