adding 5 mm in all directions (excluding the chest wall). The internal margin (IM) was determined by the tumor
motion demonstrated in 4-D CT images to encompass residual respiratory tumor motion. The planning target
volume (PTV) included the CTV, IM, and setup margin (3 mm). The Gating window was set to 30 % of the expiratory phase to 30 % of the inspiratory phase to minimize the influence of tumor respiratory motion. Planning are described in a previous study.