Experimental setup for very high resolution animal PET based on solid state detector

A very high resolution animal PET instrument was investigated using Monte Carlo simulations. The instrument consists of an outer cylindrical BGO scintillation detector surrounding an inner cylindrical solid state detector composed of 0.3 mm square silicon pads. The interaction point of gamma rays that scatter in the pad detector can be accurately localized in 3D to within the pad volume. Total energy is known from the summed energy in silicon and BGO detectors. Simulation results show 192 μm spatial resolution for events in which both annihilation photons scatter in silicon detectors. We have constructed a prototype Compton PET instrument using two silicon detectors with 1.4 mm square pads, two CCDAQ data acquisition units that have digital signal processors, a source turntable, and a coincidence unit. Using this experimental setup the energy spectrum of photons from technetium (Tc-99m) was acquired with 2.45 keV energy resolution and the timing spectrum of annihilation photons from fluorine (F-18) was obtained with 1.9 ns timing resolution. This experimental, setup will be used to verify the simulation results for the high resolution PET that is expected to have a maximum resolution of 0.7 mm FWHM at the center of the field of view.