Calibration method for use in ct imaging

A device for determining calibration status of x-ray tube point sources within a dual point source computed tomography (CT) acquisition apparatus, comprising:

• a memory that stores a plurality of instructions;
• and
• a processor coupled to the memory and configured to execute the plurality of instructions to:
• receive dual point source CT data comprising x-ray detector measurement data for each of a series of x-ray projections, the measurement data corresponding to measurement data acquired with an x-ray generator of the CT acquisition apparatus providing alternately activated first and second x-ray point sources, the point sources displaced relative to one another along an orbital rotational axis of the generator within the CT acquisition apparatus, and wherein the measurement data includes for each x-ray projection a 2D attenuation pattern corresponding to measured attenuation values for a 2D array of detector elements;
• perform a point source calibration check that includes:
• determining, using the measurement data, a shift of the whole or part of the attenuation pattern of a first and second consecutive projection, each of the first and second projection generated using a different one of the two point sources;
• and
• determining whether the shift is within a pre-defined expected range.