All things, including the human body emits infrared
Thermography has been used in the field of medicine for the last 30 years and its safety and effectiveness have been proved beyond doubt with volumes of peer-reviewed studies and medical literature as proof. Infrared video cameras have proved to be a sensitive diagnostic tool for a myriad variety of clinical and experimental situations. Breast cancer, nervous system disorders, neck and back problems, pain syndromes, arthritis and soft tissue injuries are some cases wherein thermal imaging has proved to be useful. This is a completely non-invasive technique and does not require the use of radiation or other potentially harmful elements.
Intensive thermographic studies have proved an anticipated baseline of normal pattern of thermal imaging of a human body, both in steady state as well as dynamic situations. Testing using a thermal imaging camera or infrared video camera, the deviations from characteristic normal temperature patterns are noted. These deviations are associated with different pathological phenomena that provide the basis for non-invasive investigations.
Today, thermal imaging cameras are the best way to study skin temperature for clinical diagnosis. For instance a 'hot spot' indicates inflammation of the skin, directly overlying injury whereas a 'cold spot' is a reduction in blood supply usually due to thrombosis or scar tissue. Tendons and joints show inflammatory changes as much as two weeks before the symptoms are visibly apparent. Thermal imaging also can be used to assess the vasculature and blood flow to tissues before and after exercise. Epileptic foci and tumors can be detected by observing the patterns and 'thermal signatures' in an infrared video camera.
High resolution dynamic thermal imaging cameras provide intra-operative real-time physiological, anatomical, and pathological information and hence are useful during surgical procedures. Dynamic infrared imaging has been applied in a variety of neurosurgical, cardiovascular and melanoma cases.
Last but not the least; thermal imaging is also useful in veterinary practice. To a trained practitioner 'thermal signatures' of the animals taken from an infrared video camera relay information about blood flow deviations, indicating the presence or absence of health issues.