Program Information
An Innovative Rectal Repositioning Device for Radiotherapy Applications of Pelvic Cancer: Design Methodology and Simulation Studies
H Lavvafi 1,2*, S Parsai 3 , A Jahadakbar 1, A Tiwari 1 , M Elahinia 1 , V Devabhaktuni 1 , E Parsai 1 , (1) University of Toledo Medical Center, Toledo, OH, (2) Loyola University Medical Center, Maywood, IL (3) Cleveland Clinic Foundation, Cleveland, Ohio
Presentations
WE-RAM2-GePD-T-2 (Wednesday, August 2, 2017) 10:00 AM - 10:30 AM Room: Therapy ePoster Lounge
Purpose: Maximizing radiation dose to the tumor while sparing surrounding tissues is a necessity in designing radiotherapy treatment plans. Many clinics are utilizing SBRT of photon or proton radiotherapy in treating various cancer sites including prostate where sparing critical structures such as rectum are even more crucial. In treatment of prostate cancer, rectal overdose can lead to acute proctitis, potential late toxicities, chronic irritation, ulceration, bleeding, fistula or secondary cancer. This work addresses such problem by introducing an organ re-positioner device designed to physically displace the rectum away from the path of radiation beam with use of NiTi shape memory alloy. COMSOL simulation software was utilized to monitor the temperature profile of the device for safe implementation with the use of a circuit that was designed in order to induce the reversible NiTi actuation for rectal displacement in a controlled, reproducible and safe manner.
Methods: The organ re-positioner’s actuation properties and temperature profile was simulated using COMSOL simulation software package and the prototype’s actuation, temperature and displacement was tested with an experimental design which employed a Power Supply, Controller Board, Micro-Epsilon industry standard laser sensor, Control Desk and MATLAB Software.
Results: The prototype temperature profile was modeled in COMSOL and the results were compared to the experimental data that was obtained from the rectal re-positioning device prototype. The heat dissipation and respective temperature profile of the device’s components and the measured displacement values were agreeable to theoretical modeled parameters and safe implementation of the device was carefully assessed.
Conclusion: The rectal displacement showed a correlation between the displacement and the Nitinol’s temperature. A design formalism detailing the shape and displacement of actuator has been developed correlating with current modulation. The study finds the novel organ re-positioner a promising, safe and affordable tool for advanced radiotherapy of the pelvis.
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