Patent ID: 8265227

Claim:
An apparatus comprising: an x-ray tube comprising: an anode; a cathode configured to emit electrons toward the anode; and a plurality of electrodes configured to steer the electrons; a first generator coupled to the anode, to the cathode, and to the plurality of electrodes, the first generator configured to: generate a voltage differential between the cathode and the anode such that a current flows from the cathode to the anode; and supply a respective voltage to each of the plurality of electrodes to control at least one of a size and a position of a focal spot of the electrons on the anode; and a computer programmed to: determine a first starter voltage value for a first set of the plurality of electrodes, the first starter voltage value comprising a pre-determined voltage value for the first set of the plurality of electrodes and corresponding to one of a width, a length, and a position of a target focal spot determined using a second generator different from the first generator; cause the first generator to generate the voltage differential between the cathode and the anode; apply a first electrode voltage to the first set of the plurality of electrodes, the first electrode voltage based on the first starter voltage value; adjust the first electrode voltage and apply the adjusted first electrode voltage to the first set of the plurality of electrodes; and calculate a first final electrode voltage configured to generate the one of a width, a length, and a position of the target focal spot using the first final electrode voltage applied to the first set of the plurality of electrodes and using the first generator, the calculation based on the first electrode voltage and the adjusted first electrode voltage.