Magnetic Resonance Imaging (MRI) for the Delineation of Organs At Risk (OAR) and Target Volumes in Lung Cancer Patients

The Christie NHS Foundation Trust is one of seven sites worldwide within the Atlantic consortium that is developing the Elekta MR-Linac (MRL) prior to commercial release at the end of 2017. The MRL allows MR images of patients to be acquired before, during and following radiotherapy (RT). One area where The Christie is taking the lead within the consortium is the application of the MRL for lung imaging and treatment, an area where MRI has hardly been used. MRI scans provide greater soft tissue contrast than CT scans which can aid in the accurate delineation of organs at risk (OAR) and tumour target volumes for MRL and routine treatment. In addition, MRI can provide real time imaging which can aid in the accurate motion characterisation of these volumes. The addition of functional diffusion weighted imaging (DWI) has also proven to be useful in the discrimination of malignant from benign lesions; for lymph node detection and for the differentiation of tumour from atelectasis. Auto-contouring has the potential to speed workflows at various points in the clinical pathway. This may be inter-patient contour propagation used pre-treatment for plan creation, or may be during online or offline adaptive workflows propagating contours through imaging acquired as treatment progresses. In collaboration with industry the investigators will be testing such algorithms on these images retrospectively. In addition, the investigators would also like to evaluate patients' experiences of CT and MRI scans and determine which scanning method is preferred. Other studies have explored patient experiences of MRI compared to CT but not in the lung cancer patient population.