MRI QA for RT

Magnetic Resonance Imaging (MRI) is increasingly used in the process of radiation therapy. To date, MRI is used for a number of applications within the radiation therapy workflow. MRI-guided radiation therapy planning is the process of utilizing the superior soft-tissue contrast of MRI for high precision delineation of target and organs at risk. In most cases, the MR images are co-registered to the planning CT, but MR-only based workflows are now also making their way into the clinic for specific indications (e.g. prostate and brain tumours, brachytherapy for cervix and prostate). Furthermore, targeting uncertainties at the dose delivery phase can be reduced in an MR-integrated workflow, in the form of MRI-integrated brachytherapy and external beam radiation therapy. Finally, MRI has been shown to be an excellent imaging modality for treatment response evaluation. Advanced MRI techniques can provide anatomical and functional information, either in a qualitative or quantitative way.

A concern of integrating MRI into radiation therapy planning is the spatial accuracy of these images, as they are affected by magnetic field inhomogeneities, magnetic susceptibility artefacts, chemical shifts and errors in the gradient fields. Since these effects are system and patient dependent, dedicated procedures for quality assurance and control are needed. Other concerns are the various tools for patient positioning and immobilization, which may not be MR conditional or MR safe, and hence could compromise patient safety and image quality.

This subcommittee will develop a practical report as guideline to integrate the use of MRI in a safe and effective way for radiation therapy planning, dose delivery and treatment response evaluation.

The subcommittee officially started on 30 June 2017.

Topics to be covered

  • General background of the principles and pitfalls of MRI
  • Geometric accuracy requirements
  • Methods and tools for periodic QA
  • Recommendations on QA (with frequency and tolerances)

Members of this NCS subcommittee

  • Zdenko van Kesteren (AMC, Amsterdam,Chairman, z.vankesteren-at-amc.uva.nl)
  • Marloes Frantzen-Steneker (NKI-AVL, Amsterdam,Secretary)
  • Rob Tijssen (UMC Utrecht, Utrecht)
  • Arjan Verduin (UMC Utrecht, Utrecht)
  • Aswin Hoffmann (Helmholtz-Zentrum Dresden-Rossendorf, Dresden Universitätsklinikum an der TU Dresden, Dresden, Germany)
  • Mariska de Smet (Instituut Verbeeten, Tilburg)
  • Pieternel van der Tol (HollandPTC, Delft)
  • Ellen Brunenberg (Radboudumc, Nijmegen)
  • Joost Kuijer (VUmc, Amsterdam)
  • Jeroen van de Kamer (NKI-AVL, Amsterdam), representative of the NCS board
  • Steven Petit (Erasmus MC Cancer Institute, Rotterdam)