THz imaging of nucleobases and cancerous tissue using a GaP THz-wave generator

We constructed a terahertz (THz) spectroscopic imaging system using a GaP THz-wave generator with automatic scanning control, and demonstrated power-transmission imaging measurements. To characterize the system, images of polyethylene pellets containing cytosine powder at various concentrations were taken. At a resonance frequency of 2.86 THz, the imaging system detected 5000 ppm cytosine. In addition, we demonstrated that THz imaging has a possibility to distinguish regions of metastatic cancer from normal tissue in liver, by comparing a THz-wave image at 0.835 THz with that at 1.465 THz.