Application of thermal imaging in forensic medicine

Abstract

A thermogram or thermal image provides a two-dimensional map of skin temperature distribution. The technique, which uses the IR radiation of objects as the source for imaging, has significantly developed since it was launched for medical imaging in the 1960s. Modern focal array equipment provides both high spatial and high temperature resolution. Body temperature measurement is a traditional approach to estimating the time of death. A number of protocols have been described for that purpose. Another application for IR imaging is the assessment of environmental conditions of detected corpses (water, cars, weather conditions). Skin burns can be easily visualized by thermal images. Thermal imaging was also used to investigate the skin temperature at the entry point after shots were fired from 0.22–0.38-calibre handguns. Whiplash injuries gained importance in liability cases after car crashes. Occasionally thermal images can provide additional information in this pathology, but this might not be always unambiguous. Thermal imaging was successfully used as an alternative to Polygraph testing. In this application, psychological effects on blood flow are investigated, and an accuracy of 78% in detecting deceptive subjects is reported. Thermal imaging can be used as a method of temperature measurement in a number of applications of forensic medicine. When used for medico-legal evidence, it is important that a standard protocol for subject preparation, image capture and analysis is used. A scheme for standardization of the latter is proposed.