AbstractID: 9310 Title: 3D correlation analysis between body marker and target motion
for breath gating control
A 3D motion correlation between body marker and target is investigated for breath gating control
during radiosurgery of lung and abdomen tumors. In this study, the body marker positions are
recorded by infrared cameras and the target positions are recorded by real-time fluoroscopic
imaging. The acquired data (the record sequences of marker and target motions) are preprocessed by removing their mean values and scaling to the identical range. The phase shift is
be identified by detecting the peak point in the cross-covariance sequence between two recorded
sequences and corrected later. Then the correlation coefficient between two processed
sequences and point-to-point ratios are calculated in 3D. Using this procedure (including preprocessing and correction of phase shift), three sets of breath gating data (two lung patients and
one pancreas patient) were processed. Comparing the results before and after correction of
phase shifting, both average correlation coefficient and the deviation of average ratio are
improved by a factor 2 for all processed data. It is noted that the improvement amount also
depends on the marker’s location and its dimension. These results indicate that there is a high
correlation between motions of markers and target, which can be utilized to further improve the
current techniques for breath gating control.
This study is partially supported by a research grant from BrainLAB.