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Measuring the Effects of Temperature on Optical Propagation in Heated Tissues Using Point Radiance Spectroscopy

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posted on 24.05.2021, 10:38 authored by Radoslaw Sadowski
Laser interstitial thermal therapy (LITT) is a minimally invasive therapy in which light is delivered using optical fibers inserted into tissue to treat malignant tumours. Heating tissue above 55°C causes tissue coagulation, creating non-viable tissue. Previous work has demonstrated that radiance measurements are sensitive to heat-induced changes in tissue optical properties. This study investigates the use of radiance measurements to differentiate permanent temperature-induced changes in optical propagation, which reflect thermal damage, from any transient changes in optical propagation. Experiments in water using our white-light point radiance spectroscopy (PRS) technique demonstrate that PRS is sensitive to detect optical absorption and temperature-dependence in the optical absorption of water, and a change in the acceptance cone with temperature. Experimental results using PRS in heated ex vivo porcine tissue show that the optical signal mainly represents permanent thermal damage and only a small part of the signal represent a temperature-dependent change due to water.

History

Language

eng

Degree

Master of Science

Program

Biomedical Physics

Granting Institution

Ryerson University

LAC Thesis Type

Thesis

Thesis Advisor

Carl Kumaradas Robert A. Weersink William M. Whelan