Date of Award

January 2026

Document Type

Thesis

Degree Name

Medical Doctor (MD)

Department

Medicine

First Advisor

Christopher J. Tien

Abstract

Traditional external-beam radiation therapy used to treat cervical cancer can damage sensitive organs in the pelvis, making brachytherapy a key therapeutic option for patients. This study introduces a novel brachytherapy applicator consisting of six tungsten shielding rods surrounding a central channel for a radioactive source. These rods can be inserted or removed to modulate the radiation distribution from the source and preserve pelvic organs near the tumor. The software Tool for Particle Simulation (TOPAS) was used to run Monte Carlo simulations of the applicator in various shielding rod configurations. We show that the shielding rods can effectively modulate the radiation from the source and show that our design results in a statistically significant decrease in radiation delivery outside the region-of-interest for a specific shielding rod configuration. In addition, we propose a novel method for optimizing over the distribution of shielding rods and show that this method proposes reasonable shielding rod configurations for both single- and two-applicator scenarios. These results serve as a proof-of-concept that our design may provide improved radiation distributions to brachytherapy patients and may be amenable to inverse-planning methods in the future.

Comments

This thesis is restricted to Yale network users only. It will be made publicly available on 06/01/2029

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