Advanced Physics for Brachytherapy 2018

Objectives & Objective Functions (several: GTVs, OARs, NT,..) Inverse Optimisation and Planning

Create a single Objective Function via weighted Aggregation

The M objective functions f m

are combined into a single objective function f , by

using a weighted sum (aggregation) of all objectives:

1

=

෍ =1

Θ −

−



M

      ) , , ( w t

1 =  = m

r f fw f m m =

1

=

෍ =1

Θ −

−

w

m : the relative Importance Factors ( IFs ) for the individual Objective Functions f m or Penalties for the penalisation of the violation of the individual objectives .

These are considered as a measure of the significance of each of the objectives/objective functions in the optimisation process.

The optimisation process equals then the minimisation of the Aggregated Objective Function f .