1. A method of scanning a subject to be imaged, the method comprising: acquiring projection data from a first region of a pixel, wherein the first region has a first area; acquiring projection data from a second region of the pixel, wherein the second region has a second area; and calibrating a measured X-ray flux rate as a function of an incident flux rate for each of the first and second regions; correcting the projection data for the first and second regions of the pixel based upon the calibration; and combining the corrected projection data from the first and second regions to obtain composite projection data for the pixel.