The ClearPET™ project: development of a 2nd generation high-performance small animal PET scanner

Abstract

Second generation high-performance PET scanners, called ClearPET™11ClearPET is a trademark of the Crystal Clear Collaboration., have been developed by working groups of the Crystal Clear Collaboration (CCC). High sensitivity and high spatial resolution for the ClearPET camera is achieved by using a phoswich arrangement combining two different types of lutetium-based scintillator materials: LSO from CTI and LuYAP:Ce from the CCC (ISTC project). In a first ClearPET prototype, phoswich arrangements of 8×8 crystals of 2×2×10mm3 are coupled to multi-channel photomultiplier tubes (Hamamatsu R7600). A unit of four PMTs arranged in-line represents one of 20 sectors of the ring design. The opening diameter of the ring is 120mm, the axial detector length is 110mm.The PMT pulses are digitized by free-running ADCs and digital data processing determines the gamma energy, the phoswich layer and even the exact pulse starting time, which is subsequently used for coincidence detection. The gantry allows rotation of the detector modules around the field of view.Preliminary data shows a correct identification of the crystal layer about (98±1)%. Typically the energy resolution is (23.3±0.5)% for the luyap layer and (15.4±0.4)% for the lso layer. early studies showed the timing resolution of 2ns FWHM and 4.8ns FWTM. the intrinsic spatial resolution ranges from 1.37mm to 1.61mm full-width of half-maximum (FWHM) with a mean of 1.48mm FWHM. further improvements in image and energy resolution are expected when the system geometry is fully modeled.