Estimation of rigid-body and respiratory motion of the heart for SPECT motion correction

Motion of patients undergoing cardiac SPECT perfusion imaging causes artifacts in the acquired images which may lead to difficulty in interpretation. Our work investigates the technique of obtaining patient motion estimates from retro-reflective markers on stretchy bands wrapped around the chest and abdomen of subjects when they are imaged. Motion signals obtained from the markers consist of at least two components, rigid body motion (RBM) and respiratory motion (RM). In this paper an improved method of separation of the marker motion signals into the two components, RBM and RM is reported. Motion studies of rigid-tool, volunteers and patients are used to evaluate the method and preliminary estimates of the motion of the heart due to patient movement and respiration are obtained.