Fluorescence Excitation Photography of Epidermal Cellular Proliferation

Summary Background Fluorescence excitation provides the ability to interrogate innate molecules whose radiation emission correlates with specific functional states of tissue. Objectives The present study demonstrates the effectiveness of a novel ultraviolet (UV) fluorescence excitation photography system in its ability to image rapidly proliferating epidermal skin lesions by capturing endogenous fluorescence emissions attributed to tryptophan. Methods A clinical prototype UV fluorescence excitation photography system was used to acquire images of endogenous fluorescence ascribed to tryptophan. Results Twelve human subjects and 11 ex vivo samples with various skin lesions consistently exhibited increased endogenous fluorescence at 340-nm wavelength upon excitation at 295 nm in rapid epidermal proliferations, including psoriasis, actinic keratoses and basal cell carcinoma, compared with surrounding normal skin. In contrast, nonproliferating lesions showed decreased fluorescence. Conclusions This simple but robust point-and-shoot imaging system may offer a clinically useful, noncontact, noninvasive device for the diagnosis and detection of skin disease. As opposed to structural imaging modalities, fluorescence excitation imaging at 295/340-nm wavelengths offers high-sensitivity, wide-field functional imaging of cellular proliferation without the need for externally applied dyes or lengthy image processing. Furthermore, the image is instantly available and does not require interpretation or reconstruction.