Functional Lung Avoidance SPECT-guided Radiation Therapy of Lung Cancer

Inclusion Criteria: * histologically verified lung cancer (small-cell and non-small cell lung cancer) * referred for radiotherapy with curative intent * radiation dose of 60-66 Gy given in 2-Gy fractions, other dose levels and fractionation schedules accepted, as per site standard * concurrent chemotherapy is accepted * patients with oligometastatic disease are allowed, where metastasis have been ablated with surgery or radiotherapy * receiving (chemo)-radiotherapy to the thoracic disease with curative intent * adults over 18, that have given oral and written informed consent before patient registration. Exclusion Criteria: * concurrent immunotherapy * previous radiotherapy to the thorax * other uncontrolled malignancies; any psychological, familial, sociological or geographical condition potentially hampering compliance with the study protocol