Lecture – prof. dr. Bas Raaymaker

On Monday June 3 at 14.00 in FMF F1 prof. dr. Bas Raaymaker will have a lecture as part of the Monday physics colloquium entitled: 1.5T Magnetic resonance imaging integrated with a photon therapy system for precise tumour irradiation


Radiotherapy aims to kill tumour cells with ionizing radiation. The challenge is to deliver as much dose to the tumour while minimizing the dose to the surrounding structures. This is done by delivering dose from multiple directions, in daily repeated sessions. The conventional way of mitigating geometric uncertainties during this process is to include a safety margin around the target to guarantee sufficient dose to the tumour. Clearly this comes at the expense of damage to the surrounding structures. Image guided radiotherapy, or more specifically in this talk, magnetic resonance imaging (MRI) guided radiotherapy can improve on the precision of radiotherapy.

We developed a radiotherapy system with integrated 1.5T MRI functionality (MRLinac) for precise image guidance. MR is a basic physics principle that can be exploited for unrivalled soft-tissue contrasts, and with proper image reconstruction techniques also enable tracking of anatomical motion during treatment. One of the open challenges is how to digest the continuously updated  anatomy based on these MR images and to adapt the treatment accordingly. MR image sequence parameters and image registration need to be jointly optimized to allow dose tracking to deliver on the promise of precision radiotherapy with the MRlinac.

This presentation will briefly sketch the background and development of the MRlinac, the clinical introduction and promises and the route towards real-time adaptive radiotherapy.