Advanced Physics for Brachytherapy 2018

Inverse Optimisation and Planning

“Desired” Dose Distribution Desired Dose Distribution:

Define Dose Window for Target(s), NT & OAR(s)

Objective Functions

Objectives

General Form of an Objective Function and DVH

Low dose Objective for PTV/GTVs D L = D V for V 100%

L

1

=

෍ =1

Θ −

−

H

High dose Objective for PTV/GTVs D H = D V for V 0%

1

=

෍ =1

Θ −

−

Dose window

The Norm Factor p 0 : Volume counting 1 : Linear penalty 2 : Quadratic penalty

Transition Function Θ: (y) =

0, 1,

∀ < 0 ∀ ≥ 0