Study On The Optical-Thermal Response Of Nasopharyngeal Tissue

Based on the physical mechanism of optical-thermal response of biotissue during laser irradiation, the dose of laser and the distribution of the temperature field of nasopharyngeal tissue were studied in this thesis. This can provide theoretic and experiment foundation for choosing the light dose and obtaining the temperature distribution in tissue during diagnosing and localization of tumor.Firstly, the transfers characteristic of laser and the temperature distribution in the nasopharynx tissue induced under the irradiation of laser were simulated by the Monte Carlo model and ID Pennes' bioheat transfer equation respectively.Secondly, the experiment project presented in this thesis offer a measurement to detect the temperature distribution in the albumen phantom in vivo and several mammalian tissues such as porcine nasopharynx tissue in vitro. The changing of temperature was induced under the irradiation of argon ion laser emitting at the wavelength of 488nm and 514.5nm, respectively. Furthermore, the dependence of measuring position, irradiation time and irradiation energy density, as well as wavelength on the temperature distribution was studied in detail.Simulation results and experimental results show that the temperature distributions in the porcine nasopharynx tissue were significantly affected by measuring position and the energy density and wavelength of irradiation laser. The experiment results show that safe dose of porcine nasopharynx tissue during the irradiation of argon ion laser at the wavelength of 488nm and 514.5nm is 1.85W/cm2 and 1.72 W/cm2 .respectively.The results obtained of this thesis can contribute to further investigation and several theories foundation and useful experiment data in the optothermal biotissue response during laser irradiation and clinical laser applications such as laser dynamically diagnosing nasopharyngeal carcinoma.