Procedures in all patients will be carried out under conscious sedation and/or anaesthesia. After bronchoscopic examination of the airways, 100ml of the patients own blood will be collected using two 50ml syringes. A balloon catheter will be inserted into the target segment and 25 mls of the blood will be injected via the balloon catheter. The balloon will be inflated and maintained in position for about 6 minutes in order to minimise the risk of overspill of blood into other areas of the lung. The balloon catheter will then be repositioned in the next segment of the target lobe of the lung and the process repeated until all the segments are treated. It is anticipated that the whole procedure will last 45-60 minutes, up to and including balloon removal.