Terahertz Imaging and Sensing for Healthcare: Current Status and Future Perspectives

Abstract

There is a keen interest in the exploration of new generation emitters and detectors due to advancements in innovation of new materials and device processing technologies which have opened up new frontiers in the Terahertz (THz) spectrum. Therefore, it is necessary to review the developments in THz technology for healthcare applications, their impact, implications and prospects for ongoing research and development. This paper provides a broad overview of the current status and prospects of application of THz imaging and sensing for the healthcare domain. We present current knowledge, identify existing challenges for wide scale clinical adoption of THz systems and prospective opinions to facilitate research and development towards optimized and miniaturized THz systems and biosensors that provide real operational convenience through emerging trends. Firstly, we provide an overview of the THz imaging and sensing techniques that exploit properties of THz generation and detection with emphasis on terahertz time domain spectroscopy (THz-TDS) and THz Metamaterials. The mechanisms of tissue image contrast and the application of THz imaging and sensing for biomedical applications in particular, the cancer detection application is reported. Secondly, an outlook toward the advancements in THz technology in the interface of healthcare 4.0 and its enabling technologies is explored for next generation smart and connected healthcare systems. Third, we identify the merits and existing challenges in THz cancer imaging and sensing and suggest prospective opinions to pave way to ongoing and future research. Further, we discuss the recent advances in THz imaging development and the contribution of near-field techniques based on plasmonic, and resonance based metasurfaces, waveguides etc. for breaking the diffraction limit towards development of THz systems that are convenient for point of care. We bring researchers a roadmap for future research scope.

Terahertz Radiation from High Electron Mobility Avalanche Transit Time Sources Prospective for Biomedical Spectroscopy

“…Technological advances in material sciences and microfabrication and device technologies in the last decade have facilitated the development of powerful sources, uncooled detectors and advanced imaging techniques, along with an extended scope for flexible electronics; biomedical, highfrequency sensing (particularly promising); and communication devices [42][43][44]. A few of the remarkable advancements in recent times leading the prospective application of THz in biomedical spectroscopy include [45,46]: THz wound and diabetic injury screening [47]; spectroscopy and imaging for cancer diagnosis [48][49][50]; a THz time-domain spectral (THz-TDS) system for biological macromolecule detection [51]; biomolecular and pathogen detection [52] and evaluation of transdermal drug delivery [53]; identification of tumor mutation in the central nervous system [54,55]; and intraoperative neurodiagnostics [56]. Further advancement in THz biophotonics, materials and instrumentation [57][58][59]; tissue imaging techniques [60][61][62]; and applied computing algorithms [63] may also open up newer frontiers in THz biomedical applications.…”

Roadmap on optical sensors

“…Because this frequency range has such exciting prospects, terahertz technology has clearly become an emerging field with significant growth on the scientific front. It is now entering the commercial markets for end-users in the healthcare and pharmaceutical industries [ 89 ], defence and security [ 90 ], non-destructive testing [ 90 , 91 ], telecommunications, and astronomy.…”

Selective Growth of Type‐II Weyl‐Semimetal and Van der Waals Stacking for Sensitive Terahertz Photodetection

“…The ORCID identification number(s) for the author(s) of this article can be found under https://doi.org/10.1002/adfm.202311008 DOI: 10.1002/adfm.202311008 between microwaves and infrared electromagnetic spectral region, exhibiting unique electromagnetic properties that it can transmit through many materials, THz spectroscopy and imaging can be used to identify concealed objects for security, biomedical imaging, remote sensing and many others. [1][2][3][4][5] These key priorities have prompted the progressive development of sensitive and performing systems exploiting coherent and powerful THz sources as well as fast, and portable photodetectors. [6,7] Even though there is a wealth of room-temperature detection technologies that have been proposed and commercially available based on thermal sensing such as Golay cells, [8] pyroelectric, [9] and bolometers, [10] they suffer from considerable drawbacks imposed by low sensitivity, low-speed, and the need of cryogenic operation.…”