High-resolution cardiac rat SPECT: Effect of dose and acquisition time

SPECT imaging with low dose or short acquisition time can lead to very noisy reconstructed images. With the U-SPECT-II system we study the effect of low-count scans, and 3D Gaussian blurring to suppress statistical errors. Three different groups of short-time cardiac rat scans were derived from a long-time scan. Images were reconstructed and then smoothed with 3D Gaussian filters with different kernel sizes. We used the standard deviations of voxel values in the reconstructions from each short-time group to indicate the quality of the blurred images. The results show that a good cardiac rat SPECT image can be obtained from a scan in the U-SPECT-II system within very short time (2 minutes) or with very low dose (0.30 mCi activity injected) if some additional blurring is accomplished to the reconstruction.