A case-control study of linear energy transfer and relative biological effectiveness related to symptomatic brainstem toxicity following pediatric proton therapy
Lars Fredrik Fjæra, Daniel J. Indelicato, Andreas H. Handeland, Kristian S. Ytre-Hauge, Yasmin Lassen–Ramshad, L.P. Muren, Camilla H. Stokkevåg
Abstract
BACKGROUND AND PURPOSE: ) is used clinically in proton therapy even though the RBE varies with properties such as dose level and linear energy transfer (LET). We therefore investigated if symptomatic brainstem toxicity in pediatric brain tumor patients treated with proton therapy could be associated with a variable LET and RBE. MATERIALS AND METHODS: ) and variable RBE-weighted dose from two RBE models were analyzed in the high-dose region. RESULTS: in the brainstem for cases compared to controls (P =.08), while the difference in the median variable RBE-weighted dose for the same structure was only 2% (P =.6). CONCLUSION: metrics for this patient cohort. While case-control differences were minor, an association with the observed symptomatic brainstem toxicity cannot be ruled out.