Lena Nenoff1, Cássia O Ribeiro2, Michael Matter3, Luana Hafner3, Mirjana Josipovic4, Johannes A Langendijk2, Gitte F Persson5, Marc Walser6, Damien Charles Weber7, Antony John Lomax3, Antje-Christin Knopf8, Francesca Albertini6, Ye Zhang6. 1. Paul Scherrer Institute, Center for Proton Therapy, Switzerland; Department of Physics, ETH Zurich, Switzerland. Electronic address: lena.nenoff@psi.ch. 2. Department of Radiation Oncology, University Medical Center Groningen, University of Groningen, The Netherlands. 3. Paul Scherrer Institute, Center for Proton Therapy, Switzerland; Department of Physics, ETH Zurich, Switzerland. 4. Department of Oncology, Rigshospitalet Copenhagen University Hospital, Denmark. 5. Department of Oncology, Rigshospitalet Copenhagen University Hospital, Denmark; Department of Oncology, Herlev-Gentofte Hospital Copenhagen University Hospital, Denmark; Department of Clinical Medicine, Faculty of Medical Sciences, University of Copenhagen, Denmark. 6. Paul Scherrer Institute, Center for Proton Therapy, Switzerland. 7. Paul Scherrer Institute, Center for Proton Therapy, Switzerland; Department of Radiation Oncology, University Hospital Zurich, Switzerland; Department of Radiation Oncology, University Hospital Bern, Switzerland. 8. Department of Radiation Oncology, University Medical Center Groningen, University of Groningen, The Netherlands; Division for Medical Radiation Physics, Carl von Ossietzky University Oldenburg, Germany.
Abstract
BACKGROUND AND PURPOSE: Non-small cell lung cancer (NSCLC) patients show typically large anatomical changes during treatment, making recalculation or adaption necessary. For report and review, the applied treatment dose can be accumulated on the reference planning CT using deformable image registration (DIR). We investigated the dosimetric impact of using six different clinically available DIR algorithms for dose accumulation in presence of inter-fractional anatomy variations. MATERIALS AND METHODS: For seven NSCLC patients, proton treatment plans with 66 Gy-RBE to the planning target volume (PTV) were optimised. Nine repeated CTs were registered to the planning CT using six DIR algorithms each. All CTs were acquired in visually guided deep-inspiration breath-hold. The plans were recalculated on the repeated CTs and warped back to the planning CT using the corresponding DIRs. Fraction doses warped with the same DIR were summed up to six different accumulated dose distributions per patient, and compared to the initial dose. RESULTS: The PTV-V95 of accumulated doses decreased by 16% on average over all patients, with variations due to DIR selection of 8.7%. A separation of the dose effects caused by anatomical changes and DIR uncertainty showed a good agreement between the dose degradation caused by anatomical changes and the dose predicted from the average of all DIRs (differences of only 1.6%). CONCLUSION: The dose degradation caused by anatomical changes was more pronounced than the uncertainty of employing different DIRs for dose accumulation, with averaged results from several DIRs providing a good representation of dose degradation caused by anatomy. However, accumulated dose variations between DIRs can be substantial, leading to an additional dose uncertainty.
BACKGROUND AND PURPOSE:Non-small cell lung cancer (NSCLC) patients show typically large anatomical changes during treatment, making recalculation or adaption necessary. For report and review, the applied treatment dose can be accumulated on the reference planning CT using deformable image registration (DIR). We investigated the dosimetric impact of using six different clinically available DIR algorithms for dose accumulation in presence of inter-fractional anatomy variations. MATERIALS AND METHODS: For seven NSCLCpatients, proton treatment plans with 66 Gy-RBE to the planning target volume (PTV) were optimised. Nine repeated CTs were registered to the planning CT using six DIR algorithms each. All CTs were acquired in visually guided deep-inspiration breath-hold. The plans were recalculated on the repeated CTs and warped back to the planning CT using the corresponding DIRs. Fraction doses warped with the same DIR were summed up to six different accumulated dose distributions per patient, and compared to the initial dose. RESULTS: The PTV-V95 of accumulated doses decreased by 16% on average over all patients, with variations due to DIR selection of 8.7%. A separation of the dose effects caused by anatomical changes and DIR uncertainty showed a good agreement between the dose degradation caused by anatomical changes and the dose predicted from the average of all DIRs (differences of only 1.6%). CONCLUSION: The dose degradation caused by anatomical changes was more pronounced than the uncertainty of employing different DIRs for dose accumulation, with averaged results from several DIRs providing a good representation of dose degradation caused by anatomy. However, accumulated dose variations between DIRs can be substantial, leading to an additional dose uncertainty.
Authors: Alisha Duetschler; Grzegorz Bauman; Oliver Bieri; Philippe C Cattin; Stefanie Ehrbar; Georg Engin-Deniz; Alina Giger; Mirjana Josipovic; Christoph Jud; Miriam Krieger; Damien Nguyen; Gitte F Persson; Rares Salomir; Damien C Weber; Antony J Lomax; Ye Zhang Journal: Med Phys Date: 2022-03-17 Impact factor: 4.506
Authors: Florian Amstutz; Silvia Fabiano; Louise Marc; Damien Charles Weber; Antony John Lomax; Jan Unkelbach; Ye Zhang Journal: Med Phys Date: 2022-05-25 Impact factor: 4.506
Authors: Harald Paganetti; Chris Beltran; Stefan Both; Lei Dong; Jacob Flanz; Keith Furutani; Clemens Grassberger; David R Grosshans; Antje-Christin Knopf; Johannes A Langendijk; Hakan Nystrom; Katia Parodi; Bas W Raaymakers; Christian Richter; Gabriel O Sawakuchi; Marco Schippers; Simona F Shaitelman; B K Kevin Teo; Jan Unkelbach; Patrick Wohlfahrt; Tony Lomax Journal: Phys Med Biol Date: 2021-02-26 Impact factor: 4.174