Abstract
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Objectives: Spatial resolution recovery (SRR) for SPECT has been frequently performed by incorporating the point spread function (PSF) in an iterative reconstruction. In the case of scintillation detector SPECT systems, the PSF is well approximated by the Gaussian function. The advantage of using the Gaussian PSF is the small computation time of forward and back projections in an iterative reconstruction. On the other hand, it is unknown whether the PSF in the pixelated CdTe detector SPECT system can be approximated by the Gaussian PSF. The aim of this study was to evaluate the feasibility of SRR using the Gaussian PSF (SRR-G) for the pixelated CdTe detector SPECT.
Methods: In order to compare the ability of SRR-G with SRR using realistic PSFs, we generated non-Gaussian PSFs of the pixelated detector SPECT by 3D simulation including a geometric array of the camera, the effect of discrete signal sampling, and septal penetration. Measurements of a phantom with hot spheres and rabbit with 99mTc-MDP were performed to evaluate SRR-G and SRR using simulated PSF (SRR-S).
Results: According to our phantom study, both SRR-G and SRR-S yielded much higher recovery coefficients compared to no SRR (79, 78 and 48 % for 10-mm-diameter sphere with SRR-G, SRR-S and no SRR, respectively). The bone image qualities of rabbit obtained with SRR-G were comparable to those obtained with SRR-S.
Conclusions: By using Gaussian PSF in SRR, we can take advantage of the high intrinsic resolution of the pixelated CdTe detector SPECT at a small computation cost.
- Society of Nuclear Medicine, Inc.