Physics Based Triple Debye Dielectric Modeling and Multi Layer ADE FDTD Simulation of Terahertz Pulse Reflection for Breast Cancer Detection
Abstract
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.
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BibTeX
@misc{choobini2026physics,
title = {{Physics Based Triple Debye Dielectric Modeling and Multi Layer ADE FDTD Simulation of Terahertz Pulse Reflection for Breast Cancer Detection}},
author = {Ali Asghar Molavi Choobini and Mehran Shahmansouri},
howpublished = {arXiv},
year = {2026},
month = sep,
doi = {10.48550/arxiv.2609.12701},
eprint = {2609.12701},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2609.12701},
}
RIS
TY - UNPB
TI - Physics Based Triple Debye Dielectric Modeling and Multi Layer ADE FDTD Simulation of Terahertz Pulse Reflection for Breast Cancer Detection
AU - Ali Asghar Molavi Choobini
AU - Mehran Shahmansouri
PY - 2026
DA - 2026/09/11
PB - arXiv
DO - 10.48550/arxiv.2609.12701
UR - https://arxiv.org/abs/2609.12701
AB - 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.
ER -