Distribution of IR radiation from a non-local source inside the biological tissue

Abstract

Non-invasive thermographic methods are based on the measurement of IR radiation from human tissue and, by which using Kirchhoff’s law, it restores the temperature of the examined body region. The disadvantage of this method is that the temperature image is noisy due to the thermal influence of the tissue layer between the organ under study inside the medium and the thermal imager. This degrades the quality of the image under consideration. Using the data on the temperature distribution inside the biological medium from a point source, the expression for the temperature from different-shape sources was obtained. The influence of various factors on the brightness increment distribution at the medium surface from a source shaped as a cylinder is studied. These include the source depth in the medium, the radiation wavelength, the absorption index, the heat transfer parameter, the cylinder height and diameter. The brightness increment from the source and the natural brightness of the skin surface are compared. It is shown how the source brightness changes the full brightness of the surface in a wide spectral interval.