Catheter device for insertion into an area being examined, in particular into a vessel or cavity-containing organ in the body of a person or animal, wherein in the area of the catheter tip a device (3) is provided for emitting excitation light for light-optically exciting an area being examined surrounding the catheter tip, furthermore a device (3) is provided for collecting response light emitted, owing to excitation, from the area being examined, and furthermore a position sensor (13, 24, 27) is provided enabling the catheter tip's spatial position and/or orientation to be registered in a system of coordinates of a position-registering system (7, 14).