Standardizing MRI-only radiotherapy commissioning: Benchmark dataset and acceptance levels from the MESCAL initiative.
Authors
Affiliations (21)
Affiliations (21)
- Mater Olbia Hospital, Unità Operativa di Fisica Medica e Radioprotezione, Olbia, Italy.
- Department of Radiation Oncology, University Medical Center Utrecht, Utrecht, the Netherlands; Computational Imaging Group for MR Diagnostics & Therapy, University Medical Center Utrecht, Utrecht, the Netherlands.
- OncoRay - National Center for Radiation Research in Oncology, Faculty of Medicine and University Hospital Carl Gustav Carus, TUD Dresden University of Technology, Helmholtz-Zentrum Dresden-Rossendorf, Dresden, Germany; Department of Radiotherapy and Radiation Oncology, Faculty of Medicine and University Hospital Carl Gustav Carus, TUD Dresden University of Technology, Dresden, Germany.
- Univ Rennes, CHU Rennes, CLCC Eugène Marquis, Inserm, LTSI - UMR 1099, F-35000 Rennes, France.
- Université Bourgogne Europe, Centre Georges-François Leclerc, Unicancer, Department of Medical Physics, 21000 Dijon, France.
- Department of Radiation Oncology, Amsterdam UMC, Amsterdam, The Netherlands, and Cancer Center Amsterdam, Amsterdam, the Netherlands.
- Department of Radiation Oncology, University Hospital Zurich and University of Zurich, Zurich, Switzerland.
- Institut de Cancerologie de l'Ouest, Department of Medical Physics, Angers, France. Electronic address: [email protected].
- Department of Radiation Oncology, LMU University Hospital, LMU Munich, Munich, Germany.
- Medical Physics Unit, Imaging Institute of Southern Switzerland, Ente Ospedaliero Cantonale, Bellinzona, Switzerland.
- Ecomedica-Poliambulatorio, Reparto di Radioterapia, Empoli (FI), Italy.
- Department of Radiation Oncology, Gustave Roussy Cancer Campus, Villejuif, France.
- Department of Radiation Oncology, University Medical Center Utrecht, Utrecht, the Netherlands.
- Department of Medical Physics, Hospital de la Santa Creu i Sant Pau, Barcelona, Spain.
- OncoRay - National Center for Radiation Research in Oncology, Faculty of Medicine and University Hospital Carl Gustav Carus, TUD Dresden University of Technology, Helmholtz-Zentrum Dresden-Rossendorf, Dresden, Germany; Czech Technical University in Prague, Prague, Czech Republic.
- Department of Nuclear Medicine and Medical Physics, Karolinska University Hospital, Stockholm, Sweden.
- Université Toulouse, Oncopole Claudius Regaud, IUCT-Oncopole, Medical Physics Department, Toulouse, France; Centre de Recherches en Cancérologie de Toulouse, UMR1037 INSERM-Université Toulouse 3-ERL5294 CNRS, Oncopole F-31037 Toulouse, France.
- Northern Centre for Cancer Care, The Newcastle upon Tyne Hospitals NHS Foundation Trust, United Kingdom.
- Northwestern University Feinberg School of Medicine, Chicago, IL 60611, USA.
- Fondazione Policlinico Universitario Agostino Gemelli, IRCCS, Department of Diagnostic Imaging, Oncological Radiotherapy and Hematology, Rome, Italy.
- Abano Terme Hospital, Dipartimento di Radioterapia, Padova, Italy.
Abstract
Magnetic Resonance Imaging (MRI)-only, radiotherapy (RT) is increasingly adopted, but still lacks standardized commissioning procedures. This variability limits consistent clinical implementation: the Multicenter Evaluation of commercial Synthetic-Computed tomography ALgorithms (MESCAL) project aims to establish a benchmark dataset, provide commissioning guidelines, and define tolerance levels to support safe and reproducible MRI-only photon-beam RT adoption. Data from 32 patients (16 brain, 16 pelvis) were retrospectively collected from two centers. Four sCT solutions licensed for clinical use were evaluated: MRI Planner (Spectronic), SyngoAI (Siemens), MR Box (Therapanacea), and MRCAT (Philips). For each patient, multiple sCTs were generated and compared with the planning CT. Image quality was assessed using mean absolute error (MAE) and three additional indicators. Dose accuracy was evaluated by recalculating treatment plans on sCTs and performing dose-volume histogram (DVH) analysis. Position-verification accuracy was quantified by comparing CBCT-to-sCT versus CBCT-to-CT registrations. Plans meeting acceptability criteria (DVH differences < 2%, gamma-passing rate 95% at 2%/2 mm) were used to derive tolerance intervals. Three to four sCTs were generated per case. Brain cases showed higher inter-software variability than pelvic cases, particularly in MAE within body (pelvis: 30-70 HU; brain: 40-130 HU). DVH differences remained within 3% (pelvis) and 4% (brain). Position-verification accuracy was higher in the brain (89% within 1 mm/1°) than in the pelvis (74%). Acceptability criteria were met by 37/43 pelvic and 30/39 brain plans: tolerance values were derived from these cases. MESCAL provides a commissioning framework, benchmark dataset, and tolerance levels to guide local sCT commissioning and promote standardized MRI-only photon-beam RT implementation.