Toward Clinical Cancer Imaging Using Terahertz Spectroscopy

Cancer imaging using terahertz (THz) electromagnetic waves has the potential to overcome the drawbacks of existing cancer imaging techniques because of the unique properties of THz radiation. It is nonionizing, highly sensitive to water molecules, and suitable for the observation of many biomolecular characteristics based on low-energy vibrational modes. Consequently, it is advantageous to use THz cancer imaging for detection, especially of superficial carcinomas in soft tissues. However, there are three primary challenges facing this type of cancer imaging that must be addressed before it can be applied medically: the limited penetration depth in hydrated tissues, the difficulty of obtaining molecular resonance fingerprints of cancers, and the low image contrast between tissues. These challenges can be overcome by applying several state-of-the-art techniques; the penetration depth has been enhanced sufficiently to observe cancer lesions deep inside tissues by using freezing and penetration-enhancing agents: the biochemical modification of DNA can be utilized to track the resonance fingerprints of carcinogenesis at the genomic DNA level; and nanoparticles can increase the THz imaging contrast if they are employed similarly to how they are used in magnetic resonance imaging. These solutions are important to enable THz cancer imaging to be performed in clinical settings.