10 neurosurgical instruments and apparatus, namely, neurosurgical arcs, biopsy kits, phantom bases, headrings for neurosurgery, x-ray registration kits, evacuators, microscope adaptors, ultrasound adaptors, reference clamps, steri-boxes, registration markers and marker spheres, reference rings, pointers, instrument adaptors, virtual keyboards, dental referencing devices, instrument calibration matrixes and fixation rings; radio-therapeutic apparatus, namely, radio-therapeutic and radiosurgical mask systems, headrings, verification helmets, localizers, torque wrench sets, fixation pins, head and neck immobilization devices, body markers, couchmount kits, target positioners, adaptors, evacuators, laser pointers, verification phantoms, collimators, film holders, phantom pointers, patient tray and accessories, vacuum cushions, couch stabilizers, tracking devices for exact patient positioning; devices for detection and adjustment of radiation points for medical purposes; intra-operative, image-guided localization units for surgical, in particular for neurosurgical, stereotactic and radio-surgical applications