Course book Advanced Treatment Planning 2018

Pencil beam kernel

Calculation object approximations

 0

z

The depth ( z ) is generally assumed to be constant within the lateral integration plane during calculation of the scatter dose to a point.

Primary deposition volume

Calculation point

 0

 0

z

z

z

 0

Primary deposition volume

Primary deposition volume

Primary deposition volume

Calculation point

Calculation point

Calculation point

Scatter overestimated

Scatter underestimated

Errors cancel (roughly)