Method Development of Multi-Layered Optical Skin Phantoms

Abstract

The increasing research interest in and use of optical medical technologies has led to a growing need for synthetic testing materials with tissue-mimicking optical properties, known as optical phantoms. Many different materials and methods have been used to create such phantoms but the field currently lacks standardization and repeated results. Optical phantoms made for dark skin tones and for short wavelengths of light are also missing from research. This project tests and builds on previously established methods for creating optical phantoms made out of PDMS silicone. A method for creating a multi-layered skin phantom in which each layer mimics the thickness and absorption of one of the main layers of human skin is developed and presented. Four versions of this phantom are made: two of them mimic the absorption of fair skin and two of them the absorption of dark skin. For each skin colour, one of the phantoms mimic the absorption at a wavelength of 405 nm and the other the absorption at 630 nm. A correlation between the concentration of nigrosin (an absorbing agent) and the absorption coefficient of the resulting phantoms is determined using spectrometry. This correlation can work as a guide for how to reach a desired absorption coefficient.