Fast dynamic image reconstruction for gated cardiac SPECT

In this paper we propose a fast image reconstruction procedure for dynamic images from gated SPECT acquisition. We 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. To speed up the reconstruction procedure, we derive an ordered-subset version of the dynamic expectation-maximization (dEM) algorithm, and apply motion-compensated temporal filtering to enforce the correlation among the different gates. We simulated gated cardiac perfusion imaging using the gated mathematical cardiac-torso(gMCAT) phantom with Tc99m-Teboroxime dynamics. Our experimental results demonstrate that the proposed method can reconstruct gated dynamic images faster than the regular dEM algorithm, and that temporal smoothing is more effective than spatial smoothing for noise reduction.