Terahertz spectroscopy of human skin tissue models with different melanin content.

Xomalin G Peralta,Ibtissam Echchgadda,Dawn Lipscomb,Gerald J Wilmink

doi:10.1364/boe.10.002942

Abstract

Terahertz imaging has been proposed for burns and skin cancer identification. However, the role of melanocytes, melanosomes, melanin content and distribution in determining the terahertz optical properties of human skin has not been investigated. We use terahertz time domain spectroscopy to measure the optical properties of in vitro pigmented human skin tissue models from Asian, Black, and Caucasian donors. Spectra were collected at various time intervals and used to extract the absorption coefficient and index of refraction at terahertz frequencies. Our results indicate that the degree of cell differentiation and type of donor both contribute to the measured terahertz optical properties.

Highlights

The terahertz (THz) region of the electromagnetic spectrum is located between the infrared and microwave regions, spanning frequencies from 0.1 to 10 THz
We compared the normalized percentage difference in the absorption coefficient and in the index of refraction observed between the three skin donor tissue models in Day 16 (>16% for the absorption coefficient and >9% for the index of refraction) to those previously observed between human basal cell carcinoma and healthy tissues (
The absorption coefficient and index of refraction obtained for all skin tissue models fall within the acceptable range for pure collagen and water, and are comparable to those obtained in other studies on human skin

Summary

Introduction

The terahertz (THz) region of the electromagnetic spectrum is located between the infrared and microwave regions, spanning frequencies from 0.1 to 10 THz (wavelengths from 3000 to 30 μm). In order to facilitate the development of these applications, it is important to understand the fundamental mechanisms governing terahertz-skin interactions [7,9,18]. To this end, several studies have been conducted to characterize the optical properties of human skin tissues at THz frequencies ex vivo [18,19,20,21] and in vivo [10,22,23,24,25]. The dielectric permittivity function is given by

Methods

Discussion

Conclusion