http://repub.eur.nl/res/aut/10734/ List of Publications en http://repub.eur.nl/static-eur/img/logo.png http://repub.eur.nl http://repub.eur.nl/res/pub/1069/ 2003-11-13T00:00:00Z Photodetection and photodynamic therapy (PDT) of malignant and premalignant skin lesions are based on the activation of a photosensitive drug (photosensitiser) with (laser) light. The ideal photosensitiser accumulates selectively in the (pre)malignant tissue. Upon illumination with light of an appropriate wavelength, the photosensitiser fluoresces and reacts with cellular substances and/or produces singlet oxygen. This is causing cell death and thus destruction of the (pre)- malignant tissue. The fluorescent properties can also be used for diagnosis of (pre)malignant tissue, which is not visible for the eye. The photodynamic properties can induce undesired side effects like prolonged skin photosensitivity and erythema. The starting point of this thesis was to evaluate the use of other agents than porphyrin derivatives or protoporphyrin IX (PpIX) for photodetection purposes in order to avoid undesired side effects which are related to the use of photodynamically active drugs.