Local Setup Errors in Image-Guided Radiotherapy for Head and Neck Cancer Patients Immobilized With a Custom-Made Device

Local deformations in head-and-neck patients occur even if an elaborate, custom-made patient fixation method is used. A rotational error correction decreased the required margins considerably. None of the considered correction strategies achieved perfect alignment. Therefore, weighting of anatomic subregions to obtain the optimal correction vector should be investigated in the future.