A Feasibility Study of MRI Guided Stereotactic Ablative Radiotherapy (MIDSECTION)

Stereotactic Ablative Radiotherapy (SABR) for tumours in the thorax and abdomen is becoming the standard of care for patients with small, localised disease. Recent publications and guidelines provide evidence for safe, effective treatment prescriptions in most of these tumour sites. However this guidance is based on the use of x-ray based guidance systems, without the use of functional imaging or real-time adaptation. To investigate the potential benefits of MRI-guided SABR, including superior at-treatment imaging, gating, real-time adaptation and the integration of functional or biological information, the investigators propose to undertake MR-guided SABR using established guidance. In doing this the investigators will be able to evaluate the patient experience (for example the MR Linac is considerably noisier than a standard treatment machine); the investigators will be able to acquire images (with no additional radiation) to interrogate motion, and deformations in real-time to assess whether or not real time adaptations would benefit the patient experience and/or outcomes; the investigators will be able to compare the outcomes of the patients treated on a machine with superior imaging to those undergoing the same (or similar) treatment on standard machines using the UKCAT database; the investigators will be able (should participants choose to give consent) to acquire research images interrogating tumour and normal tissue physiology/biology and determine if and how this information may be able to improve treatments and/or predict response. For these reasons it is important to make this change in practice (from x-ray guided SABR to MRI-guided SABR) within the confines of an observational clinical study.