PRIMER: Development of Daily Online Magnetic Resonance Imaging for Magnetic Resonance Image Guided Radiotherapy

In radiotherapy high-tech scans with x-rays (CT scans) are taken before and during treatment to locate the tumour and ensure the radiation is hitting the target. These x-rays expose patients to additional radiation and the quality of these scans is often poor which makes it difficult to distinguish tumour from normal tissue and there may be uncertainty in the tumour position due to movement or shrinkage. To allow for these uncertainties a large margin around the tumour is also treated, but this means that large volumes of normal tissue also receive significant doses of radiation, which can result in early and late toxicity. MRI (magnetic resonance imaging) is better than CT scanning at being able to tell the difference between tumour and normal tissues and does not expose patients to additional radiation. A new machine called an MR Linac (or magnetic resonance imaging-guided linear accelerator) integrates high quality MRI with a state-of-the-art radiotherapy machine and the Institute of Cancer Research (ICR)/The Royal Marsden Hospital (RMH) are currently installation a prototype, which will be one of the first in the world. This revolutionary technology has the potential to change the way radiotherapy is delivered. We hope the improved precision and accuracy in hitting the target will mean reductions in margins around tumours and that this will lead to higher cure rates with significantly fewer side effects. Studies are required to simulate treatment on the MR Linac before it can be used in routine clinical practice and to conduct these studies, we need to obtain MRI scans on volunteers and patients who are currently undergoing treatment. This study will involve imaging with MRI in healthy volunteers as well as in patient volunteers before and during their standard course of radiotherapy to allow us to develop MRI sequences derived on the MR Linac for MR Linac-based research focusing on clinical application and establishment into a MR-CT and MR only workflow, treatment adaptation and quality assurance.