Physics Bucharest 2017

Robust Optimization

Aim Mitigate the influence of uncertainties in IMPT and limit dose degradation due to un-intended range variations

How Include uncertainties in the optimization process

Robust optimization Errors in patient positioning (setup errors) and range errors are explicitly included in plan optimization, optimizing the expected value or worst-case value of the objective function or individual objectives NB the optimization target is the CTV E.g. Worst case scenario – minimizes the penalty of the worst scenario (among a limited number of error scenarios), with no regards to the probabilities of the scenarios. It may result in overlay conservative plans

Price of robustness? OARs dose, but could be better than the PTV approach

Robust evaluation: Incorporate the impact of uncertainties when evaluating an IMPT plan