Thursday, November 29, 2018

Abstract-THz in vivo measurements: the effects of pressure on skin reflectivity



Jiarui Wang, Rayko I. Stantchev, Qiushuo Sun, Tor-Wo Chiu, Anil T. Ahuja, and Emma Pickwell MacPherson

Fig. 1 Experimental setup and stratified media model illustration. (a) The THz beam is focused onto the top interface of the quartz window, and the reflected signal is collected and then detected by a photoconductive antenna. (b) Schematic illustration of the layers within human skin: each layer has a different permittivity. The hydration profile of skin is approximately linear in the SC and epidermis, and constant in the dermis.


https://www.osapublishing.org/boe/abstract.cfm?uri=boe-9-12-6467


Terahertz (THz) light is non-ionizing and highly sensitive to subtle changes in water concentration which can be indicative of disease. The short THz penetration depth in bio-samples restricts in vivo measurements to be in a reflection geometry and the sample is often placed onto an imaging window. Upon contacting the imaging window, occlusion and compression of the skin affect the THz response. If not appropriately controlled, this could cause misleading results. In this work, we investigate and quantify how the applied pressure affects the THz response of skin and employ a stratified model to help understand the mechanisms at play. This work will enable future THz studies to have a more rigorous experimental protocol, which in turn will facilitate research in various potential biomedical applications under investigation.
© 2018 Optical Society of America under the terms of the OSA Open Access Publishing Agreement

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