A medical imaging system is provided that detects any change in relative position between the patient and the imaging device and corrects the image data for any motion that occurs. The medical imaging system includes: an imaging device for capturing two or more image data sets representative of a patient; a tracking subsystem for capturing patient position data that is indicative of the position of the patient and device position data that is indicative of the position of the imaging device; an image subtraction subsystem for performing a digital subtraction operation between at least two image data sets; and a motion correction subsystem configured to detect a change in the relative position between the patient and the imaging device and, upon detecting a change in the relative position, compensate in at least one of the first image data set and the second image data set for the change in relative position prior to performing the digital subtraction operation.