Interfraction Displacement of Primary Tumor and Involved Lymph Nodes Relative to Anatomic Landmarks in Image Guided Radiation Therapy of Locally Advanced Lung Cancer

Carina-based setup results in a more reproducible PT and LN alignment than bony anatomy setup. Considering the independence of PT and LN displacement and the impact of volume regression on displacements over time, repeated CT imaging even with PT-based alignment is recommended in locally advanced disease.