Characterization of probe contact effects on diffuse reflectance spectroscopy measurements

Diffuse reflectance spectroscopy (DRS) is a rapid, non-invasive optical method widely adopted to gain diagnostic information of tissue. The most flexible approach to this method is a fiber-optic contact-probe used with a spectroscopy system. A challenge of this method is that the external pressure brought by the probe can significantly affect the tissue optical properties as well as the light coupling into the probe, and thus influence the collected DRS-spectrum. In this study we investigate and characterize the effect of probe pressure on DRS-spectra obtained with a calibrated loaded-spring system used with a fiber optic probe in the range (400 - 1600) nm. A multilayer FE-model of the indentation is developed to get a better insight of the distribution of pressure and stresses inside the skin under indentation.