Safety in MR-enhanced daily adaptive SBRT Radiotherapy using a conventional C-arm linear accelerator - An FMEA approach

Sep 29, 2026

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MR-guided online adaptive radiotherapy uses MR soft-tissue contrast for real-time adaptation, but adoption is limited by the cost and infrastructure demands of integrated MR-Linac systems. To expand access, a workflow for MR-enhanced daily adaptive SBRT (MEDAS) was developed on a conventional C-arm linac using a dedicated MR simulator and a patient transfer shuttle. A failure mode and effects analysis (FMEA) quantified risks across process steps and guided mitigation measures.

LanguageEnglish

CategoryHealthcare

FormatPDF

Pages5

Reading Time13 min

AccessFree to download

Background and Purpose

Materials and Methods

Results

Conclusion

Introduction

MR-guided online adaptive radiotherapy and MR-Linac constraints

Decoupled MEDAS on a conventional C-arm linac

Need for FMEA risk assessment

Zeitschrift für Medizinische Physik 35 (2025) 423–427 Contents lists available at ScienceDirect Zeitschrift für Medizinische Physik journal [homepage:](homepage: www.elsevier.com/locate/zemedi)[ www.elsevier.com/locate/zemedi](homepage: www.elsevier.com/locate/zemedi) | Safety in MR-enhanced daily adaptive SBRT Radiotherapy using a conventional C-arm linear accelerator: An FMEA approach
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Lotte Wilke , Sebastian M. Christ , Riccardo Dal Bello , Elizabeth Denney , Silvia Fabiano , Hubert S. Gabry´s , Klara Kefer , Michael Mayinger , Ina Nilo , Sophie Perryck , Jens von der Grün , Matthias Guckenberger , Stephanie Tanadini-Lang
Department of Radiation Oncology, University Hospital Zurich, Switzerland | | | | --- | --- | --- | | A R T I C L E I N F O | | A B S T R A C T | | Keywords:
SBRT
Online-adaptive RT MR guided RT Daily adaptive RT | | Background and Purpose: MR-guided adaptive Radiotherapy has the potential to compensate for interfractional changes in patient anatomy. Modern hybrid devices, which combine MR and linear accelerator technologies, have been clinically implemented but their costs may prevent broad adoption. To accelerate the adoption of MRguided adaptive radiotherapy, we developed a workflow for MR-enhanced daily adaptive Radiotherapy on a Carm linac using a dedicated MR simulator and a patient transfer shuttle system. A failure mode and effects analysis (FMEA) was performed to identify possible risks in this newly developed workflow.
Materials and Methods: A workflow for MR-enhanced daily adaptive SBRT (MEDAS) on a Varian Truebeam linac was developed using a stand-alone 1.5T MR-simulator and patient transfer using a shuttle system. The different process steps were conceptualized in a multidisciplinary team and an FMEA of the different process steps was performed as well as measures for mitigation of possible risks were discussed.
Results: The FMEA identified 23 failure modes across eight process steps, with the majority occurring during base plan preparation and adaptive planning. Seventeen (74%) failure modes were classified as low risk, while six (26%) were assessed as medium risk. No high-risk failure modes were identified. Risk mitigation measures, including workflow automation and checklist enhancements, successfully reduced all failure modes to low risk while not introducing new risks
Conclusion: We developed a workflow for MEDAS on a conventional C-Arm linac. In this process, an FMEA was performed in a multidisciplinary team. The FMEA identified and addressed six medium-risk failure modes within the MEDAS workflow. Through further automation and adaption of existing checklists, the occurrence- and discover probability was successfully reduced, such that these failure modes are decreased to a low risk. | Introduction Magnetic resonance (MR)-guided online adaptive radiotherapy (MRgART) marks a significant advancement in radiation oncology, leveraging the superior soft tissue contrast of MR imaging to achieve precise tumor targeting [1].This approach allows real-time treatment adaptation, enhancing tumor dose escalation while minimizing exposure to healthy tissues, particularly in anatomically complex regions [2,3]. Traditionally, MRgART has been associated with integrated hybrid systems combining an MR scanner and linear accelerator (MR-Linac) into a single unit [4,5]. While these systems offer seamless integration, they come with significant challenges, including high costs, complex infrastructure requirements, and limited availability [6]. In contrast, aworkflow employing two decoupled systems—a standalone MR scanner for imaging and a conventional C-arm linac for treatment—presents an alternative that is less resource-intensive and more cost-effective. This MR-enhanced daily adaptive SBRT (MEDAS) approach increases accessibility, enabling more healthcare facilities to offer advanced MRgART and thereby enlarge the patient population that can benefit from these i

FAQs

What problem does the MEDAS workflow aim to solve?

It aims to make MR-guided online adaptive radiotherapy more accessible by enabling MR-enhanced daily adaptive SBRT on a conventional C-arm linac, avoiding the high costs and infrastructure requirements of MR-Linac systems.

How was risk assessed in the study?

A failure mode and effects analysis (FMEA) was performed to identify possible failure modes in the newly developed MR-enhanced daily adaptive SBRT workflow and to evaluate mitigation strategies.

What were the main FMEA results and risk outcomes?

The FMEA identified 23 failure modes across eight process steps, with 17 classified as low risk and 6 as medium risk. After mitigation measures such as workflow automation and checklist enhancements, all failure modes were reduced to low risk without introducing new risks.

Sep 29, 2026

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