Ashrafkhani Behnam, Tabesh Armin, Tamsen Fredrik, Goodarzi Aaron A, Tondel Martin, Thompson Robert Ian, Wieser Michael E
Department of Physics and Astronomy, University of Calgary, Calgary, Canada.
Department of Surgical Sciences, Uppsala University, Uppsala, Sweden.
Sci Rep. 2025 Aug 9;15(1):29149. doi: 10.1038/s41598-025-15168-5.
Estimating the postmortem interval (PMI)-the time since death-remains a longstanding challenge in forensic and biological sciences due to the complex influence of environmental and physiological variables. Here, we present a novel computational framework that leverages the physical principles of radioactive decay to estimate PMI using the relative isotope abundances of radon progeny ([Formula: see text], [Formula: see text], and [Formula: see text]) in biological tissue. Our approach models the decay chain of inhaled [Formula: see text] and solves the associated system of differential equations to determine PMI based on isotope ratio dynamics. A key innovation is the use of paired measurements taken at two postmortem time points to capture the time-derivative of the decay curve, enhancing solution uniqueness, reducing dependence on prior exposure history, therefore minimizing error. Monte Carlo simulations were employed to assess model performance. If validated empirically, this approach lays the groundwork for a physics-based method for PMI estimation with potential applications in forensic science and radiation biology.
估计死后间隔时间（PMI）——即死亡后的时间——由于环境和生理变量的复杂影响，在法医学和生物科学领域仍然是一个长期存在的挑战。在此，我们提出了一种新颖的计算框架，该框架利用放射性衰变的物理原理，通过生物组织中氡子体（[公式：见正文]、[公式：见正文]和[公式：见正文]）的相对同位素丰度来估计PMI。我们的方法对吸入的[公式：见正文]的衰变链进行建模，并求解相关的微分方程组，以根据同位素比率动态确定PMI。一个关键的创新点是在两个死后时间点进行配对测量，以捕捉衰变曲线的时间导数，增强解的唯一性，减少对先前暴露历史的依赖，从而将误差降至最低。采用蒙特卡罗模拟来评估模型性能。如果经过实证验证，这种方法为基于物理的PMI估计方法奠定了基础，在法医学和辐射生物学中具有潜在应用。
