represents a worst case condition when scanning an object with a cyclic motion not necessarily periodic the motion artifact is minimum when the object is roughly in the same motion state at the start and end of the scan it is known that when the period of the motion matches exactly the cycle of the gantry speed for a half scan and a full scan the motion artifact is minimal to minimize motion artifacts a starting projection view is determined after collecting a plurality of projection views 52 the differences between the first and the last views used in the reconstruction are determined and the starting view selected is the one which minimizes the difference for example to find the starting angle for a halfscan to minimize motion induced artifacts a differential projection 54 is determined by the following relationship where u03b2 is the projection angle u03b3 is the detector angle and u03b3 m is the maximum detector angle for a full scan a differential projection 54 is determined by the following relationship to minimize the influence of other motion induced differences e g such as respiratory motion the differential projection is multiplied by a weighting function 56 an inconsistency index 58 u03be u03b2 is determined according to the following relationship where d u03b3 u03b2 is a differential projection u03c9 u03b3 is a weighting function u03b3 m is a maximum detector angle and u2212 u03b3 m is a minimum detector angle the diastole and systole phases of the heart are determined.