A method for scanning an object to reduce image degradation includes scanning the object in a helical mode using a multi-slice CT imaging system having a plurality of detector arrays arranged along a z-axis direction and a radiation source having a beam focal spot. The method further includes wobbling the focal spot of the radiation source in the z-axis direction during the scanning to selectively preferentially illuminate individual detector arrays through the scanned object for each view. Data is collected from each detector array for each view only when the detector array from which data is being collected is selectively illuminated.