Monte Carlo Dose Calculations for Permanent Breast Seed Implant Brachytherapy

It appears your Web browser is not configured to display PDF files. Download adobe Acrobat or click here to download the PDF file.

Click here to download the PDF file.


Deering, Stephen




To investigate the use of patient-specific (rather than water-based) models for permanent breast seed implant (PBSI) brachytherapy, a retrospective study of 35 PBSI patients is performed. Virtual detailed-tissue patient models are created and overlaid with Pd-103 seed geometries, allowing for simulations with egs_brachy, a new Monte Carlo code.

Considerable discrepancies in dose distributions are demonstrated. Target dose metrics are 4-26\% higher using TG43 assumptions, skin metrics are underestimated by up to 66.5\%, and large disparities are observed in heart, lung, and rib doses. The sensitivity of dose distributions to assumptions in model creation is examined. Individualized adipose-gland segmentation thresholds and realistic seed orientations are shown to be important for accurate modeling. Radioprotective lead shielding has a negligible impact on skin dose.

This thesis demonstrates the importance of detailed patient modeling for PBSI brachytherapy, illustrating the shortcomings of TG43-based simulations and contributing to the future clinical implementation of model-based dose calculation algorithms.


Physics - Radiation




Carleton University

Thesis Degree Name: 

Master of Science: 

Thesis Degree Level: 


Thesis Degree Discipline: 


Parent Collection: 

Theses and Dissertations

Items in CURVE are protected by copyright, with all rights reserved, unless otherwise indicated. They are made available with permission from the author(s).