Calculation of skin temperature increase caused by subcutaneous veins perpendicular to the skin surface.

A graphical solution of the temperature increase at the surface of a homogeneous solid due to a linear heat source perpendicular to the surface is given. The calculations correspond to clinical situations for studies of the skin temperature increase over vessels approaching the surface from deeper layers of tissue. Estimations have been made of the maximum distance from the skin surface at which a vein of given diameter may be positioned to be detected in a thermogram. The necessary heat source power to produce a detectable increase in skin temperature is presented graphically as a function of heat source depth. The results can be used for the analysis of the skin temperature pattern by infrared thermography.