Variance propagation for SPECT with energy-weighted acquisition

The authors compare the noise characteristic of SPECT (single-photon-emission computed tomography) images which are reconstructed from data acquired by both EWA energy-weighted acquisition and normal windowed acquisition (NWA). The comparisons used are propagation of variance and measurement of the noise power spectrum (NPS). For a selected Tl-201 weighing function, the analytically predicted variance (neglecting covariance terms) was compared with the variance from experimental SPECT scans of a phantom. Reasonable agreement was observed between predicted and measured percent rms noise. The NPS for EWA was skewed slightly with respect to the NWA spectrum.<
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