Filing Date: 2003-10-01.-- Priority Data: ES (2002-10-01) (P200-20-22)The invention relates to a device which is used intra-operatively to localise carcinogenic tumours and ganglia precisely and in a three-dimensional manner and to correlate the surgical instruments with the images in real time. The structural elements of the functional navigator include: a surgical navigator, a camera which is used to obtain functional images, the position-finding elements of the camera and the surgical instruments and the specific software program which combines all of the information from the aforementioned elements. The surgical navigator is essentially characterised in that the position of the cameras which acquire the functional images is controlled by the navigator by means of emitters or reflectors which are disposed in said cameras. The information relating to the camera images and the position of same, which is determined by the navigator, is analysed by a specific software program and combined with the position of the surgeon's surgical instruments in order to obtain images.