Measuring tissue heat penetration by scattered light measurements

Background and Objectives: The monitoring of tissue morphological changes during clinical procedure such as laser thermotherapy, laser hair removal and others is important in order to prevent damage to healthy tissue. An optical system and method for the assessment of real time in vivo tissue morphological changes is proposed. Materials and Methods: We used ex vivo chicken breast as tissue samples. The samples were irradiated by CO₂ laser to create thermal structural changes. The optical properties of the tissue samples were measured using an integrating sphere method. We measured the tissue heat penetration and the scattered light from the tissue and compared the results to Monte-Carlo simulation. Results: Thermal interaction causes structural changes in the tissue. Therefore changing (increasing) the scattering properties of the tissue. We relate the structural changes to the scattered light pattern and proposed a method for controlling the thermal interaction. Conclusion: It is possible to design a real time in vivo controlling system for laser tissue thermal interaction that utilizes the changes in the scattered light pattern.