Program Information
An Unified Imaging and Robotic Couch Quality Assurance Procedure and Automation Software
E Schreibmann* E Elder, Department of Radiation Oncology, Winship Cancer Institute of Emory University
Presentations
SU-E-T-113 (Sunday, July 12, 2015) 3:00 PM - 6:00 PM Room: Exhibit Hall
Purpose: To introduce a quality assurance (QA) procedure for the robotic 6DoF couches integrates the couch and imaging components QA procedures into a simple workflow.
Method: Current QA procedure for the imaging systems is to carefully align a phantom at isocenter and measure in images acquired using the on-board imaging (OBI) system if the phantom appears aligned with the isocenter. For the robotic couches a complementary procedure offsets a phantom from to measure the couch’s ability to reposition the phantom at isocenter. We propose a two-in –one procedure that starts with a phantom displaced with random positions and orientation and asks the imaging system to align it back at isocenter. Accuracy is measured by comparing the repositioned phantom againts the treatment field. A software module was also implemented to analyze, quantify and report the results.
Results: The procedure has been implemented clinically using a SRS calibration phantom (VisionRT, London, UK) and the automated software version that is able to detect errors of less than 0.1 mm or 0.1 degrees. The software detects the markers locations with a combination of contouring and intensity filters to compute the shifts/rotations needed to reposition the phantom to it’s ideal location using a interactive closest point algorithm to match markers segmentations as extracted from imaging with a mesh representation of their expected location according to the phantom specifications. Once the shifts are send to the couch for repositioning, the procedure is repeated to measure the residual error in imaging to measure robotic couch repositioning accuracy and the phantom location against the graticule is verified.
Conclusions: A simplified QA procedure and the associated software are presented to streamline the quality assurance of imaging and 6D couch components into a single, easy-to-use procedure.
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