ESTRO course Dose Modelling and Verification 2017

16

Pencil Beam example, penumbra modeling

Collimator plane

z

gap

At calculation points well inside field limits, PB width set to zero at patient level not to wash out effects from heterogeneities

Patient

 gap

z

r

proj

Collimator plane

r

z

gap

gap

At calculation points in penumbra region, PB width set to zero at collimator level to correctly model penumbra width including effects of in air scattering

Patient

2

r 2 

r

proj

gap

Warsaw 2017