Adaptive treatments are a must for protons

Adaptive treatments are increasingly applied in photon radiotherapy, with images acquired during the treatment cycle used to evaluate and replan the delivered dose distributions and compensate for any anatomical changes. The same cannot be said for proton therapy, however. Instead, proton treatments tend to focus on sites where anatomical changes are not expected, such as within the skull, or are designed with beam paths tailored to avoid regions where changes are likely.