Terahertz imaging technology for localization of cancer tumours: a technical review

Currently, cancer is a large contributing factor in the increased mortality rates and at present the predictions are estimating an increased trend. The conventional medical cancer imaging modalities, for example X-Ray and Computed Tomography use ionizing radiation which is not tissue friendly for repeated assessments. The Terahertz (THz) cancer imaging offers novel opportunities for non-ionizing, non-invasive and early cancer detection, or diagnosis as well as improved cancer patient treatment follow-ups. In this review, a broad overview is given on the potential of THz radiation-based imaging and sensing as a technique for detection of various cancers cells. The THz radiation dynamics and interaction mechanisms with biological systems as well as parameter extraction and modelling for the observed THz image contrast are studied. The experimental studies on THz imaging and sensing are investigated with the goal approach to investigate the ex vivo, in vitro, and in vivo observations. The use of advanced analytic algorithms, specifically deep learning, is proposed for improved detection, discrimination of complex tissue with overlapping dielectric properties and development of clinical decision support systems. Research gaps in the THz imaging studies are identified based on recent trends, latest strategies suggested and the roadmap for future research direction provided.