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Validating the Use of Surfacing Mapping Tools for Motion and Irregular Breathing Pattern Monitoring On Lung SBRT Patients

X Xie

X Xie*, D Cao , V Mehta , D Shepard , Swedish Cancer Institute, Seattle, WA


SU-E-T-788 (Sunday, July 12, 2015) 3:00 PM - 6:00 PM Room: Exhibit Hall

Validating the Use of Surfacing Mapping Tools for Monitoring Motion and Irregular Breathing Patterns for Lung SBRT Patients

Purpose: In this study, we have examined the utility of surface mapping in the treatment of lung SBRT patients. We examined the extent to which intra-fraction patient motion and irregular breathing patterns impact the accuracy of treatment deliveries.

Materials and Methods: The C-RAD Catalyst, an optical surface mapping system was used to track the intra-fractional isocenter motion of five lung SBRT patients treated with VMAT. A respiratory tracking tool was used to track the breathing pattern of these patients and to correlate the breathing pattern to the isocenter motion.

Results: For 2 of the 5 patients the isocenter displacement exceeding the 5mm planning margin for a portion of the treatment delivery with the time outside of tolerance at 2.2%, and 2.5%.

Conclusions: 1) Breathing patterns may change between different fractions for the same patient; 2)Breathing patterns can change from the beginning to the end of the same fraction; 3) Not only amplitude, but also the baseline of breathing may change during an individual fraction; 4) We cannot predict which patients will have a stable isocenter in treatment even after the simulation study; and5)Real-time motion monitoring with surface-mapping tools and respiratory gating (free breathing or breath-hold) may provide clinically valuable solution in motion management for lung SBRT patients.

Funding Support, Disclosures, and Conflict of Interest: The research is supported by funding from Elekta.

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