There is no doubt that smoking significantly increases the risk of lung cancer. However, smoking is an addiction, and many do not succeed in their attempts to quit. An ultra-low-dose computer tomography of the lung (thorax) is recommended for all long-time smokers over the age of 50. Potential changes (cancer, emphysema, bronchitis) can be visualised at an early stage with these images. And yet: Benign and malignant changes cannot always be differentiated with a CT scan – follow-up examinations are often required.