Highly Sensitive Terahertz Imaging Method for Paraffin Embedded Cancer Samples

Differentiating thin film cancer tissue from normal tissue with terahertz (THz) light has been investigated for decades, primarily with breast cancer samples. However research is seldom done on thin film oral cancer tissue, and this typically has low contrast compared with normal tissue in ordinary THz geometries. In this paper, we demonstrate how a window-sample-water sandwich structure can significantly enhance the contrast in reflection geometry terahertz time domain spectroscopy. Our method is highly sensitive compared to traditional THz transmission or reflection imaging. We image paraffin-embedded oral cancer tissues to show how the proposed method increases the sensitivity for solid low-absorptive thin film cancer samples by over a factor of 5.