Related Experiment Video
Updated: Jan 12, 2026

Movement Retraining using Real-time Feedback of Performance
Published on: January 17, 2013
Significance of positional correction of planned couch angles with the ExacTrac system
Hideharu Miura1,2, Minoru Nakao1,2, Shuichi Ozawa1,2
1Hiroshima High-Precision Radiotherapy Cancer Center, Hiroshima, Japan.
Abstract:
This study evaluated the benefits of the ExacTrac system for non-coplanar beams in brain stereotactic radiotherapy (SRT) by comparing pre- and post-X-ray verification (XV) positioning data. Data from 62 patients undergoing brain SRT were analyzed, focusing on 151 non-coplanar beams. Patient positioning involved initial infrared marker alignment, followed by ExacTrac kV x-ray acquisition and 6D robotic couch adjustments. Patient positioning was corrected within a tolerance of 0.5 mm and 0.5° for translation and rotation, respectively. Pre and post-XV positioning data were compared at each planned couch angle. Results showed that 54% of non-coplanar beams had positioning errors exceeding the specified tolerances on the pre-XV. Significant differences were observed in translational and rotational corrections between pre- and post-XV positioning at each planned couch angle. These results demonstrate that XV at any each planned couch angle using the ExacTrac system significantly improves patient positioning accuracy in brain SRT.
Related Concept Videos
Adjusting a Traverse
Distance Corrections
Relative Motion Analysis - Acceleration
Errors in Taping
Relative Motion Analysis using Rotating Axes-Problem Solving
Here, in order to determine the magnitude of velocity and acceleration for point...
Relative Motion Analysis using Rotating Axes
However, to express the relative position of point B relative to point A, an additional frame of reference, denoted as x'y', is necessary. This additional frame not only translates but also rotates relative to the fixed frame, making it...

