SUMMARY

Our research group has developed a computational model to predict heat production and dissipation in tissue when a tumor containing optically-tunable gold nanoparticles such as nanoshells or nanorods is illuminated with near infrared (NIR) laser. However, the validity of the model still needs to be established by experiments before its wide use for various future clinical applications based on the use of NIR laser and gold nanoshells or nanorods. One of the possible ways to validate the model is through the heat measurements within a phantom made with tissue-equivalent heat-sensitive gel. Currently, there are a few recipes available for this type of gel and majority of them use severely toxic ingredients. However, none of them seems to perfectly serve the current purposes. Therefore, the primary goal of this thesis work was to develop and characterize two new types of heat-sensitive gels, using relatively non-toxic substances, which are suitable for the in-phantom validation of the aforementioned computational model. Specifically, two novel agar based phantoms with slight compositional differences containing bovine serum albumin (BSA) were developed and characterized. Note BSA is a heat sensitive protein that will undergo denaturing and leave behind an optical density change at the areas where temperature exceeds 70 °C. The basic optical response of these phantoms at 808 nm NIR light was determined to test their equivalency to human tissue. Thermal damage to the phantoms was quantified by heating them to specific temperatures and obtaining calibration curves to relate temperature and R2 (R2 = 1/T2) relaxation rates. The phantoms were scanned with magnetic resonance imaging (MRI) to obtain T2 values. In this presentation, the results and findings from this thesis work will be described in detail.