Conclusions
• Intra-fraction movement in a mask is about 0.2 - 0.3 mm,
registration accuracy comparable
• With automatic couch shift, the accuracy of IGRT is
extremely high
• Rotational errors have a negligible effect for CTV coverage
in most cases
• Cone-beam CT guidance of stereotactic treatments achieves
comparable results to methods based on invasive frames
• Post treatment scan important to validate workflow