Inflammatory lung disease is one of the most common clinical scenarios, and yet, it is often poorly understood. Inflammatory lung disorders, such as chronic obstructive pulmonary diseases, which are causing significant mortality and morbidity, have limited therapeutic options. Recently, new treatments have become available for pulmonary fibrosis. This review article will describe the new insights that are starting to be gained from positron emission tomography (PET) methods, by targeting molecular processes using dedicated radiotracers. Ultimately, this should aid in deriving better pathophysiological classification of these disorders, which will ultimately result in better evaluation of novel therapies. (C) 2016 Elsevier Ireland Ltd. All rights reserved.