The Herschel Heritage to Medical Thermography

The discovery of infrared radiation by William Herschel in 1800 led to John Herschel’s study of solar radiation that he imaged by evaporography. This he termed a thermogram. The measurement of temperature in medicine advanced with Dr Carl Wunderlich, who showed the significance of the use of temperature measurements for diagnosis of fever and for monitoring the course of temperature in relation to disease. It was William and John Herschel’s discovery of infrared radiation that has ultimately opened up many applications for thermal imaging. Radiometric determination of human body (skin) temperature is now achievable. Remote sensing of infrared radiation first developed in the 1940s and has continued to develop steadily since 1960. Modern high speed and high resolution camera systems have now reached a dramatic level of performance at more modest costs, which medicine can now employ for non-invasive and quantifiable imaging. This has applications in many areas of medicine both for diagnostics and monitoring treatment. In recent years the acute threat of pandemic infection has increased, heightened by today’s ever expanding world travel. Special interest has been shown in the potential of thermal imaging for airport and travel screening. This is in effect where Dr Wunderlich’s studies began, and it has yet to be proven that the technique can be responsibly employed for efficient screening of large numbers of the travelling public.