Three-dimensional restoration of single photon emission computed tomography images

A 3-D filter was used for restoring SPECT (single photon emission computed tomography) images. The 3-D filter is shown to perform better than 2-D methods because it takes into consideration the interslice information in the filtering process and has a relatively space-invariant blur function. The potential of 3-D Wiener and power spectrum equalization filters was investigated. These filters were applied to SPECT images of a large, truncated conic phantom containing two types of cold spots, a sphere, and a triangular prism. The images were acquired on an ADAC GENESYS camera. A comparison was performed between results obtained in this study and those obtained by 2-D pre-reconstruction restoration and 2-D post-reconstruction restoration filters. Quantitative analysis of the 3-D restored images performed through measurement of root-mean-square errors and contrast ratios shows a considerable reduction in error and increase in contrast over images restored using the two other methods.<>