Modelling of glucose level in living biological tissues by using optics de-polarization relationship

Studies on the development of glucose-level monitoring devices that determine the level of sugar in non-invasively which is miniatured and portable, suitable for hospital and home using have begun in the 1980s and studies are still ongoing. However, until now, a reliable devices capable of high-accuracy measurements has not yet produced its place on the market and is not available for human use. Within the scope of this thesis, it is aimed to take the first step in order to eliminate this deficiency. There are a number of studies currently underway with diverse techniques and methods for the research and development of medical devices to enable the follow-up of diabetes in the beginning and the follow-up phase and the approaches that use classical optical methods have appeared in researches. Polarized light is known to increase sensitivity and detection capability of measurement systems. Today in the examination of biological tissues, for setting of medical diagnoses and it is now known to be used frequently in various applications (microscope, MR, etc.). Polarimetry is the name given to the polarized light turning power of optically active substances. The amount of rotation and direction (optical rotational power) is an important feature for qualitative and quantitative analysis and contains important information about the chemical, physical structure and density of the materials. In this thesis, no human experiment was performed in the first stage so by using optical design program, models were obtained which can best represent these tissues by using the optical parameters of the biological tissues obtained from various sources in the literatures. When the model was constructed, the main molecules forming the main structure of the cells were emphasized, but the cellular molecules which had little effect on the optical properties were not taken into account. The model is based on the upper and lower skin and main molecular component of blood such as density of hemoglobin, hemoglobin oxygen saturation rate and blood plasma amount. For this reason, the blood flow model used in this study effects of blood flow rate, other blood proteins, shape, orientation, temperature and density of other red blood cells have neglected. In this way, the simplest optical models of the tissues can be obtained. The absorbance, transmission, scattering, and refractive index values of biological tissues were determined and models were constructed. Then, the appropriate wavelength range for measuring glucose level was determined, and then the behavior of the four parameters determining the optical property in the determined wavelength range was investigated. The appropriate wavelength window for glucose measurement was thus determined and tested. Then, using these models and various analysis functions available in the optical design program, de-polarization information is measured, depending on the glucose ratio in the determined wavelength. Finally, a mathematical expression was obtained using the glucose ratio-polarization information variables. Thus, the mathematical equation makes it possible to predict the glucose ratio depending on the polarization information. In addition to all this, this thesis containing a useful information about designing and modeling optical components of optically active materials, using catalogs, defining and analyzing various analyzes, using optical design program, which is not widely used by users at present. In theoretically using the classical optic and polarimetric methods and with the help of a simulation program, the change of direction (hyperglycemia or hypoglycemia) with the abnormal changes in the blood sugar level is the main objective of this study. In this direction, the basic parameters that will determine the expected polarization deterioration in the light to be used are modeled on the basis of the information obtained from the literature (including the content) and transferred to the simulation program. An empirical mathematical equation expressing the knowledge of the change in the blood sugar ratio of the corruption in the polarization information is proposed through the simulation program. The proposed equation predicts the mean level of glucose in the modelled blood and mean error only 0.1% depending on the polarization information and has an almost linear relationship in the range of [80-110] mg / dl where blood glucose level is considered normal / healthy.