A computer tomography system has a stationary x-ray tube, that has an
anode ring and at least one cathode ring, that extends through
360.degree. in a system plane perpendicular to a system axis, and a
vacuum region that is at least partially delimited by a light-permeable
and/or infrared-permeable vacuum window is provided between the anode
ring and the at least one cathode ring. A support frame is rotatable
around the system axis parallel to the system plane, on which are
arranged, in at least one angle position, a system with at least one
laser for local activation of electron emission at the at least one
cathode ring, and a filter and/or collimator set, and a radiation
detector opposite the filter and collimator set.