A SPECT study is carried out on a patient's body organ, such as the heart, and frames of image data are thereby acquired. The image data in these frames are subjected to a series of mappings and computations, from which frames containing a significant quantity of organ motion can be identified....http://www.google.co.uk/patents/US5758645?utm_source=gb-gplus-sharePatent US5758645 - Automatic detection and correction of body organ motion and particularly cardiac motion in nuclear medicine studies 
