Reconstruction of dynamic gated cardiac SPECT

In this paper we propose an image reconstruction procedure which aims to unify gated SPECT and dynamic SPECT into a single method. We will divide the cardiac cycle into a number of gate intervals as in gated SPECT, but treat the tracer distribution for each gate as a time-varying signal. By using dynamic expectation maximization and motion-compensated temporal regularization, our reconstruction procedure will produce an image sequence that shows both cardiac motion and time-varying tracer distribution simultaneously. To demonstrate the proposed reconstruction methods, we simulated gated cardiac perfusion imaging using the gated mathematical cardiac-torso (gMCAT) phantom with Tc99m-Teboroxime dynamics. Our preliminary results show that the proposed methods can produce more accurate reconstruction of gated dynamic images than independent reconstruction of individual gate frames with spatial smoothness alone.