Date Approved
8-4-2025
Graduate Degree Type
Project
Degree Name
Medical Dosimetry (M.S.)
Degree Program
Allied Health Sciences
First Advisor
Yi Le
Academic Year
2024/2025
Abstract
Abstract Purpose Rectal spacers are used in prostate cancer radiotherapy to reduce rectal dose and subsequent toxicity. This study aimed to directly compare the Barrigel hydrogel spacer and the BioProtect balloon spacer in terms of rectal dose reduction in the context of proton therapy. Methods A total of 30 prostate cancer cases treated at a single institution were retrospectively analyzed, evenly split between Barrigel and BioProtect arms (n=15 each). Each patient had both a prostateonly and a whole pelvis proton treatment plan created for this investigation. Dosimetric data were generated using uniform scanning and pencil beam scanning in RayStation 2023B. Prostate and rectal structures were contoured on MRI and CT, and dose-volume parameters (V70, V60, V50) were extracted for comparative analysis. Spacer volume and maximum anterior-posterior separation were also recorded. Statistical comparisons were performed using t-tests and MannWhitney U tests. Results BioProtect produced significantly greater prostate-rectum separation (18.3 ± 1.3 mm vs. 14.5 ± 2.9 mm) and larger spacer volumes (15.4 ± 1.7 cc vs. 9.9 ± 1.6 cc) than Barrigel. In pelvis plans, BioProtect reduced rectal V70 by 82%, V60 by 76%, and V50 by 74% compared to Barrigel (p< 0.001). In prostate-only plans, reductions were 60% for V60 and 52% for V50 (p< 0.01). Conclusion The BioProtect balloon spacer demonstrated superior and more consistent rectal dose sparing compared to Barrigel in proton therapy plans, suggesting potential for improved toxicity outcomes and quality of life.
ScholarWorks Citation
Arnold, Joseph, "Dosimetric comparison of BioProtect balloon and Barrigel hydrogel rectal spacers in proton therapy for prostate cancer" (2025). Culminating Experience Projects. 611.
https://scholarworks.gvsu.edu/gradprojects/611
