The impact of anatomical changes during photon or proton based radiation treatment on tumor dose in glioblastoma dose escalation trials

Highlights: • Twenty-four glioblastoma patients received an additional MRI during radiotherapy. • Photon- and proton-based dose escalated treatment plans were simulated. • For 12.5% of the patients the dose coverage and minimum dose decreased dramatically. • No major differences between the photon and proton treatment plans were found. Most dose-escalation trials in glioblastoma patients integrate the escalated dose throughout the standard course by targeting a specific subvolume. We hypothesize that anatomical changes during irradiation may affect the dose coverage of this subvolume for both proton- and photon-based radiotherapy.