Fast and accurate deformable contour propagation for intra-fraction adaptive magnetic resonance-guided prostate radiotherapy

• Published in: Physics and imaging in radiation oncology 2022-01, Vol.21, p.62-65
• Main Authors: Willigenburg, Thomas, Zachiu, Cornel, Lagendijk, Jan J.W., van der Voort van Zyp, Jochem R.N., de Boer, Hans C.J., Raaymakers, Bas W.
• Format: Article
• Language: English
• Subjects: Intra-fraction adaptation; MR-guided linear accelerator; MRI-guided radiotherapy; Original; Prostate cancer; Radiotherapy workflow
• ISSN: 2405-6316; 2405-6316
• DOI: 10.1016/j.phro.2022.02.008

•Accurate contours are needed for intra-fraction adaption using contour propagation.•A deformable image registration algorithm (EVolution) was tested for this purpose.•Clinical quality of intra-fraction propagated contours was assessed by 2 physicians.•EVolution provided good results in 10 prostate cancer cases.•This paves the way for adaptive workflows using deformable contour propagation. To facilitate full intra-fraction adaptive MR-guided radiotherapy, accurate contour propagation is needed. We aimed to assess the clinical usability of intra-fraction propagated contours by a deformable image registration algorithm in ten prostate cancer patients. Two observers judged the contours on need for manual adaptation and feasibility of adapting contours within 3 min. CTV and bladder contours needed none or only minor editing in most cases (≥ 97%), whereas rectum contours needed more extensive editing in 12–23%. Nevertheless, adaptation times were < 3 min for ≥ 93% of the cases. This paves the way for exploring adaptive workflows using intra-fraction deformable contour propagation.