Thermal Imaging for Biological and Medical Diagnostics
The change in local temperature of blood, tissue, and skin in biological systems is determined by the difference in the thermal energies received and lost by conduction transfer and advection, as well as by the thermal energy released by chemical reaction processes such as metabolism. The use of temperature (measured at a convenient location such as the ear, armpit, or mouth), as an indicator of health has been in routine use for a very long time. However, even in such use, it is widely recognized that different healthy individuals can have different temperatures. In fact, the same healthy individual can have different temperatures at different times, based on the local environmental conditions, blood perfusion rates as controlled by the nervous system, and metabolic rates as controlled by a variety of complex factors.