In an image display device configured to be connected to a network, a method of communicating over the network with a remote device on the network is disclosed. The method includes providing a static air temperature to a data processing device. With regard to a reduction of artifacts, a projection image based correction is based upon projection images of a mask data set which show the neurosurgical apparatus without the head of the patient or the head of the patient without the neurosurgical apparatus. The worm drive mechanism includes a screw that engages the set of slots for radial contraction of the band.