Seed Spots Analysis to Characterize Linear Energy Transfer (LET) Effect in the Adverse Event Regions of Head and Neck Cancer Patients Treated by Intensity Modulated Proton Therapy (IMPT)

Our observations suggested that dose and LET can contribute to AEs in a complicated fashion. Using the intercept-free bivariate linear regression model, we found a LET-enhancing effect for all 6 AEs included in the study, substantiated by the positive slopes of the empirical dose-LET models. The xBD volume constraint of osteoradionecrosis was derived and showed good performance. We believe that both DLVH and seed spot analysis could be powerful tools for patient outcome studies in IMPT.