发表机构
Quantum Matter Lab, Department of Physics, College of Science, University of Tehran; Department of Atomic and Molecular Physics, Faculty of Physics, Alzahra University（德黑兰大学理学院物理系量子物质实验室; 阿尔扎哈拉大学物理学院原子与分子物理系）
机构由 AI 辅助整理，请以论文原文为准。AI 中文总结
针对乳腺癌检测，提出三重德拜介电模型及多层ADE FDTD仿真，显著提升太赫兹反射拟合精度（RMSE降至0.0199），并揭示含水量相关的时间与偏振对比机制。
AI 中文摘要
太赫兹（THz）成像因其对组织含水量的内在敏感性，已成为一种有前景的用于乳腺癌评估的非电离成像模态。然而，现有的生物组织介电描述大多局限于单德拜或双德拜模型，无法捕捉控制宽带太赫兹色散和吸收的多尺度弛豫动力学，从而限制了对反射脉冲的定量解释。本文开发了一种基于物理的三重德拜介电框架，用于定量预测宽带太赫兹-组织相互作用。所提出的模型明确包含了三个物理上不同的弛豫过程，分别与自由水旋转动力学、结合水弛豫（τ₂）以及超快界面/大分子极化（τ₃）相关。模型参数通过对从已发表的离体人乳腺组织太赫兹时域光谱测量中数字化得到的实验折射率数据进行非线性最小二乘拟合获得。与传统的德拜公式相比，所提出的模型显著提高了拟合精度，将均方根误差从0.7773（单德拜）和0.2976（双德拜）降低到三重德拜模型的仅0.0199。对真实多层乳腺结构的全波FDTD ADE仿真进一步表明，反射太赫兹脉冲通过可重现的时间特征编码组织含水量，包括恶性组织中反射振幅增加、脉冲到达延迟以及波形展宽增强。偏振和角度分辨的菲涅耳分析进一步表明，含水量依赖的伪布鲁斯特最小值通过选择性地抑制来自低含水量正常组织和脂肪组织的反射，提供了额外的对比机制。
英文摘要
Terahertz (THz) imaging has emerged as a promising non-ionizing modality for breast cancer assessment owing to its intrinsic sensitivity to tissue hydration. However, existing dielectric descriptions of biological tissue, largely restricted to single- or double-Debye models, fail to capture the multiscale relaxation dynamics governing broadband THz dispersion and absorption, thereby limiting the quantitative interpretation of reflected pulse signatures.Here, a physics based triple Debye dielectric framework is developed to quantitatively predict broadband THz-tissue interactions. The proposed model explicitly incorporates three physically distinct relaxation processes associated with free-water rotational dynamics, bound-water relaxation (τ_2), and ultrafast interfacial/macromolecular polarization (τ_3). Model parameters are obtained by nonlinear least-squares fitting to experimentally measured refractive-index data digitized from published THz time-domain spectroscopy measurements of ex vivo human breast tissue. Compared with conventional Debye formulations, the proposed model substantially improves the fitting accuracy, reducing the root-mean-square error from 0.7773 (single Debye) and 0.2976 (double Debye) to only 0.0199 for the triple-Debye model. Fullwave FDTD ADE simulations of realistic multilayer breast structures further demonstrate that reflected THz pulses encode tissue hydration through reproducible temporal signatures, including increased reflection amplitude, delayed pulse arrival, and enhanced waveform broadening in malignant tissue. Polarization and angle resolved Fresnel analysis further indicates that hydration-dependent pseudo-Brewster minima provide an additional contrast mechanism by selectively suppressing reflections from low hydration normal and adipose tissues.
