Award Date

5-15-2026

Degree Type

Doctoral Project

Degree Name

Doctor of Medical Physics (DMP)

Department

Health Physics and Diagnostic Sciences

First Committee Member

Steen Madsen

Second Committee Member

Cephas Mubata

Third Committee Member

Yu Kuang

Fourth Committee Member

Ryan Hecox

Fifth Committee Member

Sharon Jalene

Number of Pages

84

Abstract

Spatially fractionated radiation therapy (SFRT) using lattice radiotherapy (LRT) has emerged as a promising treatment technique for bulky, nonresectable tumors by delivering spatially heterogeneous dose distributions consisting of high-dose vertices embedded within lower-dose regions. Although early clinical experiences have demonstrated potential therapeutic benefit, widespread clinical implementation of LRT remains limited due to the absence of standardized treatment planning workflows, consistent optimization strategies, and clearly defined evaluation metrics for heterogeneous dose distributions. The objective of this study is to develop and evaluate a structured framework to support efficient, reproducible, and safe clinical implementation of LRT.

To address these challenges, a comprehensive planning workflow was developed and evaluated at St. George Cancer Center. An instance of the MAAS SFRTHelper tool was configured and integrated into the treatment planning process to facilitate automated lattice geometry generation. Retrospective LRT treatment plans were generated on previously treated patient datasets to investigate optimal lattice geometries and planning strategies. Generalized equivalent uniform dose (gEUD) optimization objectives were evaluated to determine appropriate optimizer settings for controlling valley dose while maintaining high-dose vertices within the target volume. A set of dosimetric evaluation parameters was established to assess plan quality in the presence of highly heterogeneous dose distributions. Additionally, potential failure modes associated with LRT planning and delivery were identified through workflow analysis to support the development of clinical safety safeguards.

The proposed framework enabled reproducible lattice geometry generation and provided a systematic approach for treatment planning and evaluation. The incorporation of standardized strategies and evaluation metrics improved planning consistency, while safety analysis identified key areas requiring verification during clinical implementation. These results show that integrating planning tools, standardized evaluation criteria, and safety processes can facilitate the practical and safe adoption of LRT within existing radiation oncology workflows.

Keywords

GRID; Lattice; Oncology; Physics; Radiation; SFRT

Disciplines

Health and Medical Physics | Medicine and Health Sciences | Physics

File Format

PDF

File Size

7700 KB

Degree Grantor

University of Nevada, Las Vegas

Language

English

Rights

IN COPYRIGHT. For more information about this rights statement, please visit http://rightsstatements.org/vocab/InC/1.0/

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