Air from the upper respiratory tract enters the bronchi and eventually to the lungs where gaseous exchange takes place. Oxygen enters the blood while metabolic waste i.e., carbon dioxide moves out of the body. Lungs are formed to provide a large surface area where gases are exchanged. Symptoms of lung diseases include difficulty in breathing, coughing, and exercise intolerance. Radiograph images are taken to visualize the lungs and diagnose the problems such as the presence of inflammation, infection, and tumor.