In this work we will demonstrate that the stratified medium theory model [1,2] can be used to model the THz reflection [3] of both dry skin conditions, and complicated areas of skin such as the palm (which has a thick layer on the outside) [4]. This modelling can be used together with other techniques, such as spectrogram analysis, to show the location of boundaries in the skin: allowing diseased regions inside the skin to be recognized. 

Using data from a clinical study of in vivo THz imaging conducted with the University Hospital of Coventry and Warwickshire, we apply these methods to measurements of both healthy skin and diseased skin from a variety of areas of the body. We show their dynamic hydration profiles and break down some of the distinctions between healthy and dry skin.

 [1] Bennett D, et al. “Stratified media model for THz reflectometry of the skin”. IEEE Sensors Journal. (5), 11 (2011).                                              [2] X Ding, et al. “Retrieving the dynamic hydration profile of skin in vivo with a handheld THz probe”. IRMMW-THz 2023.                                      [3] H Lindley-Hatcher, et al. “A robust protocol for in vivo THz skin measurements”. J. Infrared Millim. Terahertz Waves, (9), 40 (2019).                    [4] M Egawa. “Raman microscopy for skin evaluation”. Analyst RSC. (146), 1142  (2021).