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Session: Quality Control in Treatment Planning and Delivery [Return to Session]

6-DoF Robotic Motion Phantom: An Open-Source Project for Quality Assurance of Real-Time Image-Guided Radiotherapy Technologies

C Sengupta1*, S Alnaghy2, D Nguyen1,3,4, A Kyme5, K Makhija1, T Moodie6, D Mason7, V Caillet1, K Shi1, R O'Brien1, J Booth4, S Tomka1, P Keall1 (1) ACRF Image X Institute, The University of Sydney, Sydney, NSW, AU, (2) Centre for Medical Radiation Physics, University of Wollongong, NSW, AU, (3) University of Technology Sydney, Ultimo, NSW, AU, (4) North Sydney Cancer Centre, Royal North Shore Hospital, NSW, AU, (5) School of Biomedical Engineering, The University of Sydney, NSW, AU, (6) Crown Princess Mary Cancer Centre, NSW, AU, (7) Nepean Cancer Care Centre, NSW, AU


WE-D-TRACK 1-7 (Wednesday, 7/28/2021) 2:00 PM - 3:00 PM [Eastern Time (GMT-4)]

Purpose: The geometric and dosimetric impact of tumor translation and rotation, or 6-degree-of-freedom (6-DoF) motion, in radiation therapy is becoming increasingly important. Since there is currently no commercial 6-DoF solution that could reproduce patient-measured motion, we designed, built and programmed a robot-based system for 6-DoF Image-guided Radiation Therapy (IGRT) research and Quality Assurance (QA). To enable advancement of intrafraction motion management in our community, we have made the complete package open-source. The purpose of this work is to describe the applications of the 6-DoF system, the research results and the open-source repository.

Methods: The 6-DoF system consists of a six-axis robotic arm (Universal Robot, UR3), an acrylic phantom, a custom-base plate to mount the robotic phantom onto the treatment couch and a software application which controls the robotic phantom to reproduce the patient-measured tumor motion. The integrated system is capable of accurately mimicking patient-measured tumor traces to provide precise 6-DoF QA for real-time IGRT approaches. The repository contains everything required to assemble a similar 6-DoF system: source code, CAD files for the phantom and hardware tools, robot specifications, bill of materials, documentation, and user-guide to operate the system, and, step-by-step QA procedure.

Results: The 6-DoF system has been used successfully for several applications including geometric QA tests for the real-time tumor tracking technology, Kilovoltage Intrafraction Monitoring (KIM) in two multi-center clinical trials, for prostate and liver cancer patients and evaluation of the dosimetric impact of prostate rotational motion using films.

Conclusion: The development of this system has enabled us to perform 6-DoF QA processes for KIM and it has great potential to perform QA for other real-time radiotherapy systems. Full details of the system and its application have been shared on GitHub for the benefit of the medical physics community:

Funding Support, Disclosures, and Conflict of Interest: P Keall is supported by an NHMRC Investigator (L3) grant. D T Nguyen is supported by NHMRC and Cancer Institute NSW Early Career Fellowships. Nguyen, O'Brien and Keall are listed inventors on KIM-related patents. Nguyen and Keall are stock-holders of SeeTreat Pty.



    Quality Assurance


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