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Objective: We have tested the feasibility of applying an approximate three-dimensional (3D) reconstruction algorithm, the single slice rebinning method followed by standard 2D filtered back-projection (SSRB), to human basal ganglia studies. Such an approximate algorithm solves the problem of long reconstruction times and large dataset size associated with mathematically correct 3D reconstruction algorithms., Materials and Methods: First, recovery achieved when images were reconstructed with the SSRB method was compared with that achieved when a mathematically correct 3D reconstruction algorithm (3D method) was used with a series of spherical phantom studies. The SSRB method was then applied to 14 human receptor studies and the images compared with those obtained with the 3D method. The striatum/background contrast dependence of the SSRB method performance was tested by extending the comparison of the two reconstruction methods to single frames of two dynamic scanning sequences., Results: There was no significant visual difference in the human images obtained with the two methods and a quantitative striatal/cortical activity ratio analysis showed a contrast decrease of approximately 3% for the SSRB method. The analysis of the dynamic sequence did not show any contrast dependence of the SSRB method performance., Conclusion: The SSRB method was found adequate for processing data related to human striatal imaging for this particular tomograph geometry.

An algorithm is described for three-dimensional (3D) image reconstruction in positron volume imaging (PVI) using the inversion of the 3D radon transform (RT) for a truncated cylindrical detector geometry. A discrete version of the 3D RT is formed in a 3D histogram from the event-line coordinates of the detected events. The histogram entries represent the plane integrals of the activity in the field of view. Conventional inversion of the x-ray transform (XT) excludes oblique events in non-iterative reconstruction methods. by employing a spatially varying angular acceptance of events into the histogrammed plane integrals of the 3D RT, it is possible to include most of the detected oblique events in the reconstruction of the image using the standard 3D RT inversion formula. the oblique events are added to the histogram with a partial weight compared to those in complete (XT) projections. This single-pass reconstruction image has better statistical noise properties than images formed by RT inversion from complete XT projections, but only for some detector geometries is it significantly better. Monte Carlo simulations were used to study the statistical noise in images reconstructed using the new algorithm. The inherent difference in the axial versus the transaxial statistical noise in images reconstructed from truncated detectors is noted and is found to increase by including oblique events with this new algorithm.