Method for defining a location in a section under medical examination refers to a system of coordinates and subsequently to a collection of topological data

A targeting device (35) determines a first location in an area under examination with reference to a system (13) of coordinates and makes coordinates for the first location available as a first coordinate set allocated to the first location. A topology capture device (37) produces a record of topological data in a 3D expanded area around the first location. An Independent claim is also included for a device for displaying the extent of a section produced from a section under examination. A device for detecting direction of glance records a user's direction of glance at the section under examination. An input device (63) accepts the establishment of a data link through the user. A display device displays a dimension defined by the set of coordinates in the user's field of vision.