1. Operating system for carrying out surgical interventions on a patient ( 1 ), comprising a storage device ( 4 ) for storing image data of an organ of a patient ( 1 ) that is invisible from outside, a surgical instrument ( 2 ) for carrying out the surgical intervention a position sensor ( 6 ), fitted on the surgical instrument ( 2 ), for detecting the spatial position of the surgical instrument ( 2 ), and a processing device ( 5 ) for calculating the spatial relationship between the position of the surgical instrument ( 2 ) and the organ, which is represented by the image data, and for inserting the region of the image data that correspond to the surroundings of the surgical instrument ( 2 ) at the correct position into a display device ( 8 ).