The potential of raman spectroscopy as a monitoring tool for thermal therapy

Matthew Rodriques

doi:10.32920/ryerson.14657466.v1

Abstract

Laser Interstitial thermal Therapy (LITT) is a minimally invasive technique for treating localized solid tumors through heating with light. LITT is not routinely employed in a clincal setting due to difficulties in real-time monitoring of tissue heating. This work investigates the feasibility of Raman Spectroscopy (RS) to monitor thermal therapies. RS has the ability to detect changes in the seconcary structure of proteins, and may prove useful as an indicator of tissue coagulation in real-time during thermal therapy. Tissue equivalent albumen phantoms were heated in a water bath and bovine muscle samples where heated in a water bath and through laser photocoagulation. Raman spectra were acquired after heating and increases in the overall Raman intensity and shifts in major band locations were observed after heating. Correlations between Raman intensity and thermal dose were also observed. These results indicate that RS may be employable as a real-time monitoring tool for LITT.

Highlights

Ll- The Raman Effect Scattering of photons by atoms or molecules occurs through either elastic or inelastic scattering
As with the albumen group and many other proteins, the overall intensity changes and shifts seen in the Raman bands of collagen I are believed to be due to changes in the 2° AA conformation and the 3o folding structure of the protein constituents as a result of denaturation caused by heating
3.1 - Tissue Equivalent Albumen Phantoms Albumen phantoms were heated to target temperatures of 45, 55, 64 and 75°C in a water bath held at 75°C, and allowed to cool to approximately 22°C

Summary

- Introduction

Ll- The Raman Effect Scattering of photons by atoms or molecules occurs through either elastic or inelastic scattering. As with the albumen group and many other proteins, the overall intensity changes and shifts seen in the Raman bands of collagen I are believed to be due to changes in the 2° AA conformation and the 3o folding structure of the protein constituents as a result of denaturation caused by heating. The middle region (white) of figure 1-7 is known as the coagulation zone, with temperatures ranging anywhere from 60°C to 100°C In this region, a whitening of the tissue can be observed by the naked eye due to protein denaturation resulting from alterations in 2o and 3o protein structures. The work in this thesis investigates the potential of Raman Spectroscopy to identify changes in tissue properties resulting from thermal coagulation of tissue equivalent phantoms and bovine muscle tissue samples.

- Materials and Methods

- Results and Discussion

2.65 X 10'J

-Appendix

- References