Assessment of Intrafraction Mediastinal and Hilar Lymph Node Movement and Comparison to Lung Tumor Motion Using Four-Dimensional CT

Four-dimensional CT scans can be used to measure the motion of the primary lung tumor and pathologic lymph nodes encountered during the respiratory cycle. Both the primary lung tumor and the lymph node must to be examined to assess their individual degree of motion. This study demonstrates the need for individualized plans to assess the heterogeneous motion encountered in both primary lung tumors and among lymph node stations.