Visualization and analysis of microstructure of materials or tissue play a pivotal role in industrial manufacturing and pathological diagnosis. Microwave-induced thermoacoustic microscopy (TAM) enables imaging at the microscopic level. TAM, however, is currently qualitative and cannot quantitatively measure intrinsic electromagnetic parameters of materials/tissue, such as conductivity. Here, we propose a quantitative microwave-induced thermoacoustic microscopy (qTAM) approach capable of quantitatively recovering conductivity using a finite element-based iterative inversion strategy coupled with thermoacoustic measurements. We validate the qTAM approach using tissue-mimicking phantoms, and demonstrate its applications to imaging flexible circuits, ex vivo rabbit bone, and rat brain tissues. The results obtained suggest that qTAM may have the potential to become a quantitative tool for microscopic imaging of materials and tissues.

中文翻译：

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定量微波诱导热声显微镜

材料或组织微观结构的可视化和分析在工业制造和病理诊断中发挥着关键作用。微波诱导热声显微镜 (TAM) 能够在微观水平上进行成像。然而，TAM 目前是定性的，无法定量测量材料/组织的固有电磁参数，例如电导率。在这里，我们提出了一种定量微波诱导热声显微镜（qTAM）方法，能够使用基于有限元的迭代反演策略与热声测量相结合来定量恢复电导率。我们使用模拟组织模型验证了 qTAM 方法，并展示了其在柔性电路、离体兔骨和大鼠脑组织成像中的应用。获得的结果表明 qTAM 可能有潜力成为材料和组织显微成像的定量工具。