Partial volume correction in SPECT using anatomical information and iterative FBP

The ability to correctly quantify activity concentration with single photon emission computed tomography (SPECT) is limited by its spatial resolution. Blurring of data between adjacent structures, which is known as partial volume effects, can be compensated for by utilizing high resolution structural information from other imaging modalities such as CT or MRI. Previously developed partial volume correction (PVC) methods normally assume a spatially invariant point spread function. In SPECT this is not a good approximation, since the resolution varies with the distance from the collimator. A new method, p-PVC, was developed in this paper, which takes into account the distance dependent blurring. The method operates in projection space and is combined with filtered back-projection (FBP) reconstruction. Results from simulations show that similar quantitative results could be obtained with p-PVC+FBP as with OSEM EM with resolution recovery, although with better structural definition and an order of magnitude faster.