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Pencil Beam example, penumbra modeling
15
r
z
gap
Collimator plane
Patient
z
θ
gap
At calculation points well inside field limits,
PB width set to zero at patient level not to
wash out effects from heterogeneities
Utrecht 2016
r
gap
z
gap
Collimator plane
Patient
r
r
proj
gap
2
2
+
proj
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