Computed Tomography Assessment of Regional Ventilation (CURVE)

This study uses CT scans to assess airflow in the lung, the scan is quick, cheap and painless. The information from the scan may help doctors tell which patients are suitable to have surgery to cure early stage lung cancer. It may also help doctors tell which patients would benefit from surgery for emphysema and diagnose types of lung disease. The investigators will follow up patients who go through surgery to test how well the scan predicts the function of the lung after surgery. The investigators will follow patients being investigated for lung disease to test how accurate the scan is at the getting the diagnosis right.