Dose Course 2018_Flipping book

Geometric penumbra

The source related geometric penumbra (10-90%) typically has a width of 3-5 mm at isocenter level, but can in more extreme cases extend up to about 10 mm. Particularly important for small beams and IMRT.

d

coll

d

iso

(SAD)

Y d

Isocenter

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Dublin 2018