Monte Carlo simulations of a small-animal PET scanner. Analysis of performances and comparison between camera designs

The work analyzes the performances (scatter fraction, spatial resolution, sensitivity, image quality) obtained from a 10- detectors small-animal PET, simulated via Geant4 Application for Emission Tomography (GATE), in comparison with other camera designs. Particular attention is given to the comparison with the 12-detectors miniPET II, already built and working, with the ultimate goal to understand if the removal of two detectors would substantially affect performances. Results obtained show a clear improvement in count rate and scatter fraction (-4% with respect to miniPET II), as well as in sensitivity (maximum value obtained at the center of the camera with 10.91 cps/kBq); spatial resolution is as good as 1.58 mm FWHM in the transaxial plane, only 10% higher than miniPET II, and is confirmed by image quality tests on a mini Derenzo phantom. Results are encouraging and speak in favour of 10-detectors design