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Program Information

Combining Catalyst HD and SBRT Positioning Systems

S Fakhraei

S Fakhraei*, D Sterling , E Ehler , C Conduah , P Alaei , University of Minnesota, Minneapolis, MN


SU-I-GPD-J-78 (Sunday, July 30, 2017) 3:00 PM - 6:00 PM Room: Exhibit Hall

Purpose: Combining the use of C-RAD Catalyst HD with SBRT positioning systems to assess its usability for lung SBRT treatments utilizing the frames and compression paddles.

Methods: A Rando phantom was positioned in three SBRT positioning systems made by Elekta, CIVCO, and Bionix. The phantom was CT scanned inside each frame utilizing both Vac-Lok bags and compression paddles. The images were exported to a treatment planning system where external contours were generated and exported to the C-RAD system to use as reference images. Each setup was then reproduced in a Varian linac room equipped with C-RAD Catalyst HD system and the surface area of the phantom visible using each camera was assessed. In case of Bionix frame both the rigid paddle and the respiratory belt were examined. The placement of a respiratory trace was also evaluated.

Results: The phantom surface area visible varies depending on the system used, with Bionix providing the largest visible area. Due to the variations of the colors of the frames, there are obvious differences in the amount of reflection of each frame and the degree in which they obstruct the skin rendering. Depending on the color of the SBRT frame and its contrast with surface, the frame may be automatically excluded from surface allowing only the phantom surface be monitored by Catalyst. Compression paddles hinder the visualization of respiratory trace points, with the Bionix respiratory belt having the least effect.

Conclusion: Combining the use of Catalyst with SBRT positioning frames adds another level of accuracy to patient setup and provides for monitoring of the movement during treatment. Utilizing the SBRT frames with chest compression, volumetric imaging and surface imaging for patient setup, and motion management using surface imaging during treatment, may reduce the uncertainty associated with SBRT.

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