Medical examination and/or treatment system having a catheter (1) with a sensor (3, 4) connected to an image recording system, said sensor being connected to an image processing unit (24, 25) for evaluating the sensor signals recorded in an examination area, a display unit (26) for displaying the images (12) of the image processing unit (24, 25) and a means for detecting the position and/or orientation of the catheter tip, whereby the system can generate three-dimensional images from the two-dimensional images (12) of the image recording system based on the detected position and/or direction of the catheter tip.