Multispectral fluorescence detection of pigmented cutaneous tumours

Abstract

We investigated pigmented skin tumour lesions in vivo and ex vivo, including benign and dysplastic nevi, as well as malignant lesions, such as pigmented basal cell carcinoma (BCC) and malignant melanoma (MM) lesions, to obtain a complex view about the feasibility of different excitation sources solely and/or in combination to induce fluorescence signal useful for diagnosis of various low-fluorescent cutaneous neoplasia. A specialized multispectral analysis of the data obtained was applied by using excitation in broad spectral range, covering ultraviolet, visible and near-infrared spectral range, that contribute considerably to: (1) fundamental determination of tumour tissues’ spectral properties, and (2) to increase the accuracy in determining the type of cutaneous pathology. The chromophores, related to the formation of ultraviolet and visible (UV-VIS) fluorescence in human normal skin and its pigmented lesions are mainly amino acids – tryptophan, tyrosine; structural proteins and their cross-links – collagen, elastin, keratin; co-enzymes - NADH, flavins; vitamins and lipids. In the near-infrared (NIR) spectral region, skin fluorescence emission properties are related to the presence of melanin pigment, lipids and endogenous porphyrins, if any, as the highest impact on the resultant emission spectrum is due to the melanin compound.