De Saint-Hubert, MarijkeBoissonnat, GuillaumeSchneider, UweBäumer, ChristianVerbeek, NicoEsser, JohannesWulff, JörgStuckmann, FlorianSuesselbeck, FinjaNabha, RacellDabin, JérémieVasi, FabianoRadonic, StephanRodriguez, MiguelSimon, Anne CatherineJourny, NeigeTimmermann, BeateThierry-Chef, IsabelleBrualla, Lorenzo2024-01-152024-01-152023De Saint-Hubert M, Boissonnat G, Schneider U, Bäumer C, Verbeek N, Esser J, Wulff J, Stuckmann F, Suesselbeck F, Nabha R, Dabin J, Vasi F, Radonic S, Rodriguez M, Simon AC, Journy N, Timmermann B, Thierry-Chef I, Brualla L. Complete patient exposure during paediatric brain cancer treatment for photon and proton therapy techniques including imaging procedures. Front Oncol. 2023 Sep 19;13:1222800. DOI: 10.3389/fonc.2023.12228002234-943Xhttp://hdl.handle.net/10230/58677Background: In radiotherapy, especially when treating children, minimising exposure of healthy tissue can prevent the development of adverse outcomes, including second cancers. In this study we propose a validated Monte Carlo framework to evaluate the complete patient exposure during paediatric brain cancer treatment. Materials and methods: Organ doses were calculated for treatment of a diffuse midline glioma (50.4 Gy with 1.8 Gy per fraction) on a 5-year-old anthropomorphic phantom with 3D-conformal radiotherapy, intensity modulated radiotherapy (IMRT), volumetric modulated arc therapy (VMAT) and intensity modulated pencil beam scanning (PBS) proton therapy. Doses from computed tomography (CT) for planning and on-board imaging for positioning (kV-cone beam CT and X-ray imaging) accounted for the estimate of the exposure of the patient including imaging therapeutic dose. For dose calculations we used validated Monte Carlo-based tools (PRIMO, TOPAS, PENELOPE), while lifetime attributable risk (LAR) was estimated from dose-response relationships for cancer induction, proposed by Schneider et al. Results: Out-of-field organ dose equivalent data of proton therapy are lower, with doses between 0.6 mSv (testes) and 120 mSv (thyroid), when compared to photon therapy revealing the highest out-of-field doses for IMRT ranging between 43 mSv (testes) and 575 mSv (thyroid). Dose delivered by CT ranged between 0.01 mSv (testes) and 72 mSv (scapula) while a single imaging positioning ranged between 2 μSv (testes) and 1.3 mSv (thyroid) for CBCT and 0.03 μSv (testes) and 48 μSv (scapula) for X-ray. Adding imaging dose from CT and daily CBCT to the therapeutic demonstrated an important contribution of imaging to the overall radiation burden in the course of treatment, which is subsequently used to predict the LAR, for selected organs. Conclusion: The complete patient exposure during paediatric brain cancer treatment was estimated by combining the results from different Monte Carlo-based dosimetry tools, showing that proton therapy allows significant reduction of the out-of-field doses and secondary cancer risk in selected organs.application/pdfeng© 2023 De Saint-Hubert, Boissonnat, Schneider, Bäumer, Verbeek, Esser, Wulff, Stuckmann, Suesselbeck, Nabha, Dabin, Vasi, Radonic, Rodriguez, Simon, Journy, Timmermann, Thierry-Chef and Brualla. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) and the copyright owner(s) are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.info:eu-repo/semantics/articlehttp://dx.doi.org/10.3389/fonc.2023.1222800Monte Carlo simulationImaging dosimetryOut-of-field dosimetryPhoton radiotherapyProton therapySecondary cancer riskinfo:eu-repo/semantics/openAccess