An interventional study of Magnetic resonance Imaging-guided online adaptive radiotherapy in Pelvic and Para-aortic Lymph Node Metastases, sponsored by University of Zurich. Active, not recruiting at 1 site in Switzerland. Open to participants aged 18 Years and older. Per ClinicalTrials.gov, last updated 2026-05-11.
Sponsored by University of Zurich · Not applicable, Interventional, and Treatment
In this study, the investigators want to investigate whether online-adapted radiotherapy using a special magnetic resonance imaging (MRI) simulator and computed tomography (CT)-guided radiation therapy, is feasible and offers advantages for the treatment of pelvic lymph node metastases.
MR-guided online adaptive radiotherapy has been implemented recently using MR-linac technology, where MR-imaging is combined with linac technology in hybrid systems. These systems offer MR imaging for online adaptive radiotherapy (RT) within the treatment room and with the patient in treatment position. Despite results regarding technical and clinical feasibility being promising, the high costs of MR-linacs systems and the high demands for staffing resources of MR-linacs are limiting a boarder implementation of this technology. At the Department of Radiation Oncology, University Hospital Zurich, MRI-simulations for RT planning using a dedicated scanner have been performed since 2023. The investigators have developed and implemented an MRI-only RT planning workflow followed by RT delivered at a CBCT-guided, conventional linac. The aim to expand the MRI-only workflow to online adaptive RT. This study will investigate the feasibility of MRI-guided, online adaptive SBRT for pelvic and para-aortic lymph node metastases using a dedicated MR simulator and treatment delivery using conventional CBCT-linac technology.
University of Zurich is the lead sponsor of 1,030 studies on the registry; 130 are open to participants now.
Counted across the registry records on this site, refreshed daily.
Exclusion Criteria:
Contraindications for MRI including but not limited to
Radiation: Magnetic resonance Imaging-guided online adaptive radiotherapy
On each day of treatment, a new MRI scan in the treatment position will be acquired using the dedicated MR simulator, co-registered with the original one. The original target and organ at risk (OAR) contours will be propagated to the new image set using rigid and deformable image registration. The contours will be adapted to changes detected with MRI of the day. The original SBRT treatment plan will be adapted to the changed and hence adapted anatomy of targets and OARs by plan optimization. Dose calculation will be performed on the newly generated synthetic CT (preferred) or, if there is a contra-indication for synthetic CT, on the original image.
Rate of successfully delivered fractions
Feasibility is measured as a successful delivery of an MRI-adapted plan using CBCT image-guidance in another room in 90% of the SBRT fractions.
Time frame: during treatment, 1-2 weeks
Average improvement of coverage of planning target volume
Dosimetric advantage is defined as \>5% improvement in coverage of the planning target volume (PTV) or \>5% better sparing of one of the organs at risk (bowel, sigma , rectum, bladder).
Time frame: During treatment, 1-2 weeks
Adverse Events
Common Terminology Criteria for Adverse Events (CTCAE), version 5.0
Time frame: during SBRT, 3 months and 24 months of follow-up
Plan to share: Undecided
No publications or documents are linked to this record.
This study is active, not recruiting, as verified in May 2026. You cannot join it, but the record below documents what was studied.
Get an email when the registry record changes — status, dates, results — or when someone posts here.
Sign in to followQuestions and observations about this study, from anyone following it. Not medical advice, and not a channel to the study team — their contact details are on the registry record.
Sign in to join the discussion. Reading takes no account; posting does. You choose a display name, and a pseudonym is the default.
Nothing here yet. If you are running this trial, taking part in it, or weighing whether to, this is the place to say so.
University of Zurich