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Updated: Feb 16, 2026
Three-Dimensional Finger Motion Tracking during Needling: A Solution for the Kinematic Analysis of Acupuncture Manipulation
Published on: October 28, 2021
Analysis of intrafraction motion in CyberKnife-based stereotaxy using mask based immobilization and 6D-skull
Tejinder Kataria1, Kushal Narang1, Deepak Gupta1
1Division of Radiation Oncology, Medanta Cancer institute, Medanta The Medicity, Sector 38, Gurgaon, Haryana, 122001, India.
Purpose:
Analysis of intrafraction motion in patients with intracranial targets treated with frameless, mask based stereotactic radiosurgery / radiotherapy using standard couch and 6D-skull tracking on CyberKnife.
Materials And Methods:
Twenty-seven treatment datasets of fifteen patients were analyzed. For each sequential pair of images, the correction to the target position (position "offset") in six-degrees of motion was obtained. These offsets were used to calculate intrafraction shifts, and their statistical distribution. PTV margins were calculated, based on Van Herk formula.
Results:
The mean ± 1 SD intrafraction translationals were 0.27±0.61mm in left-right, 0.24±0.62mm in antero-posterior and 0.14±0.24mm in supero-inferior direction, and rotations were 0.13±0.21 degrees roll, 0.18±0.25 degrees pitch and 0.28±0.44 degrees yaw. Most intrafraction shifts were ≤ 1mm and 1 degree. Fourteen instances of intrafraction shifts exceeding the robotic correction threshold were noted. Calculated PTV margins were 1mm, 1mm and 0.4mm for for left-right, antero-posterior and supero-inferior directions, respectively.
Conclusions:
CyberKnife 6D-skull tracking with 1mm PTV margin effectively compensates for intrafraction motion. The occasional large intrafraction movements may assume significance for techniques not employing intrafraction motion management.
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