Scatter correction techniques in 3D PET: a Monte Carlo evaluation

In this work a Monte Carlo software package, PET-EGS, designed to simulate realistic PET clinical studies, was used to assess three different approaches to scatter correction in 3D PET: analytical (gaussian fitting technique), experimental (dual energy window technique), probabilistic (Monte Carlo technique). Phantom and clinical studies were performed by 3D PET and simulated by PET-EGS. Clinical studies were simulated assuming PET emission/transmission multivolume images as voxelized source objects describing the distribution of both the radioactivity and attenuation coefficients and accounting for out-of-field activity and media. The accuracy of PET-EGS in modeling the physical response of a 3D PET scanner was assessed by statistical comparison between measured and total (scatter+unscatter) simulated distributions (probability for the two distributions to be the same distribution: p>0.95). The accuracy of the scatter models, for each scatter correction technique, was evaluated on sinograms by statistical comparison between the estimated and the simulated scatter distributions (agreement <1 /spl sigma/). The accuracy of scatter correction was evaluated on sinograms by comparison between scatter corrected and simulated unscatter distributions (residual scatter fraction <13 %).