A medical imaging installation and a method for a medical imaging installation are disclosed for defining a specific position on the surface of an object. In at least one embodiment, the installation has a support apparatus for an object, a device for recording measured data from the object in order to produce an image of the object, a unit for displaying an image obtained from the object, and a device, arranged on the installation in a defined fashion, for projecting a light pattern onto the surface of the object. The light pattern is inserted appropriately into the displayed image of the object in order to define a specific position on the surface of the object.