A CBCT system is described that includes a radiation source for emitting a cone beam of radiation in a beam direction towards an object, a detector for detecting the cone beam of radiation, and a positioner for moving the radiation source and the object according to a scanning trajectory. The system is operated according to a sampling pattern that includes intersections of the scanning trajectory and a reconstruction trajectory, wherein motion of the radiation source is substantially confined to a spherical shell. The positioner moves the radiation source at a speed higher than a highest speed of the object by a factor of at least 10. The largest angular discrepancy between any vector in a range of the scanning trajectory and the nearest sample of the scanning trajectory does not exceed 10°, preferably 6° and more preferably 3°.