Doctor of Philosophy (PhD)
Physics and Astronomy
Despite advancements in cancer therapy, certain indications continue to have a poor prognosis, including cancers of the thorax. Existing methods for treating moving tumors with carbon ions have shown promise, but require technologically complex facilities and still have inherent limitations to mitigating tumor motion. The goal of this dissertation was to develop and test a safe, portable, and modular motion-synchronized dose delivery system (M-DDS) and its peripheral components as a framework for studying motion mitigation with ion beams.
We designed and integrated a motion-synchronized radiotherapy approach, called multi-phase 4D delivery (MP4D), as modular units of a clinical dose delivery system. The MP4D approach was integrated into a research facility and the facility was redesigned for developing and testing new cancer therapy technologies. We performed a comprehensive risk assessment for the M-DDS and validated the performance of the MP4D approach experimentally. Finally, we compared MP4D to other delivery strategies in terms of dosimetric quality and projected therapeutic outcomes.
The prototype system was implemented and characterized at GSI and CNAO. The functionality and performance were confirmed through a series of tests. Validations revealed that MP4D produces quantitatively superior dosimetric quality and projected therapeutic outcomes. Additionally, we determined that the MP4D dose delivery strategy compensated for heterogeneous anatomical motion with minimal dose distribution degradations. Our safety analysis revealed several risks that are unique to MP4D; appropriate solutions were implemented and tested.
The major findings of this study are that the MP4D approach delivered conformal, motion-synchronized beams with acceptable performance, dosimetric quality, safety, and projected therapeutic outcomes. We demonstrated that MP4D may become a suitable strategy for conformal, motion mitigation in clinical radiotherapy. The modular design of the M-DDS allows for integration into a variety of facilities, and the MP4D methods presented can be utilized at any ion therapy center that operates with a similar delivery system. The generalized and modular design of the M-DDS provides a framework for testing a variety of motion mitigation and other therapy approaches. This work, taken together, provides a comprehensive pre-clinical study on the modular, motion-synchronized dose delivery system for delivering conformal dose distributions to moving targets.
Lis, Michelle Jennifer, "A Generalized, Modular Approach to Treating Moving Tumors with Ion Beams" (2021). LSU Doctoral Dissertations. 5582.