Gkteso - Model 6DoF -Robotic Couch for Image Guided Radiotherapy

Why Precision Fails in patient positioning

Accurate targeting defines success in radiation therapy. Yet even submillimeter deviations in positioning can alter the radiation path and compromise treatment outcomes. The following challenges show why fixation alone cannot guarantee precision.

Angular Deviations

Even minimal rotational shifts in pitch, roll, or yaw can displace the treatment isocenter by several millimeters. This reduces dose conformity and compromises tumor targeting accuracy particularly in hypofractionated and stereotactic radiotherapy.

Intrafraction Motion

Patient relaxation, anatomic changes or mask inherent tolerances can introduce subtle movements that remain undetected. These micro-motions alter the beam path and affect dose delivery to critical structures near the tumor.

Limited Post-Fixation Adjustment

Once the thermoplastic mask is fixed, most immobilization systems cannot correct angular errors. This limits precision in adaptive or image-guided workflows, especially when CBCT imaging reveals small misalignments.

Reproducibility Between Fractions

Even with identical mask setups, geometric variation occurs across treatment sessions. Without integrated motion correction, these inconsistencies reduce reproducibility and complicate dose planning for fractionated or stereotactic protocols.