[Start of activity with the MRIdian® system: The first 200 patients treated at the Institut Paoli-Calmettes]

Bull Cancer. 2021 Nov;108(11):1010-1018. doi: 10.1016/j.bulcan.2021.05.013. Epub 2021 Oct 6.
[Article in French]


Introduction: Several centers have recently been equipped with MRI-guided radiotherapy systems, including the Paoli-Calmettes Institute which was the first French center to start this activity. We report in this article our early experience.

Methods: Data related to patients treated on the MRIdian® (Viewray®) were prospectively collected. Procedures concerning the implementation of the system and internal organizational issues were summarized.

Results: Between February 2019 and March 2020, 201 patients were treated: 40% of treatments were normofractionated (n=70) and 60% used hypofractionation (n=105). The reported monthly occupancy rate at one, six and twelve months was 30%, 62%, and 90%. The distribution of normofractionated treatments was dominated by prostatic (29%) and pancreatic (26%) cancers, followed by abdomino-pelvic irradiations for gynecological cancers (12%) or lymph node diseases (12%) and boosts for rectal or vaginal cancers (11%). Regarding treatments with moderate hypofractionation (dose by fraction between 3 and 5Gy), they corresponded mainly to integrated boost for abdomino-pelvic lymph nodes (38%), while the stereotaxic treatments primarily concerned hepatic lesions (15%), bones (30%).

Discussion: The MRIdian® was initially used widely in our service corresponding to a learning curve for MRI guidance. This new tool for image-guided radiotherapy helped us to secure our practice providing solutions for both inter and intra-fraction movements making it possible to reduce the additional margin in order to better protect the organs at risk. The main technical difference with conventional accelerators is the possibility of performing adaptive radiotherapy in real time, the start of which was more gradual.

Keywords: Clinical experience; Démarrage d’activité; Expérience clinique; MR-guided radiotherapy; Radiothérapie guidée par IRM; Start of activity.

MeSH terms

  • Cancer Care Facilities
  • Dose Fractionation, Radiation
  • Female
  • France
  • Humans
  • Magnetic Resonance Imaging, Interventional* / instrumentation
  • Magnetic Resonance Imaging, Interventional* / methods
  • Magnetic Resonance Imaging, Interventional* / statistics & numerical data
  • Male
  • Neoplasms / radiotherapy*
  • Organs at Risk
  • Prospective Studies
  • Radiation Dose Hypofractionation
  • Radiation Injuries / prevention & control
  • Radiotherapy, Image-Guided* / instrumentation
  • Radiotherapy, Image-Guided* / methods
  • Radiotherapy, Image-Guided* / statistics & numerical data
  • Time Factors
  • Workflow