Encyclopedia / T / Thermography

Thermography

Definition

Thermography is a technique for sensing and recording on film hot and cold areas of the body by means of an infrared detector that reacts to blood flow.

Disease states that manifest increased or decreased blood flow present thermographic patterns that may possibly be distinguished from normal areas.

Description

Thermography measures the slightest variations in temperature of soft tissue in the body using infrared heat sensors. Thermography for use in cancer screening is a recent invention based on the concept that cancer gives off more heat than normal tissue. It was originally a much-heralded technique, since it does not involve radiation, or putting anything else in the body.

Unfortunately, this technique has not proved accurate, there are too many false positives and false negatives. Not all cancers give off heat, and of those that do, some are too deep, or located under wedges of fat, and the heat does not register on the device.

Though thermography does not detect cancer, some European physicians believe that it can define the aggressiveness of a cancer known to exist. The more aggressive a cancer is, the more heat it gives off. This has not been substantiated and thermograms have not been used for this purpose in the U.S.

Questions

When is thermography helpful?

How accurate can it be?

There may be uses for thermography in other fields, including dentistry and the diagnosis of headaches.

In dentistry, facial skin temperature can be measured in a clinical setting, without direct skin contact, by monitoring the emitted infrared radiation. This is the basis of static area telethermography (SAT) and dynamic area telethermography (DAT). SAT has recently been shown to be of help to the dentist in (1) the diagnosis of chronic orofacial pain, (2) as a unique tool in assessment of TMJ (temporomandibular joint) disorders, (3) as an aid in assessment of inferior alveolar nerve deficit, and (4) as a promising research tool.