NCT07083648

Magnetic Resonance Imaging-guided Online Adaptive Radiotherapy of Pelvic Lymph Node Metastases

Magnetic Resonance Imaging-guided Online Adaptive Radiotherapy Using a Dedicated MR-simulator and a Cone Beam CT Based Treatment Delivery for Stereotactic Body Radiation Therapy of Pelvic Lymph Node Metastases (MACULA-Trial)

• Status: Active Not Recruiting
• Phase: N/A
• Study type: Interventional
• Enrollment: 20 (estimated)
• Sponsor: University of Zurich · Academic / Other
• Sex: All
• Age: 18 Years
• Healthy volunteers: Not accepted

Summary

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.

Detailed description

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.

Conditions

• Pelvic and Para-aortic Lymph Node Metastases

Interventions

Type	Name	Description
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.

Timeline

• Start date: 2025-07-16
• Primary completion: 2027-06-01
• Completion: 2028-07-01
• First posted: 2025-07-24
• Last updated: 2026-01-28

Locations

1 site across 1 country: Switzerland