A study carried out in Auckland among the caucasian, or pakeha, population reached the conclusion that they had the highest incidence of melanoma in the world. Melanoma is a dangerous cancer. It occurs as a tumour of melanocytes, the pigment forming cells of the skin. It can be treated very successfully, if it is detected in the early stages. So it is important to have good techniques to detect melanoma early, especially in New Zealand.

Moles are spots on the skin. A low number of babies are born with a mole but most people gain moles over their lifetime. The shade of a mole is caused by the pigment cells (melanocytes). Most moles are not dangerous, but nearly 50 percent of melanomas start in moles. This is why doctors want to check out moles.

SIAscopyTM (spectrophotometric intracutaneous analysis) uses the way light interacts with skin components and how it is reflected and absorbed to detect if the melanocytes have migrated deeper into the skin than normal, which indicates cancer. The distances into the skin are quite small. SIAscopyTM can "see" 2 mm into the skin – this is enough to detect if the melanocytes are deeper than they should be.

To look for melanoma, visible light and infrared light are used. Melaninhaemoglobin and collagen absorb and reflect light differently, and this method can show the quantities of these skin components that are present. It has been found that melanoma has a particular pattern of these components.

The information gained from shining light from various parts of the spectrum at a mole on the skin is fed into a computer. Like other imaging techniques, sophisticated software produces images that are useful to show a doctor if melanoma is present or not.

This non-invasive technique for detection of melanoma using light is based on research done by a scientist, Dr Symon Cotton, in the United Kingdom when he was studying for his PhD.

    Published 23 July 2007