Terahertz spectroscopic imaging of paraffin-embedded liver cancer samples

Paraffin-embedded liver cancer samples are measured with the terahertz time-domain spectroscopy (THz-TDS). It is found that the refractive index and extinction coefficient in the cancer tissue are different from those of the normal tissue. By raster scanning the samples we obtained the refractive index and extinction coefficient images of the sample. In the cancerous tissue, there are high gradient of the refractive index and extinction coefficient, while the refractive index and extinction coefficient in the normal tissue are almost constant. The THz image of the sample is compared to the optical microscopic image of the stained same sample, which reveals a structural complexity in the cancer tissue compared to the normal tissue.