Fig. 1From: Normal lung sparing Tomotherapy technique in stage III lung cancerIn order to lower dose to lung, complete and directional blocks were delineated within lung (a). These were located as from PTV as possible, and complete blocks did not allow any beams to pass through them, while directional blocks allowed beams only if they entered PTV first. In order to generate the principles of delineating the complete and directional block, authors collected and analyzed the data of beam arrangements (red dots) in L-IMRT that were actually applied to 59Â N3-IIIB NSCLC patients at our institute (b). Dotted arrows represented the most used beam angles for L-IMRTBack to article page