10 Neurosurgical instruments and apparatus, namely, image-guided localization systems for surgical purposes; radiotherapeutic apparatus; medical systems and components for positioning patients precisely for radiotherapeutic or neurosurgical applications as parts of medical devices, namely, image-guided localization systems for radiotherapeutical purposes; computerized tomography apparatus and nuclear spin tomographs for medical use, medical devices, namely, intra-operative, image-guided localization systems for surgical applications, in particular for neurosurgical, orthopaedic, stereotactic and radiosurgical applications and for applications in ear, nose and throat (ENT) surgery; medical instruments and apparatus for software-controlled precision treatment in neurosurgery, orthopaedics, radiotherapy and in ear, nose and throat (ENT) surgery, namely, medical referencing markings and referencing marker arrays attached to medical and surgical instruments and attached to patients for referencing and/or registering purposes, in particular referencing markings and referencing marker arrays which can be attached directly or via clamps to surgical instruments or apparatus using detachable adaptors; medical and surgical pointers for software-controlled precision treatment in neurosurgery, orthopaedics, radiotherapy and in ear, nose and throat (ENT) surgery, namely, pointers for registering purposes comprising tactile and contact-signaling tips; medical devices for software-controlled precision treatment in neurosurgery, orthopaedics, radiotherapy and in ear, nose and throat (ENT) surgery, namely, calibration phantoms, head holders, x-ray registration kits, localizers, instrument calibration apparatus, planning stations, couch mounts, collimators, target positioners, radiation devices, instruments and apparatus for three-dimensional registration and referencing of patients