Variation of Fluorescence with Temperature in Human Tissue

Abstract

Previous studies have reported that fluorescence in human tissue is a temperature dependent phenomenon. The most apparent effect is the inverse relationship between fluorescence intensity and temperature. Here, we present the effects of temperature on fluorescence in human tissue using skin and adipose tissue in vitro and skin in vivo. Fluorescence and diffuse reflectance measurements were made while the temperature of the specimens was increased, and an inverse Monte Carlo algorithm was used to calculate optical properties as a function of temperature. In vitro and in vivo experiments showed a decrease in fluorescence intensity due to temperature increase. The fluorescence intensity showed no relationship to the optical properties in the physiological temperature range, suggesting that changes in optical properties are not the primary mechanism by which fluorescence is affected by temperature. This study confirms that fluorescence decreases with increasing temperature in human tissue in vitro and in vivo. Our results further suggest the presence of a temperature dependent non-radiative decay mechanism.