TY - JOUR
T1 - Comparison of Library of Plans with two daily adaptive strategies for whole bladder radiotherapy
AU - den Boer, Duncan
AU - den Hartogh, Mariska D
AU - Kotte, Alexis N T J
AU - van der Voort van Zyp, Jochem R N
AU - Noteboom, Juus L
AU - Bol, Gijsbert H
AU - Willigenburg, Thomas
AU - Werensteijn-Honingh, Anita M
AU - Jürgenliemk-Schulz, Ina M
AU - van Lier, Astrid L H M W
AU - Kroon, Petra S
N1 - Funding Information: The overarching University Medical Center Utrecht MR-linac scientific project, including employment of one of the authors, has been partly funded by Elekta AB (Stockholm, Sweden). Elekta did not have any part in the design, execution or analysis of this study. The authors declared that there is no other conflict of interest. Publisher Copyright: © 2021 The Authors
PY - 2021/10
Y1 - 2021/10
N2 - Background and purpose: Whole bladder radiotherapy is challenging due to inter- and intrafraction size and shape changes. To account for these changes, currently a Library of Plans (LoP) technique is often applied, but daily adaptive radiotherapy is also increasingly becoming available. The aim of this study was to compare LoP with two magnetic resonance imaging guided radiotherapy (MRgRT) strategies by comparing target coverage and volume of healthy tissue inside the planning target volume (PTV) for whole bladder treatments.Methods and materials: Data from 25 MRgRT lymph node oligometastases treatments (125 fractions) were used, with three MRI scans acquired at each fraction at 0, 15 and 30 min. Bladders were delineated and used to evaluate three strategies: 1) LoP with two plans for a 15 min fraction, 2) MRgRT15min for a 15 min fraction and 3) MRgRT30min for a 30 min fraction. The volumes of healthy tissue inside and bladder outside the PTV were analyzed on the simulated post-treatment images.Results: MRgRT30min had 120% and 121% more healthy tissue inside the PTV than LoP and MRgRT15min. For LoP slightly more target outside the PTV was found than for MRgRT30min and MRgRT15min, with median 0% (range 0-23%) compared to 0% (0-20%) and 0% (0-10%), respectively.Conclusions: Taking into account both target coverage and volume of healthy tissue inside the PTV, MRgRT15min performed better than LoP and MRgRT30min for whole bladder treatments. A 15 min daily adaptive radiotherapy workflow is needed to potentially benefit from replanning compared to LoP.
AB - Background and purpose: Whole bladder radiotherapy is challenging due to inter- and intrafraction size and shape changes. To account for these changes, currently a Library of Plans (LoP) technique is often applied, but daily adaptive radiotherapy is also increasingly becoming available. The aim of this study was to compare LoP with two magnetic resonance imaging guided radiotherapy (MRgRT) strategies by comparing target coverage and volume of healthy tissue inside the planning target volume (PTV) for whole bladder treatments.Methods and materials: Data from 25 MRgRT lymph node oligometastases treatments (125 fractions) were used, with three MRI scans acquired at each fraction at 0, 15 and 30 min. Bladders were delineated and used to evaluate three strategies: 1) LoP with two plans for a 15 min fraction, 2) MRgRT15min for a 15 min fraction and 3) MRgRT30min for a 30 min fraction. The volumes of healthy tissue inside and bladder outside the PTV were analyzed on the simulated post-treatment images.Results: MRgRT30min had 120% and 121% more healthy tissue inside the PTV than LoP and MRgRT15min. For LoP slightly more target outside the PTV was found than for MRgRT30min and MRgRT15min, with median 0% (range 0-23%) compared to 0% (0-20%) and 0% (0-10%), respectively.Conclusions: Taking into account both target coverage and volume of healthy tissue inside the PTV, MRgRT15min performed better than LoP and MRgRT30min for whole bladder treatments. A 15 min daily adaptive radiotherapy workflow is needed to potentially benefit from replanning compared to LoP.
KW - Bladder cancer
KW - Daily online adaptive radiotherapy
KW - Library of Plans
KW - MR-guided radiotherapy
UR - http://www.scopus.com/inward/record.url?scp=85119350837&partnerID=8YFLogxK
U2 - https://doi.org/10.1016/j.phro.2021.11.002
DO - https://doi.org/10.1016/j.phro.2021.11.002
M3 - Article
C2 - 34849413
SN - 2405-6316
VL - 20
SP - 82
EP - 87
JO - Physics and Imaging in Radiation Oncology
JF - Physics and Imaging in Radiation Oncology
ER -