Lung function diagnostics has continuously developed and validated by ventilation/perfusion tomography (V/P SPECT) for diagnosis of pulmonary embolism (PE). More than 17 000 scans have been performed at our department in the last 15 years. Marika Bajc is leading the research, also being the leader for EANM Guidelines in which our method was accepted as the primary diagnostic tool for PE. Collaboration is continuing with Sarajevo University (Begic), with particular interest to study duration of anticoagulant treatment to personalize medicine. Studying chronic PE is also a part of multicentre Swedish study lead by S. Söderberg. V/P SPECT is the only functional imaging method to assess ventilation. Our focus is now to study chronic obstructive lung disease/asthma and co-morbidities such as heart failure, pulmonary hypertension and pneumonia, in collaboration with L.Bjermer, and by running a multicentre clinical trial in China. Collaboration with Japan has started (K.Suga).