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AssigneeKoninklijke Philips Electronics N.V.
InventorRolf Karl Otto Behling
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The present invention refers to X-ray tubes of the rotary-anode type for generating a fan beam of X-rays. More particularly, the invention is concerned with a system and method for compensating a class of system-related disturbances of the focal spot position FS on a target area AT of the rotating anode RA and particularly for compensating the anode wobble in an X-ray tube XT of the aforementioned type, which occurs as a periodically wobbling inclination angle of the anode disk's rotational plane with respect to an ideal rotational plane (z=0) which is oriented normal to the rotational axis z of the rotary shaft S on which the anode disk RA is inclinedly mounted due to an inaccuracy during its production process. For this purpose, the electron beam generated by a thermoionic or other type of electron emitter of the tube's cathode C and thus the focal spot position FS on a target area AT of the anode disk's X-ray generating surface (anode target) are steered such that the focal spot FS stays within the plane PCXB of the central X-ray fan beam CXB.
A system for measuring and compensating a recurrent deviation (Δz) of the actual position from the desired position of an electron beam's focal spot (FS), said electron beam (EB) being emitted by an electron emitter of the X-ray tube's cathode (C) on a target area (AT) of an X-ray tube's rotary anode disk (RA), wherein said system comprises a position sensor (WS) for detecting the recurrent deviation during at least one period thereof, a beam deflection unit (BD) with an integrated controller for deflecting said electron beam (EB) based on the measurement results obtained from the position sensor (WS).
A method for measuring and compensating a recurrent deviation (Δz) of the actual position from the desired position of an electron beam's focal spot (FS), said electron beam (EB) being emitted by an electron emitter of the X-ray tube's cathode (C) on a target area (AT) of an X-ray tube's rotary anode disk (RA), wherein said method comprises the steps of detecting the recurrent deviation during at least one period thereof and deflecting said electron beam (EB) based on the measurement results obtained from the measurement step.
Dependencies are inferred from the claim text.