ESTRO course Dose Modelling and Verification 2017

38

Positioning rounded collimator edges

Important for dose calculations in small fields and IMRT.

Focal point

A-C

B-C is nearly constant (approx. 0.3 mm) for a Varian MLC.

A-B

A: Projected tip

B: Tangent (light field)

C: Half Value Transmission

Boyer and Li [6]

A,BC

CB A

T Knöös

Warsaw 2017