Multiscale optical flow based respiratory motion correction in cardiac PET/CT

Gating The breathing cycle was divided into eight parts by using a respiratory signal. This signal was acquired by laying a belt around the patient's waist with a black disc containing a white spot in the center. The position of this spot was tracked with the help of a video camera. A light emitting diode (LED) was used for synchronizing the respiratory signal with the listmode PET data. The PET data is then sorted based upon the amplitude of the respiratory signal. Detailed comparison of different gating methods have shown that the amplitude based gating is superior to other forms of gating. The eight gates, which represent eight respiratory phases, are then reconstructed individually without attenuation correction.