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Treatment plan robustness
Robustness of a treatment plan is one of the most important criteria in the plan
assessment – complex treatment plans are susceptible to errors
Major uncertainties:
– Ion range
– RBE (fragementation tail of carbon ions)
Possibilities to achieve a good robustness
– Beam through most homogenous tissue (avoid areas with larger movement)
– Avoiding beam angles perpendicular to organ motion
Assessing robustness against set-up errors and patient or organ motion by
simulating these variation and their influence on dose distribution
Opposing field arrangement is very robust with regard to range uncertainties
PTV margins can be optimised in order to maximise the robustness