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How to protect the proximal bronchial tree during stereotactic radiotherapy of ultracentral lung tumors: Lessons from MR-guided treatment

Purpose - To use imaging data from stereotactic MR-guided online adaptive radiotherapy (SMART) of ultracentral lung tumors (ULT) for development of a safe non-adaptive approach towards stereotactic body radiotherapy (SBRT) of ULT. - Patients and Methods - Analysis is based on 19 patients with ULT wh...

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Main Authors: Regnery, Sebastian (Author) , Katsigiannopulos, Efthimios (Author) , Lau, Hoi Hin (Author) , Hoegen-Saßmannshausen, Philipp (Author) , Weykamp, Fabian (Author) , Renkamp, Claudia Katharina (Author) , Rippke, Carolin (Author) , Schlüter, Fabian (Author) , Albert, Sophia (Author) , Meis, Jan (Author) , Kirchner, Marietta (Author) , Balzer, Alexandra (Author) , Andratschke, Nicolaus (Author) , Guckenberger, Matthias (Author) , Debus, Jürgen (Author) , Klüter, Sebastian (Author) , Hörner-Rieber, Juliane (Author)
Format: Article (Journal)
Language:English
Published: March 2025
In: Clinical and translational radiation oncology
Year: 2025, Volume: 51, Pages: 1-6
ISSN:2405-6308
DOI:10.1016/j.ctro.2024.100899
Online Access:Verlag, kostenfrei, Volltext: https://doi.org/10.1016/j.ctro.2024.100899
Verlag, kostenfrei, Volltext: https://www.sciencedirect.com/science/article/pii/S2405630824001769
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Author Notes:Sebastian Regnery, Efthimios Katsigiannopulos, Hin Lau, Philipp Hoegen-Saßmannshausen, Fabian Weykamp, Claudia Katharina Renkamp, Carolin Rippke, Fabian Schlüter, Sophia Albert, Jan Meis, Marietta Kirchner, Alexandra Balzer, Nicolaus Andratschke, Matthias Guckenberger, Jürgen Debus, Sebastian Klüter, Juliane Hörner-Rieber
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Summary:Purpose - To use imaging data from stereotactic MR-guided online adaptive radiotherapy (SMART) of ultracentral lung tumors (ULT) for development of a safe non-adaptive approach towards stereotactic body radiotherapy (SBRT) of ULT. - Patients and Methods - Analysis is based on 19 patients with ULT who received SMART (10 × 5.0-5.5 Gy) on a 0.35 T MR-Linac (MRIdian®) in the prospective MAGELLAN trial. 4D-planning CT data of six patients served to quantify proximal bronchial tree (PBT) breathing motion. Daily fraction MRIs are used to calculate interfractional translations (mediolateral (ML), anterior-posterior (AP), superior-inferior (SI)) and their dosimetric consequences for the PBT. A planning risk volume (PRV) is calculated for an assumed non-adaptive SBRT in deep-inspiration breath hold (DIBH) with surface-guidance (AlignRT®). Finally, non-adaptive volumetric modulated arc (VMAT) SBRT is simulated with and without a PRV for N = 10 patients (10 × 5.5 Gy). - Results - The PBT shows relevant breathing motion, especially in superior-inferior direction (median ML: 2.5 mm, AP: 1.9 mm and SI: 9.2 mm). Furthermore, moderate interfractional translations are observed (mean absolute translation ML: 1.3 mm, AP: 1.3 mm, SI: 1.1 mm), with an estimated 2 mm PRV margin for interfractional changes alone. Simulated non-adaptive SBRT leads to PBT overdoses in 60 % of patients (median overdosed fractions VMAT: 2.5, predicted MR-linac plans 4). Both MR-guided online plan adaptation (SMART) and PRV-based non-adaptive VMAT prevent PBT overdoses, but SMART yields significantly higher planning target volume (PTV) coverage (SMART: median 96 % [IQR 95-96], VMAT: median 89 % [IQR 77-94], p = 0.014). - Conclusions - Both intrafractional breathing motion and interfractional translations may impact doses to the PBT during SBRT of ULT. SMART protects the PBT from overdoses while maintaining high PTV coverage. Non-adaptive SBRT appears safe with advanced breathing motion management and PRV, but yields inferior PTV coverage.
Item Description:Gesehen am 27.11.2025
Online veröffentlicht: 7. Dezember 2024
Physical Description:Online Resource
ISSN:2405-6308
DOI:10.1016/j.ctro.2024.100899

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