Date Approved
7-31-2024
Graduate Degree Type
Project
Degree Name
Medical Dosimetry (M.S.)
Degree Program
Health Professions
First Advisor
George Arnould
Academic Year
2023/2024
Abstract
Abstract
Introduction
Lung cancer remains the leading cause of cancer incidence and mortality worldwide. Advances in stereotactic body radiation therapy have demonstrated survival rates comparable to surgery, however, they come with a higher risk of developing radiation pneumonitis. The aim of this study was to explore the possibility of minimizing the risk of lung toxicities after stereotactic body radiation therapy to lung tumors with the use of functional lung planning and flattening filter free beams.
Materials and Methods
This retrospective study analyzed treatment planning data from ten patients previously treated with SBRT for inoperable lung tumors. Functional lung volumes were defined as low, mid, and high functioning regions and delineated from PET scans using a 50%, 70%, and 90% maximum pixel value threshold segmentation approach. All patients had treatment planning completed for functional planning with flattening filter free beams, functional planning with 6MV beams, anatomical planning with flattening filter free beams, and anatomical planning with 6MV beams. The plans were evaluated based on beam on time, modulation, conformity index (CI), gradient index (GI), and lung dose-volume metrics (V5, V12.5, V20, and mean lung dose).
Results
The study found that FFF beams significantly reduced beam on time and lug doses (V5, V12.5, and V20) compared to 6X beams. Functional lung planning alone reduced mean lung dose and V5Gy dose to mid and high functional lung volumes but did not significantly impact the overall plan quality. The combination of FFF beams and functional lung planning did not show a significant interaction in reducing lung doses compared to using each technique independently.
Conclusions
The findings indicate that while functional lung planning and FFF beams have the potential to lower lung doses, their combination does not provide additional benefits over using either technique alone. Additionally, it is important to investigate the potential advantages of these techniques for treating multiple-target lung tumors with SBRT.
ScholarWorks Citation
Gucwa, Addison, "A clinical comparison with the flattening free filter technique for lung stereotactic body radiotherapy using functional lung planning" (2024). Culminating Experience Projects. 477.
https://scholarworks.gvsu.edu/gradprojects/477
