Set-up errors in head and neck cancer patients treated with intensity modulated radiation therapy: Quantitative comparison between three-dimensional cone-beam CT and two-dimensional kilovoltage images

A similar sensitivity to linear set-up errors was observed for 2D-kV and 3D-CBCT image guidance techniques in our H&N patient cohort. Higher rotational deviations around the table vertical axis were detected by the 3D-CBCT with respect to the 2D-kV method, leading to a consistent better sparing of organs at risk.