Program Information
Independent Evaluation of the Stability of CBCT-Defined Stereotactic Space in Gamma Knife Icon
I AlDahlawi*1,2, D Prasad1,2, M B Podgorsak1,2, (1) State University of New York at Buffalo, Buffalo, NY, (2) Roswell Park Cancer Institute, Buffalo, NY
Presentations
SA-B-BRA|B-1 (Saturday, March 18, 2017) 10:30 AM - 12:30 PM Room: Ballroom A|B
Purpose: The Gamma Knife Icon comes with an integrated Cone-beam CT (CBCT) for image guided stereotactic treatment deliveries. The CBCT can be used for defining the Leksell stereotactic space using imaging without the need for the traditional invasive frame system. In this study, we used an in-house built marker tool to evaluate the stability of the CBCT-based stereotactic space and its agreement with the standard Frame-based stereotactic space.
Methods: We imaged the tool with a CT indicator box using our CT-simulator at the beginning, middle, and end of the study period (six weeks) for determining the Frame-based stereotactic space. The tool was also scanned with the Icon’s CBCT on a daily basis throughout the study period, and the CBCT images were used for determining the CBCT-based stereotactic space. The coordinates of each marker were determined in each CT and CBCT scan using the Leksell GammaPlan treatment planning software, and the magnitudes of vector difference between the means of each marker in Frame-based and CBCT-based stereotactic space were noted.
Results: The magnitudes of vector difference between the means of each marker in Frame-based and CBCT-based stereotactic space ranged from 0.21 to 0.33 mm, indicating good agreement of CBCT-based and Frame-based stereotactic space definition. Scanning four-months later showed good prolonged stability of the CBCT-based stereotactic space definition.
Conclusion: A simple in-house tool was used to test the stability of the CBCT defined stereotactic space in Gamma Knife Icon and its agreement with the standard Frame defined stereotactic space, independently from the manufacturer provided tool and methodology. CBCT-based stereotactic space definition in Gamma Knife Icon was found to be stable over a period of four months, and in good agreement with the standard Frame-based stereotactic space definition.
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