Date of Award

2009

Degree Type

Thesis

Degree Name

Master of Science (MSc)

Department

Biomedical Physics

First Advisor

Carl Kumaradas

Second Advisor

William Whelan

Abstract

Thermal dose models are metrics that quantify thermal damage in tissues based on the temperature and the time of exposure. The validity and accuracy of one of the commonly used models (CEM₄₃) for high temperature thermal therapy applications (50-90 degree Celcius) is questionable. It was found to over-estimate the accumulation of thermal damage for high-temperature applications. A new CEM₄₃ dose model based on Arrhenius type Vogel-Tammann-Fulcher equation using published data is introduced in this work. The new dose values for the same damage threshold that was produced at different in-vivo skin experiments were in the same order of magnitude, while the current dose values were 2 orders of magnitude different. The new dose values for same damage threshold in 6 lessions in ex-vivo liver experiments were more consistent than the current dose values. Computer simulations of laser interstitial thermal therapy showed that the current model usually predicts bigger volume than the new model does. The deviation in damaged volume prediction can be significant. The contribution of this work is introducing methods that can lead to more robust thermal dosimetry which will result in improved therapy modelling, monitoring and control.