Dose Course 2018_Flipping book

concepts:

Pencil kernel

Dose calculation

View the incident photon fluence as composed (i.e. a sum) of pencil beams Summing pencil kernels in the same way gives dose

“Pencil” beam of photons

“pencil” beam = point monodirectional beam

p

Water phantom

(

)

(

)

(

)

 

, x x y y z x y − − , d d    

, D x y z ,

, x y

=









Field

Pencil kernel = dose pattern caused by a pencil beam (per amount of radiation)

Energy fluence 