Click here to


Are you sure ?

Yes, do it No, cancel

Computer Aided Selection of Optimal Phase Windowing for Moving Targets

Y Yuan1*, R Cardan1 ,(1) UAB University of Alabama, Birmingham,AL


(Sunday, 7/14/2019)  

Room: ePoster Forums

Purpose: Treatment planning using 4D images is often qualitatively or quasi-quantitatively performed to find phases of the breathing cycle where target motion is minimal. This study proposes a computer-aided guidance instead to determine the optimal gating window for treatment.

Methods: A 4D CT scan was retrospectively analyzed for a clinically treated lung patient. Using the 10 binned phases (P₀₀ – P₉₀) from the CT series, a deformable registration was performed between each phase and the maximum exhale phase (P₅₀). The resulting vector fields were analyzed which were in the 3D bounding box of the physician drawn target and all other vectors were discarded. Target motion was analyzed by tracing the voxel extents between all possible phases and the percent volume of target migration was recorded in each phase range. Finally, an optimal phase range was proposed which contained at least 95% of the target within 5 mm while maximizing the treatment window.

Results: The percent target migration was plotted for each of the 20 different phase combinations (P₀₀– P�₀, P₀₀–P₂₀, … P₈₀ – P₉₀). Using the technique described, the phase range P20-P80 was found to maximize the treatment efficiency while maintaining 95% of the target within 5 mm of the maximum exhale position.

Conclusion: We proposed an innovative way to quantitatively define the optimal treatment window for moving targets. Future work includes validating results with phantom measurements.


Not Applicable / None Entered.


Not Applicable / None Entered.

Contact Email