Confocal fluorescence microscope for clinical dermatologic applications

Although skin is easily accessible to optical methodologies, biopsies are at present a widely used procedure in dermatologic diagnostics. However fluorescence confocal laser scanning microscopy (F-LSM) is a non-invasive imaging technique that allows depth resolved investigations of inflammatory and neoplastic skin disorders in vivo and at high resolution. By applying substances onto or into the epidermis F-LSM is well suited to obtain information regarding the morphological structures of the skin down to a hundred micrometers below the skin surface. Compared to conventional light microscopy of histological sections this optical method has a clear advantage in the case of kinetic measurements. To this end, we have designed a portable confocal fluorescent microscope for future dermatologic studies, offering a field of view of 600?m x 600?m. Based on a dual-axis MEMS mirror (Fraunhofer IPMS, Germany) the confocal character of the system resides in the use of the same path for illumination and detection with spatial filtering of the signal collected from the subsurface analysis plane. Illumination is provided by a 488nm laser and the backscattered fluorescence light is separated from the illumination light by a filter, before being detected behind the pinhole. To reconstruct the image the measured intensity and position information is correlated. The ability to perform crosssectional imaging in the skin will be given by an integrated z-shifter.