Frequency Domain Inverse-MC Simulation For The Optical Property Reconstruction Of Cervical Tissue

Accurate measurement of tissue optical parameters is a very significant field in tissue optics. Researches on the biological tissue optical properties are the precondition of light applications in the foundation research and clinical applications in medical field, which can offer vital guidance to laser's clinic application. But how to describe the transmission of the diffuse photon in the thin tissue with complex structure in mathematical language, in particular, the choice of algorithm for inversal construction of the optical parameters from the surface measurement data of this complex structure still not been completely resolved. A method for rapid reconstruction of optical properties, such as the absorption and scattering properties of turbid media, is introduced in this dissertation. In the paper, the core content is noninvasive measurement of the optical parameters for the cervical tissue in frequency domain system. First, we introduced the theory of optical transmission in tissue, then, select the model and construction algorithm according cervical tissue shape, focus on the cervical tissue border signal processing and frequency-domain signal extraction methods; Finally, selecting a new type of algorithm-perturbation Monte Carlo method to determine tissue optical parameters and from two aspects - the simulation and experimention to certify the effective of this algorithm. Specifically including:1. The theoretical framework of tissue optics was described completely and systematically. such as the optical parameters describing the interaction between light and tissues,the theories for describing light transport in tissues2. According to the physical shape of cervical tissue, a hollow cylinder is seleceted as the simulation model. The amplitude and shape of the photon density wave have been obtained from the Monte Carlo simulation by means of the boundary treatment and time-to-frequency conversion.3. By combining the Perturbation Monte Carlo method and the Levenberg-Marqurdt method, the absorption coefficient has been reconstructed accurately and fastly. In the single layer model, absorption coefficient is succefully reconstructed from the amplitude and phase; the robustness, accuracy, and precision are also evaluated on simulated models; simultaneous reconstruction of absorption coefficient and scattering coefficient is investigated. In the two-layered model, the reconstruction is also investigated. 4. Produced a cervical tissue model with india ink and Intralipid-10% solution for experiments, and get the amplitude and phase data from the time-resolved measurement, then input them to the reconstruction algorithm to get the absorption coefficient values and the error, and analysis the reason of the error, the result show that the reconstruction algorithm is reasonable. It laid a good foundation for future study.