Respiratory-induced organ motion significantly affects delivery of radiotherapy and the quality of diagnostic imaging in the thoracic and upper abdominal region. Consequently, larger volumes to treat the tumor adequately are needed for radiotherapy; during diagnostic imaging motion may deteriorate image quality. An increasing number of studies report on applying non-invasive ventilation (NIV) in conscious subjects to change the breathing pattern for a specific radiation treatment or image acquisition. A comprehensive overview of the evidence on applications of NIV however is lacking. Therefore, we will create an evidence map to provide clarity on NIV types applied in conscious subjects and summarize evidence on the clinical purposes.