Terahertz Imaging of Excised Breast Tumor Tissue on Paraffin Sections

This paper presents imaging and analysis of heterogeneous breast cancer tissue using pulsed terahertz (THz) imaging technology. The goal of this research is to validate and standardize a methodology for THz imaging capable of differentiating between heterogeneous regions of breast tumors. The specimens utilized here were obtained from breast tumors diagnosed as triple negative infiltrating ductal carcinoma (IDC). These tissues were fixed in formalin, embedded in paraffin, and cut into sections of three thicknesses: 10, 20, and 30 μm. All tissues were prepared on standard glass slides used in regular histopathology of hematoxylin and eosin (H&E) stained sections. The THz pulsed system is used to scan the two dimensional tissue sections with step size of 400, 200, and 50 μm. The experimentally measured THz fields reflected from single pixels identified in each region of the tumor are validated with the Fresnel reflection coefficient formulation. A variety of signal normalization and processing methods are investigated. The images are also validated with the standard histopathology images. The obtained results of three different tumors demonstrate strong capability of THz reflection imaging mode to distinguish between the heterogeneous regions in the tumor.