MODEL RELEASED. Studying CT scan. Doctor studying a computed tomography (CT) scan of a horizontal section through the chest of a patient with mesothelioma. Mesothelioma is a type of lung cancer. It affects the pleura, the membrane that lines the lungs and chest cavity, and is usually associated with exposure to asbestos. CT scanning is a diagnostic technique that uses X-rays to build up images of slices through the body. Photographed in the Department of Oncology, Newcastle General Hospital, UK.