A Comparison of Internal Target Volume Definition by Limited Four-dimensional Computed Tomography, the Addition of Patient-specific Margins, or the Addition of Generic Margins when Planning Radical Radiotherapy for Lymph Node-positive Non-small Cell Lung

Further work is required to determine whether end-tidal breath-hold scans are representative of the anatomy at the limits of tidal respiration. Planning strategies are also needed to account for breathing cycle variation during a course of radiotherapy.