Robotic stage for head motion correction in stereotactic radiosurgery

A novel 4 Degree-of-freedom (4D) robotic system was developed to correct both translational and rotational head motion deviations during image-guided stereotactic radiosurgery procedures. The correction was non-invasive, and was performed in real-time with high positioning accuracy. An optical system was used for real-time 6D head position tracking, and a decoupling control law was designed to control the 4D stage for the motion correction in xyz direction and pitch angle. Both experiments on an phantom and volunteers was used to demonstrate the control performance. With motion correction, on average, over 99% of the time the translational error was within 0.5 mm, and the pitch angle error was within 0.2 degrees.