X-ray CT apparatus having focal spot position detection means for the X-ray tube and focal spot position adjusting means

An X-ray computerized tomographic (CT) apparatus having an X-ray detector, the apparatus comprising:

• an X-ray tube which is freely movable in at least one of a horizontal direction and a vertical direction;
• detection means, disposed in the vicinity of the X-ray detector, for detecting a dislocated degree of the focal spot position of the X-ray tube;
• and
• means for automatically controlling the focal spot position of the X-ray tube based on data obtained from the detection means so that the focal spot position of the X-ray tube remains fixed in a predetermined position;
• wherein the focal spot position controlling means includes deflection means for deflecting an electron beam emanated from an electron generating means by an electric field or a magnetic field, so that the focal spot position of the X-ray tube remains fixed in a predetermined position even when the focal spot position is deviated.

An X-ray computerized tomographic (CT) apparatus for use with a continuous scanning operation, having an X-ray detector, the apparatus comprising:

• an X-ray tube which is freely movable in at least one of a horizontal direction and a vertical direction;
• detection means for detecting dislocated degrees of the focal spot position of the X-ray tube at a plurality of rotation positions during a single scanning rotation of a gantry;
• and
• averaging means by which the an average value calculated from the plural dislocated degrees detected by the detection means;
• and
• means for automatically controlling the focal spot position of the X-ray tube in a next scanning rotation of the gantry, based on data, including the average value for a preceding rotation, obtained from the averaging means.

An X-ray computerized tomographic (CT) apparatus for use with a continuous scanning operation, having an X-ray detector, the apparatus comprising:

• an X-ray tube which is freely movable in at least one of a horizontal direction and a vertical direction;
• detection means, disposed in the vicinity of the X-ray detector, for detecting a dislocated degree of the focal spot position of the X-ray tube;
• and
• means for automatically controlling the focal spot position of the X-ray tube based on data obtained from the detection means so that the focal spot position of the X-ray tube remains fixed in a predetermined position,
• wherein the detection means includes a detection timing means for controlling an instance of detection and aligning the focal spot position by utilizing only an output of the X-ray amount detected at a predetermined position of a gantry.