POSSIBILITIES OF DETERMINING THE TIME SINCE DEATH USING THE METHODS OF MULTIDIMENSIONAL POLARIZATION AND AUTOFLUORESCENCE MICROSCOPY OF THE HUMAN VITREOUS BODY

Abstract

Given the current state of affairs in practical forensic medicine and the considerable amount of scientific research on the exact determination of the postmortem interval, we conclude that the determination of the time since death is a key problem, but not yet sufficiently solved. Accurately estimating the time since death is critical to many investigations and remains one of the most challenging variables.
 Carrying out an accurate determination of the time of death is important using a complex approach, since solving this problem requires taking into account all aspects of thanatogenesis, the influence of environmental factors and other circumstances of the case. This leads to an increase in the popularity of global research involving the latest advances in medicine, chemistry, physics and forensics. The use of comprehensive research allows us to come closer to establishing the approximate range of the time since death.
 Aim of the work. Development of a complex of objective forensic medical criteria to improve the possibilities of accurately determining the time since death over a long period of time by using multidimensional polarization and autofluorescence microscopy of the human vitreous body.
 Materials and methods. The object of the study were samples of human vitreous body, deceased from cardiovascular pathology, with a known time of death.
 The following research methods were used: Mueller-matrix mapping, microscopic polarization tomography, spectral-selective laser-induced autofluorescence, statistical and wavelet analysis of the results of experimental data.
 Results. The significant effectiveness of the proposed methods in accurately determining the time of death has been demonstrated. In particular, polarization microscopic tomography using scale-selective wavelet analysis of distributions of linear birefringence of human vitreousbody layers provides a diagnostic range for determining the time since death of 36 hours with an accuracy of up to 14-16 minutes, which was not achieved by any of the existing laser polarization methods. At the same time, the combination of polarization tomography of biological tissues with spectral-selective laser fluorescence microscopy – one of the most sensitive methods,due to the assessment of the concentration parameters of molecules, opens a new window of possibilities and establishing the time since death and diagnosis of various pathological conditions. The obtained results confirm the effectiveness of this technique and show the diagnostic range of determining the time since death of 36 hours with an accuracy of up to 15-20 minutes.
 Conclusions. The innovative approach proposed in the scientific study makes a significant contribution to the development of forensic medical examination, providing more accurate and reliable identification of the time since death, which can be useful in criminal investigations and in solving other forensic tasks.