In a computed tomography scanner (1) provided with an emitter (9) for emitting a beam of radiation (10) through an object to be analysed and a detector (11) for acquiring radiographies of the object, the detector (11) generates a synchronisation signal (SYNC) corresponding to its state of activation for acquiring the radiographies, and the emitter (9) is controlled via the synchronisation signal (SYNC) in such a way that the beam of radiation (10) will be emitted when the detector (11) is already activated.