To allow safe treatment of a patient, in particular a puncture or biopsy using a needle, a 2D sectional image of an implant plane and a further 2D sectional image of an orthogonal plane are generated from a 3D image data record of a region to be examined. The two planes are hereby oriented such that the needle is on the one hand located within the implant plane and on the other hand is oriented in a perpendicular manner in respect of the orthogonal plane. The parallel display of the 2D images allows the doctor to acquire the relative position of the needle in relation to the region to be examined in a simple and intuitive manner.