Program Information
A Novel Assisted Breath Hold System for Involuntary Breath Hold in Radiotherapy
M Ostyn1*, D Lee1, E Fields1, S Kim1, H Yoon2, J Lee3, T Kim1 , (1) Radiation Oncology, Virginia Commonwealth University, Richmond, VA, (2) Center for Materials Research, Norfolk State University, Norfolk, VA, (3) Radiation Oncology, Johns Hopkins University, Baltimore, MD
Presentations
TU-RPM-GePD-J(A)-3 (Tuesday, August 1, 2017) 3:45 PM - 4:15 PM Room: Joint Imaging-Therapy ePoster Lounge - A
Purpose: Breath-holds have become an effective method of reducing intrafraction motion in radiotherapy with advanced imaging techniques. Existing breath-hold control systems using spirometer-based measurement of respiratory motion are not sensitive to detect errant breathing motion and existing hardware is not compatible with magnetic resonance (MR) imaging. In this study, a new assisted breath-hold control system is developed which can detect errant breathing motion and can be used in MR-environments, while matching key performance metrics of existing assisted breath-hold control systems.
Methods: We developed a new system for assisted breath-hold involving a custom 3D-printed pneumatic valve integrated with an air handling system and is triggered by an external infrared respiratory motion surrogate tracking system. MR-compatibility was ensured and confirmed by noting the presence or absence of metal artifacts on a series of common computed tomography (CT) and MR imaging scans. We also demonstrated the feasibility of the method by evaluating efficacy of breath-hold control and sensitivity to errant breathing motion using the respiratory monitoring system. System response time was measured with a high-speed video recording.
Results: The assisted breath-hold system was developed using 3D-printing technique and combined with the respiratory tracking system. Breath-hold could be initiated and maintained by the air handling system with errant breathing motion detectable by observing surrogate motion during breath-hold with the infrared camera. As intended, no metal artifacts were visible on either the CT images or on the MR scans. The system was able to satisfactorily arrest respiratory airflow with a competitive response time.
Conclusion: This foundational work demonstrates the efficacy of a new assisted breath-hold system with MR-compatibility. This system shows promise at reducing errant breathing compared with similar existing systems while still matching their desirable characteristics, and also allows radiation oncologists to utilize assisted breath-hold during MR imaging for better soft tissue differentiation.
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