Studying Oral Tissue via Real-Time High-Resolution Terahertz Spectroscopic Imaging

Terahertz (THz) waves are extremely sensitive to water content and biological composition (proteins, genes, and metabolites), which are the key regulator of cancer development. Hence, the application of THz spectroscopy and imaging is promising in the field of biomedicine, especially in cancer diagnosis. Currently, the diagnosis of cancer patients (including tumor borders, tumor stage, etc.) mainly rely on opti-cal microscope observation of pathological slices. The preparation of the slices is complicated and time consuming, and the microscopic field of view is small, which cannot effectively guide the precise removal of the tumor during the operation in time. To solve this problem, a label-free real-time high-resolution near-field THz spectroscopy imaging technique was developed. In this study, we successfully apply this technique to the oral tissue. Compared with conventional point-by-point scanning terahertz time-domain spectroscopy imaging, this technique can exhibit a real-time imaging rate (as high as 20 frames/s at 512 x 1024 pixels) and a field of view approximately 5 mm in diameter with a spatial resolution up to lambda/10 at 1 THz in near-field condition. The experimental results show that the terahertz spectroscopic imaging in this paper can clearly detect and identify not only biological tissues with different components, but also normal and cancerous tissues, as well as tissues with the same composition but different slice directions. This work lays an experimental foundation for the application of THz spectroscopy imaging to rapid label-free intraoperative diagnosis, and it provides a basis for promoting the wide application of THz technology in the biomedical field.