Program Information
A Novel Metal-Free Miniature 6D Robotic Couch - to Correct Head and Neck Positioning When They Have Differing Displacements
M Ostyn*, T Dwyer, D Martinez, R Cruikshank, M Miller, P King, R Sacks, WH Yeo, S Kim, Virginia Commonwealth University, Richmond, VA
Presentations
SU-I-GPD-T-81 (Sunday, July 30, 2017) 3:00 PM - 6:00 PM Room: Exhibit Hall
Purpose: Steep dose gradients and geometrically complex anatomy are common within most contemporary head and neck radiotherapy treatment plans. The flexible nature of the spine connecting the head to the body leads to increasing positioning uncertainty with more inferior disease sites in the lower neck. No current mechanical solution exists which can independently adjust the head from the body to achieve proper positioning in these lower neck regions. In this study a new metal-free positioning system is developed for independent mechanical positioning of the head in a clinically usable design.
Methods: We introduce an independent, accessory mini-couch for the head with six degrees of freedom made from radio-compatible materials, including 3D-printed components. The motion accuracy and reproducibility are investigated by comparing programmed motion paths to achieved motion paths as measured by an optical measurement system. Compatibility with conventional treatment and imaging devices are investigated by comparing the measured computed tomography (CT) Hounsfield Units (HU) on radiographical scans to accepted values for cortical bone at diagnostic energies.
Results: The mini-couch was constructed using a combination of 3D-printed, laser cut, and off-the shelf components. Couch motion was achieved using a series of sliding linkages connected by long drivetrains to distant stepper motors. When moved over a series of random positions similar to typical setup errors, the prototype device had acceptable positioning accuracy. All components of the device within 30 cm of isocenter had measured HU values of less than 2700 of cortical bone at diagnostic energies (50 keV).
Conclusion: This feasibility study demonstrates sufficient clinical compatibility and positioning accuracy to be used for further patient studies investigating improvements in lower neck positioning independent from head positioning, which was never accomplished in automatic manner mainly due to lack of tools.
Funding Support, Disclosures, and Conflict of Interest: This work was funded by the School of Engineering and Quest for Innovation Commercialization Fund at Virginia Commonwealth University.
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