17 Jun 2002
A new portable system for identifying skin cancer uses fluorescence imaging.
A multidisciplinary collaboration of Scottish researchers has developed a compact, low-cost imaging system for detecting skin cancer by making it fluoresce, writes Jacqueline Hewett. Earlier systems based on laser-induced fluorescence tend to be large, but the new system, described in Photochemistry and Photobiology 73, 278-282 (2001), uses only a phosphor-coated bulb to induce fluorescence. This has allowed the researchers, based at the University of St Andrews in the UK, to develop a portable instrument that can be easily integrated into existing clinical practice.
The scientists induce fluorescence in the skin by administering a commercially available, light-sensitive drug topically to the suspicious region. This light-sensitive drug, or photosensitizer, preferentially accumulates in cancerous tissue and fluoresces when exposed to violet light at 400 nm, presenting a characteristic fluorescence signature at 630 nm within any cancerous areas. The new imaging system identifies areas displaying this specific signature, allowing dermatologists to determine accurately the extent of the skin cancer.
The technique can be combined with photodynamic therapy (PDT). PDT is a newly emerging technique for killing cancerous cells using laser light of the appropriate wavelength. When the laser light interacts with the photosensitizer, the amount of fluorescence decreases. The imaging system is capable of monitoring this reduction throughout treatment and the scientists hope that this will help to optimize treatment given during outpatient clinics.