• actinic keratosis;
  • photodynamic therapy;
  • red traffic lights


LED light sources for photodynamic therapy have become increasingly popular due to their narrow emission spectra that accurately match the absorption spectrum of porphyrins. Photodynamic therapy at low fluence rates has been shown to be as effective as high output irradiation for treatment of non-melanoma skin cancers. Fifteen patients with multiple non-hypertrophic actinic keratoses covering the scalp and the face were treated with aminolaevulinic acid photodynamic therapy using ordinary red LED traffic lamps as light source. All 15 patients improved clinically after one photodynamic therapy session. Only two patients required a second session to obtain satisfactory remission. Pain was minimal during these sessions. Red LED traffic lights constitute a simple alternative to far more complicated and expensive PDT light sources.