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SU‐E‐T‐512: Targeting Mobile Tumors Precisely with an Integrated Robotic Target Tracking and Dynamic Couch‐Based Motion Compensation System for a Conventional Linear Accelerator
Author(s) -
Shah D,
McAvoy T,
Malinowski K,
DˈSouza W
Publication year - 2011
Publication title -
medical physics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.473
H-Index - 180
eISSN - 2473-4209
pISSN - 0094-2405
DOI - 10.1118/1.3612465
Subject(s) - imaging phantom , computer science , tracking (education) , tracking system , latency (audio) , match moving , computer vision , compensation (psychology) , motion compensation , artificial intelligence , standard deviation , controller (irrigation) , motion (physics) , kalman filter , optics , physics , mathematics , psychology , telecommunications , pedagogy , agronomy , statistics , psychoanalysis , biology
Purpose: To introduce a novel, integrated tumor tracking and dynamic robotic couch‐based target motion compensation system with a conventional linear accelerator and to evaluate system accuracy. Methods: We have developed an integrated real‐time tumor tracking and motion compensation system using the treatment couch. The system comprises an infra‐red (IR) camera system capable of tracking optical reflectors placed on or near a target at a rate of 60 Hz, a robotic couch that is controlled in real‐time and the embedded couch controller capable of feedback control. System accuracy was tested using, a 4D phantom, placed on the couch and programmed to simulate 20 time‐varying 3D tumor motion (derived from patient tumor trajectories) with peak‐peak displacements of up to 4 cm. The position of the optical reflector was maintained at the reference position by tracking it with the robotic couch. Camera lag, system latency and tracking errors were evaluated. Dosimetric accuracy was also studied between with and without motion compensation.Results: In the absence of the IR camera (phantom‐couch direct positive feedback control), the system latency is < 0.5 ms. The IR camera introduces a 17 ms delay in the control system. This lag induces an overall system latency of 67–150 ms. In the absences of the camera, the robotic system achieved with standard deviation for tracking errors accuracy of 0.01 mm, 0.03 mm and 0.04 mm in ML, AP and SI directions, respectively. The integrated system achieved standard deivation for tracking error accuracy of 0.5 mm in all three in ML, AP and SI directions, respectively. Dosimetric accuracy was improved by 11–36% Conclusions: We have developed a viable and integrated tumor tracking and real‐time robotic couch‐based target motion compensation system that may be integrated with a conventional linear accelerator, obviating the need for a specialized radiation delivery device. Supported by grant #CA122403 from the NCI