Patent ID: 7263157

Claim:
An imaging tomography apparatus comprising: a first data acquisition system disposed at a first system angle in an azimuthal direction, comprising a first radiation radiator that emits radiation passing through a measurement region and a first radiation detector that generates first detector output signals representing absorption of said radiation emitted by said first radiation radiator; a second data acquisition system disposed at a second system angle in said azimuthal direction, different from said first system angle, comprising a second radiation radiator that emits radiation passing through said measurement region and a second radiation detector that generates second detector output signals representing absorption of said radiation emitted by said second radiation radiator; said first data acquisition system and said second data acquisition system being mounted for rotation around a rotational axis common to both said first data acquisition system and said second data acquisition system; a reference object positionable at a reference position in said measurement region but outside of said rotational axis; and a calculation unit, supplied with said first detector output signals and said second detector output signals, that calculates, for each of a plurality of rotation angle positions of said first and second data acquisition systems with said first and second data acquisition systems being rotated at a substantially constant rotation angle speed, a first measurement value from said first detector output signals representing attenuation by said reference object of said radiation emanating from said first radiation radiator, and a second measurement value from said second detector output signals representing attenuation by said reference object of said radiation emanating from said second radiation radiator, and that determines the first and second system angles from said first and second measurement values for each of said plurality of rotation angle positions.