During radiotherapy, changes in patient anatomy or positioning can result into differences in dose deposition, which is the main factor influencing tumor control or side-effects. Dose-guided radiation therapy is the systematic evaluation of the dose delivery during treatment for an individual patient with the aim to adapt the treatment if needed. Recalculation of the dose during treatment can be performed using the imaging information during treatment. In a retrospective study the investigators defined quantitative action levels based on dose and volume measures for adaptive radiation therapy in breast cancer patients (Zegers et al. Acta Oncol 2017). The aim of this study is to validate these parameters in a prospective study.
