An optical coherence tomography system includes a catheter in which is arranged a plurality of light conducting fibers. It further includes a plurality of optical units. Light from the proximal end to the distal end and signals from the distal end to the proximal end can be transmitted simultaneously in different fibers. Time is saved through the simultaneous signal processing of signals from different fibers. That is advantageous particularly in the imaging, by means of coherence tomography, of blood vessels that have to be occluded for said imaging.