Defense Date
2026
Document Type
Thesis
Degree Name
Master of Science
Department
Radiation Oncology
First Advisor
Dr. Siyong Kim
Abstract
Ultra-high dose rate (FLASH) radiotherapy has demonstrated promising normal tissue sparing in preclinical studies; however, the lack of standardized dosimetry, commissioning, and quality assurance (QA) methodologies remains a major barrier to its reproducible and safe implementation. In particular, conventional clinical commissioning and QA protocols are not directly applicable at FLASH dose rates due to challenges associated with detector response, dose-per-pulse effects, and beam control limitations.
This thesis presents the commissioning of a converted Varian 21EX linear accelerator for electron FLASH operation within the Division of Medical Physics at the Virginia Commonwealth University (VCU) Department of Radiation Oncology. Comprehensive beam characterization was performed for ultra-high dose rate electron delivery, including measurements of depth-dose curves, beam profiles, output, and dose stability. Dosimetric measurements were conducted using a combination of plastic scintillation detection, solid-state diamond detection, and radiochromic film to address the limitations of individual detectors at ultra-high dose rates.
Based on the commissioning results, a practical and reproducible QA protocol was developed to support future preclinical FLASH experiments involving small-animal irradiation. The proposed QA framework emphasizes beam reproducibility, safety, and operational efficiency rather than conventional clinical tolerances, reflecting the unique requirements of preclinical FLASH research. This work provides a structured approach for commissioning and maintaining a research linear accelerator for FLASH applications and contributes to the ongoing development of standardized physics methodologies for preclinical FLASH radiotherapy.
Rights
© The Author
Is Part Of
VCU University Archives
Is Part Of
VCU Theses and Dissertations
Date of Submission
5-3-2026