Date Approved
7-30-2025
Graduate Degree Type
Project
Degree Name
Medical Dosimetry (M.S.)
Degree Program
Health Professions
First Advisor
Mubin Shaikh
Academic Year
2024/2025
Abstract
Purpose: This study aimed to evaluate the dosimetric and efficiency impacts of different photon beam energies—6MV, 6 flattening filter free (FFF), 10MV, and 10FFF—on volumetric modulated arc therapy (VMAT) plans for endometrial cancer, with attention to target coverage, organ at risk (OAR) sparing, and treatment efficiency.
Methods: A retrospective analysis was conducted on 25 patients with post-hysterectomy endometrial cancer. Each patient received four VMAT plans with varying energies. Planning metrics assessed included planning target volume (PTV) dose maximum (Dmax), conformity index (CI), heterogeneity index (HI), OAR doses (bladder, bowel, rectum), and total monitor units (MU). Correlations were drawn between patient separation and dosimetric outcomes.
Results: 6FFF plans produced the highest PTV Dmax, MU, and slightly higher rectal doses. 10FFF plans had the highest conformity and superior bowel sparing, though with elevated MU. 10MV plans yielded the lowest rectal doses and had slightly lower conformity. Statistically significant associations were found between patient lateral-to-anteroposterior (AP) separation ratios and variations in HI, bladder, and rectum doses. FFF beams required more MUs yet may offer reduced treatment times due to higher dose rates.
Conclusions: All beam energies yielded clinically acceptable plans; however, dosimetric performance varied by modality and patient anatomy. Beam selection should be individualized, considering both anatomical factors and clinical goals.
ScholarWorks Citation
DePas, Madisin M., "Dosimetric Comparisons of 6MV, 6FFF, 10MV, and 10FFF on VMAT Planning in Patients with Endometrial Cancer" (2025). Culminating Experience Projects. 608.
https://scholarworks.gvsu.edu/gradprojects/608
