Validation of a robust strategy for proton spot scanning for oesophageal cancer in the presence of anatomical changes.

Highlights • Posterior beam proton spot scanning secures a high robustness towards anatomical changes. • Robust optimization in combination with full PTV coverage yields the highest robustness. • Posterior beam proton spot scanning maintains significant sparring of dose to normal tissue compared to IMRT. Abstract SFUD strategies with one or two posterior proton beams and three target coverage strategies are compared with IMRT and tested for robustness towards anatomical changes by recalculation on surveillance CTs during treatment. We find posterior beam SFUD combining PTV coverage with robust optimization increases robustness towards anatomical changes compared to IMRT. [ABSTRACT FROM AUTHOR]