Polarization optical imaging can be used to characterize anisotropy in biological tissue microstructures and has been demonstrated to be a powerful tool for clinical diagnosis. However, the approach is limited by an inability to image targets deeper than $\sim 1\mathrm{mm}$ due to strong optical scattering in biological tissues. As such, we propose a novel polarization microwave-induced thermoacoustic imaging (P-MTAI) technique to noninvasively detect variations in deep tissue by exploiting the thermoacoustic signals induced by four pulsed microwaves of varying polarization orientations. The proposed P-MTAI method overcomes the penetration limits of conventional polarization optical imaging and provides submillimeter resolution over depths of several centimeters. As part of the paper, the structural characteristics of tissues were quantified using a new parameter, the degree of microwave absorption anisotropy. P-MTAI was also applied to the noninvasive detection of morphological changes in cardiomyocytes as they transitioned from ordered to disordered states, providing a potential indication of myocardial infarction.

中文翻译：

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偏振微波诱导热声成像用于定量表征深部生物组织微结构

偏振光学成像可用于表征生物组织微结构的各向异性，并已被证明是临床诊断的有力工具。然而，该方法受限于无法将目标成像更深于$～1\mathrm{毫米}$由于生物组织中的强光散射。因此，我们提出了一种新的偏振微波诱导热声成像 (P-MTAI) 技术，通过利用由不同偏振方向的四个脉冲微波诱导的热声信号来无创地检测深层组织的变化。所提出的 P-MTAI 方法克服了传统偏振光学成像的穿透限制，并在几厘米的深度上提供亚毫米分辨率。作为论文的一部分，组织的结构特征使用一个新的参数——微波吸收各向异性的程度来量化。P-MTAI 还应用于无创检测心肌细胞从有序状态转变为无序状态时的形态变化，为心肌梗塞提供了潜在的指征。