RBE-weighted doses in target volumes of chordoma and chondrosarcoma patients treated with carbon ion radiotherapy: comparison of local effect models I and IV
Background and purpose - To compare the relative biological effectiveness (RBE)-weighted dose distributions in the target volume of chordoma and chondrosarcoma patients when using two different versions of the local effect model (LEM I vs. IV) under identical conditions. - Materials and methods - Th...
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| Hauptverfasser: | , , |
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| Dokumenttyp: | Article (Journal) |
| Sprache: | Englisch |
| Veröffentlicht: |
12 September 2019
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| In: |
Radiotherapy and oncology
Year: 2019, Jahrgang: 141, Pages: 234-238 |
| ISSN: | 1879-0887 |
| DOI: | 10.1016/j.radonc.2019.08.006 |
| Online-Zugang: | Verlag, Volltext: https://doi.org/10.1016/j.radonc.2019.08.006 Verlag, Volltext: http://www.sciencedirect.com/science/article/pii/S0167814019330452 
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| Verfasserangaben: | Clarissa Gillmann, Oliver Jäkel, Christian P. Karger |
| Zusammenfassung: | Background and purpose - To compare the relative biological effectiveness (RBE)-weighted dose distributions in the target volume of chordoma and chondrosarcoma patients when using two different versions of the local effect model (LEM I vs. IV) under identical conditions. - Materials and methods - The patient collective included 59 patients treated with 20 fractions of carbon ion radiotherapy for chordoma and low-grade chondrosarcoma of the skull base at the Helmholtzzentrum für Schwerionenforschung (GSI) in 2002 and 2003. Prescribed doses to the planning target volume (PTV) were 60 (n=49), 66 (n=2) and 70 (n=8) Gy (RBE). The original treatment plans that were initially biologically optimized with LEM I, were now recalculated using LEM IV based on the absorbed dose distributions. The resulting RBE-weighted dose distributions were quantitatively compared to assess the clinical impact of LEM IV relative to LEM I in the target volume. - Results - LEM IV predicts 20-30Gy (RBE) increased maximum doses as compared to LEM I, while minimum doses are decreased by 2-5Gy (RBE). Population-based mean and median doses deviated by less than 2Gy (RBE) between both models. - Conclusions - LEM I and LEM IV-based RBE-weighted doses in the target volume may be significantly different. Replacing the applied model in patient treatments may therefore lead to local over- or underdosages in the tumor. If LEM IV is to be tested clinically, comparisons of the RBE-weighted dose distributions of both models are required for the individual patients to assess whether the LEM IV-plan would also be acceptable and prescribed dose as well as clinical outcome data have to be carefully reassessed. |
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| Beschreibung: | Gesehen am 15.01.2020 |
| Beschreibung: | Online Resource |
| ISSN: | 1879-0887 |
| DOI: | 10.1016/j.radonc.2019.08.006 |