The University of Sheffield is one of the leading centres in the world for basic and translational research with inhaled gas MRI, which provides lung images with unprecedented spatial and temporal resolution. Our previous work demonstrated that inhaled gas MRI can provide significant clinical information for lung cancer radiotherapy planning and post-treatment evaluation. Building upon this unique experience, a multidisciplinary team will conduct an inhaled gas and proton lung MRI study that will address two of the major clinical problems faced by lung cancer patients treated with radiotherapy.

1. Normal lung tissue is often damaged by the curative radiation dose. The investigators hypothesise that regional ventilation-perfusion lung function imaging with inhaled gas and proton MRI before and after treatment will help to lower the risk of radiation-induced lung injury and help to detect such damage at an early stage.
2. Identification of the extent of cancerous tissue is error-prone when planning treatment from CT images alone. The investigators hypothesise that advanced proton MRI techniques will improve the identification of tumour volume, which is critical to successfully targeting the radiation dose.

To achieve these goals, image acquisition and image processing methods will be tested with a study of 20 patients. Results from this study will make an important contribution to improving the treatment of lung disease which is one of the key research priorities of the NHS.

Inclusion Criteria:

• Patients with an MDT diagnosis of NSCLC based on findings of positive histology, positive PET scan or growth on serial CT scan requiring CT planning for radiotherapy treatment
• patients aged over 18
• patients able to undergo MRI scanning.

Exclusion Criteria:

• patients with co-morbid conditions that exclude radiotherapy treatment
• patients who are pregnant or women with child bearing potential
• patients unable to give informed consent
• patients who do not understand English sufficiently to read the patient information sheet, provide informed consent or converse with research staff without interpreters.

Patients with NSCLC attending Weston Park Hospital, Sheffield, UK.