A multi-institutional comparison of retrospective deformable dose accumulation for online adaptive magnetic resonance-guided radiotherapy

Martina Murr; Uffe Bernchou; Edyta Bubula-Rehm; Mark Ruschin; Parisa Sadeghi; Peter Voet; Jeff D Winter; Jinzhong Yang; Eyesha Younus; Cornel Zachiu; Yao Zhao; Hualiang Zhong; Daniela Thorwarth

doi:10.1016/j.phro.2024.100588

A multi-institutional comparison of retrospective deformable dose accumulation for online adaptive magnetic resonance-guided radiotherapy

Phys Imaging Radiat Oncol. 2024 May 17:30:100588. doi: 10.1016/j.phro.2024.100588. eCollection 2024 Apr.

Authors

Martina Murr¹, Uffe Bernchou^{2

3}, Edyta Bubula-Rehm⁴, Mark Ruschin⁵, Parisa Sadeghi⁶, Peter Voet⁴, Jeff D Winter⁶, Jinzhong Yang⁷, Eyesha Younus^{5

8}, Cornel Zachiu⁹, Yao Zhao⁷, Hualiang Zhong¹⁰, Daniela Thorwarth¹

Affiliations

¹ Section for Biomedical Physics, Department of Radiation Oncology, University of Tübingen, Germany.
² Department of Clinical Research, University of Southern Denmark, Odense, Denmark.
³ Laboratory of Radiation Physics, Odense University Hospital, Denmark.
⁴ Elekta AB, Stockholm, Sweden.
⁵ Department of Radiation Oncology, Odette Cancer Centre, Sunnybrook Health Sciences Centre, University of Toronto, Toronto, Ontario, Canada.
⁶ Radiation Medicine Program, Princess Margaret Cancer Centre, University Health Network, Toronto, Ontario, Canada.
⁷ Department of Radiation Physics, the University of Texas MD Anderson Cancer Center, Houston, TX, USA.
⁸ Department of Radiation Oncology, Mayo Clinic, 200 First Street SW, Rochester, MN, 55905, USA.
⁹ University Medical Centre Utrecht, Department of Radiotherapy, 3584 CX Utrecht, the Netherlands.
¹⁰ Department of Radiation Oncology, Medical College of Wisconsin, Milwaukee, WI, USA.

Abstract

Background and purpose: Application of different deformable dose accumulation (DDA) solutions makes institutional comparisons after online-adaptive magnetic resonance-guided radiotherapy (OA-MRgRT) challenging. The aim of this multi-institutional study was to analyze accuracy and agreement of DDA-implementations in OA-MRgRT.

Material and methods: One gold standard (GS) case deformed with a biomechanical-model and five clinical cases consisting of prostate (2x), cervix, liver, and lymph node cancer, treated with OA-MRgRT, were analyzed. Six centers conducted DDA using institutional implementations. Deformable image registration (DIR) and DDA results were compared using the contour metrics Dice Similarity Coefficient (DSC), surface-DSC, Hausdorff-distance (HD95%), and accumulated dose-volume histograms (DVHs) analyzed via intraclass correlation coefficient (ICC) and clinical dosimetric criteria (CDC).

Results: For the GS, median DDA errors ranged from 0.0 to 2.8 Gy across contours and implementations. DIR of clinical cases resulted in DSC > 0.8 for up to 81.3% of contours and a variability of surface-DSC values depending on the implementation. Maximum HD95%=73.3 mm was found for duodenum in the liver case. Although DVH ICC > 0.90 was found after DDA for all but two contours, relevant absolute CDC differences were observed in clinical cases: Prostate I/II showed maximum differences in bladder V28Gy (10.2/7.6%), while for cervix, liver, and lymph node the highest differences were found for rectum D2cm³ (2.8 Gy), duodenum Dmax (7.1 Gy), and rectum D0.5cm³ (4.6 Gy).

Conclusion: Overall, high agreement was found between the different DIR and DDA implementations. Case- and algorithm-dependent differences were observed, leading to potentially clinically relevant results. Larger studies are needed to define future DDA-guidelines.

Keywords: Deformable dose accumulation (DDA); Deformable image registration (DIR); Multi-institutional analysis; Online MR-guided radiotherapy (MRgRT).