Optical coherence tomography is a non-invasive, optical imaging technique. It is based on low-coherence interferometry. Main applications can be found in medicine, due to its relatively high penetration depth in tissue (1-3mm) and an axial resolution in the m-range. OCT systems can be categorized into Time-Domain and Spectral-Domain systems. Especially the latter are becoming increasingly important. Goal of the presented thesis was the optimization of an existing Spectral-Domain-OCT system to enable in-vivo imaging of capillaries in the human nailfold. The novel aspect is that both, the amplitude and the phase information provided by the OCT system, is used to generate vascular maps of tissue. Corresponding evaluation software was developed in the programming language LabView. The system was characterized and tested on various skin regions. Specific focus of this work was set to the reproducibility of measurements of the vascular network in the nailfold.