- Tumor must be within or touching the zone of the proximal bronchial tree, defined as a volume of 2 cm in all directions around the proximal bronchial tree (i.e., carina, right and left main bronchi, right and left upper lobe bronchi, intermedius bronchus, right middle lobe bronchus, lingular bronchus right, and left lower lobe bronchi) OR immediately adjacent to the mediastinal or pericardial pleura (PTV touching the pleura)