HEAT CAMERA

Typical Number in Hospital: 1

Cost Bands: 6

References:

There is a known relationship between the surface temperature of an object and its radiant power. This principle makes it possible to measure the temperature of a body without physical contact with it. Medical thermography is a technique whereby the temperature distribution on the surface of the body is mapped within a few tenths of a degree Kelvin. The human skin approximates to within 1% of a black body radiator and so a radiation thermometer can accurately detect the temperature of the skin. The detector in a radiation thermometer is typically arsenic trisulphide, indium antimonide, lead sulphide or thallium bromide iodine. The actual detector used will depend on the wavelengths (usually in the far infrared) required to be detected. Most thermography apparatus employs a mirror-type focusing device and the radiation beam is fed to the detector through a chopping disc which has a slot in it to interrupt the beam at a frequency of several hundred hertz so that an a.c. amplifier and phase sensitive detector can be used to amplify without the drift associated with d.c. amplifiers. See also thermography apparatus.

The best known use of the heat camera or thermograph is in breast scanning, where irregularities in the temperature distribution may indicate underlying disease.