“…Among such factors, the ones that appear with most frequency in published studies are the lung volume receiving >20 Gy (1,(9)(10)(11)(12)(13)(14)(15), lung volume receiving >30 Gy (9,14,16,17), and the mean lung dose (1,11,15,(17)(18)(19)(20). Other factors that have been identified are the lung volume receiving >5-13 Gy (21), >15 Gy (9), >40 Gy (14), and >45 Gy (14) and the tumor lobe location (22)(23)(24). In two recent studies, Kong et al (1) identified the lung volume receiving >20 Gy and the mean lung dose, and Hope et al (24) identified lower lobe tumor location, maximal lung dose, and minimal dose to the 35% volume receiving the highest doses as predictive of lung radiation pneumonitis.…”