Preliminary Study On Skin Equivalent Optical Phantom

The photonics and its technology have been widely applied in the fields of bioscience and medical science. Its development and its achievements will much more help to early diagnosis of cardiovascular disease and cancer, so as to improve human survival conditions and survival quality. The development of photonics requires development of theoretical models and experimental procedures, as well as tissue equivalent phantoms. Our aim is to develop a stable and reproducible phantom whose optical properties can be predetermined and match those of human skin tissue at the selected wavelength (λ=1310nm). This skin equivalent optical phantom could be effectively applied in various research fields including non-invasive blood glucose sensing. In the work, preliminary study of the phantom and application of the phantom in non-invasive blood glucose sensing both have been discussed.In the first, an overview of tissue-simulating phantoms'compositions and properties is outlined, by separating matrix, scattering, and absorbing materials, and discussing the benefits and weaknesses in each category. Subsequently, a skin equivalent optical phantom is presented and characterized. The base material of the phantom is gelatin, in which TiO2 particles and Copper sulfate (CuSO4) are embedded as scatters and absorbers respectively. Optimize and standardize the phantom preparation procedures through qualitative experimental study. The optical coefficients of the samples, i.e., absorption coefficientsμa and reduced scattering coefficientsμs', are determined by using a double-integrating-sphere system. The results obtained in preparation reproducibility experiment show that the standard deviation value of the absorption coefficients is less than 0.98% of its average value, and the standard deviation value of the reduced scattering coefficients is less than 0.53% of its average value. The preparation reproducibility is a great satisfaction. Conclude the optical coefficients predetermination equation according to theoretical analysis and quantitative experimental research. The results obtained in verification experiment show that the relative error of the absorption coefficient is about 11.1%, and the relative error of the reduced scattering coefficient is less than 2%, which means that an excellent agreement is obtained between experiment measurements and the predetermined value. The optical coefficients predetermination equation is more accurate for the predetermination of the reduced scattering coefficients.In the second, systematically analyze the main research contents in non-invasive blood glucose sensing. Investigate the influence of glucose concentration upon the optical coefficients of the phantoms by theoretical analysis and experimental research. The experimental results presented in this paper are in accordance with the theoretical analysis on the change trend. The relative change of the reduced scattering coefficient of the phantoms (δμs') is 0.645%mM-1, which is close to that in the in-vivo experiment by Maier et al.(δμs'=0.583%mM-1). Furthermore, the Monte Carlo simulation results in homogeneous and heterogeneous phantoms show that glucose concentration has a significant influence upon the transport of light in phantoms. And by the statistical analysis of the diffuse reflectance light, information about glucose in the phantoms can be extracted.