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Session: Multi-Disciplinary General ePoster Viewing [Return to Session]

Comprehensive Evaluation of AlignRT V6.3 “Send to Couch” Function for SGRT Applications

X Zhai1*, Y Liang2, B Mueller1, G Li1, Y Song1, (1) Memorial Sloan Kettering Cancer Center, New York, NY, (2) Columbia University, New York, NY,


PO-GePV-M-219 (Sunday, 7/10/2022)   [Eastern Time (GMT-4)]

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Purpose: The “Send to Couch” function in AlignRTv6.3 offers an automated one-button solution to a complex 6D patient setup task from surface image acquisition to Linac couch shifts. Before its clinical implementation, we comprehensively evaluated its performance, compared its accuracy to pre-set 6DOF couch positions and CBCT imaging, and verified that actual couch shifts were the same as those calculated by surface registration.

Methods: Varian TB 6DOF couch was used as the ground truth in evaluations. Five disease sites were investigated, including the brain, chest wall, intact breast, abdomen, and leg, using four different types of phantoms. For translational evaluations, the couch moved in step of 0.5cm from 0.5cm to 4.5cm, and 4.8cm. For rotational evaluations, the couch rotated in step of 0.5⁰ from 0.5⁰ to 3.0⁰. For each movement step, “Send to Couch” was used to measure couch shift. For End-to-End tests, actual couch shifts were compared with those determined by CBCT imaging and “Send to Couch” before and after applying couch shifts. Pass/Fail-tolerances were ±0.3mm/±0.2⁰ for the “Send to Couch” function and ±0.1mm/±0.1⁰ for actual couch shifts.

Results: Ninety-six evaluation tests were performed for each disease site. 100% tests for the breast, brain, and abdomen were within Pass/Fail-tolerances. 98% tests were within tolerances for the chest wall. 79% tests were within tolerances for the leg. For End-to-End tests on the brain, 83% of shifts calculated by “Send to Couch” were within tolerances. 100% actual couch shifts were within ±0.1mm/±0.1⁰-tolerances.

Conclusion: AlignRT v6.3 “Send to Couch” function performed well for most disease sites based on ±0.3mm/±0.2⁰-tolerances. For disease sites with rotational symmetry and/or without registration landmark, such as the extremities, a large asymmetric ROI is recommended to mitigate symmetry issues and improve measurement accuracy. Alternatively, the legs can be bent inside the mold for simulation and treatment.

Funding Support, Disclosures, and Conflict of Interest: This project is funded by the Rose-Margulies Family Research Fund.


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