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Contribution Details

Type Journal Article
Scope Discipline-based scholarship
Title Synthetic computed tomography for low-field magnetic resonance-guided radiotherapy in the abdomen
Organization Unit
Authors
  • Mariia Lapaeva
  • Agustina La Greca Saint-Esteven
  • Philipp Wallimann
  • Manuel Günther
  • Ender Konukoglu
  • Nicolaus Andratschke
  • Matthias Guckenberger
  • Stephanie Tanadini-Lang
  • Riccardo Dal Bello
Item Subtype Original Work
Refereed Yes
Status Published in final form
Language
  • English
Journal Title Physics and imaging in radiation oncology
Publisher Elsevier
Geographical Reach international
ISSN 2405-6316
Volume 24
Page Range 173 - 179
Date 2022
Abstract Text Background and purpose The requirement of computed tomography (CT) for radiotherapy planning may be bypassed by synthetic CT (sCT) generated from magnetic resonance (MR), which has recently led to the clinical introduction of MR-only radiotherapy for specific sites. Further developments are required for abdominal sCT, mostly due to the presence of mobile air pockets affecting the dose calculation. In this study we aimed to overcome this limitation for abdominal sCT at a low field (0.35 T) hybrid MR-Linac. Materials and methods A retrospective analysis was conducted enrolling 168 patients corresponding to 215 MR-CT pairs. After the exclusion criteria, 152 volumetric images were used to train the cycle-consistent generative adversarial network (CycleGAN) and 34 to test the sCT. Image similarity metrics and dose recalculation analysis were performed. Results The generated sCT faithfully reproduced the original CT and the location of the air pockets agreed with the MR scan. The dose calculation did not require manual bulk density overrides and the mean deviations of the dose-volume histogram dosimetric points were within 1 % of the CT, without any outlier above 2 %. The mean gamma passing rates were above 99 % for the 2 %/ 2 mm analysis and no cases below 95 % were observed. Conclusions This study presented the implementation of CycleGAN to perform sCT generation in the abdominal region for a low field hybrid MR-Linac. The sCT was shown to correctly allocate the electron density for the mobile air pockets and the dosimetric analysis demonstrated the potential for future implementation of MR-only radiotherapy in the abdomen.
Free access at PubMed ID
Official URL https://doi.org/10.1016/j.phro.2022.11.011
Digital Object Identifier 10.1016/j.phro.2022.11.011
PubMed ID 36478992
Other Identification Number merlin-id:23000
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Keywords Radiology, Nuclear Medicine and imaging, Radiation