Scanning for skin cancer

Cancer cells divide more rapidly than normal cells, thus generating more energy as heat. However, the temperature difference between healthy and cancerous skin cells is extremely small. This is why it is very difficult to detect the melanoma when it is in stage 2 (still only on the skin) before it progresses to stage 3. At this stage, the melanoma hits the lymph nodes or even the bloodstream and thus it becomes more difficult to treat. To help the diagnosis of cancerous melanoma early on, researchers at John’s Hopkins have designed a noninvasive infrared scanning system that helps physicians determine whether pigmented skin growths are benign moles or actual cancer. The device works by looking at the tiny temperature difference between healthy tissue and a growing tumor.
To make the difference in temperature between the healthy skin and the melanoma stand out, some steps have to be taken before the device can detect it. First, they cool a patient’s skin with a one-minute burst of compressed air. When the cooling is stopped, they immediately record infrared images of the target skin area for two to three minutes. They do this because cancer cells typically reheat a lot quicker than the healthy cells. This difference in reheating can be captured by the infrared camera and viwed through sophisticated image processing.
Currently, theirs is a pilot study being conducted where lesions that have been dermatologist identified undergo the procedure and then a biopsy is taken to prove whether or not the result obtained by the infrared device was correct. This technology could also be incorporated into full-body scans in the future for patients with a large number of pigmented lesions.

Geraldine Pena-Galea
http://gazette.jhu.edu/2010/03/01/scanning-for-skin-cancer-infrared-system-looks-for-melanoma/