INTERCOMPARISON OF 4 RECONSTRUCTION TECHNIQUES FOR POSITRON VOLUME IMAGING WITH ROTATING PLANAR DETECTORS

Four reconstruction techniques for positron volume imaging have been e valuated for scanners based on rotating planar detectors using measure d and simulated data. The four techniques compared are backproject the n filter (BPF), the 3D reprojection (3D RP) method for 3D filtered bac kprojection (FBP), Fourier rebinning (FORE) in conjunction with 2D FBP (FORE + 2D FBP) and 3D ordered subsets expectation maximization (3D O SEM). The comparison was based on image resolution and on the trade-of f between contrast and noise. In general FORE + 2D FBP offered a bette r contrast-noise trade-off than 3D RP, whilst 3D RP offered a better t rade-off than BPF. Unlike 3D RP, FORE + 2D FBP did not suffer any cont rast degradation effect at the edges of the axial field of view, but w as unable to take as much advantage from high-accuracy data as the oth er methods. 3D OSEM gave the best contrast at the expense of greater i mage noise. BPF, which demonstrated generally inferior contrast-noise behaviour due to use of only a subset of the data, gave more consisten t spatial resolution over the field of view than the projection-data b ased methods, and was best at taking full advantage of high-accuracy d ata.