The invention relates to a medical system for introducing a catheter into a blood vessel of a patient, having a computer and control unit, a means for creating a transparent general view of the position of the vessel, a catheter with a reversible inflatable balloon located in the front area, to the outside of which a stent can be fitted for implanting into the vessel, a position locating system for the catheter with position and location sensors that can determine the position and location of the catheter, the system with at least one OCT (optical coherence tomography) sensor at a catheter end for the close-up area, with at least one IVUS (intravascular ultrasound) imaging sensor at a catheter end for the remote area and the computer and control unit having image processing and image display functions for the image sensors.
