Design and initial results of an RF-penetrable TOF PET insert dedicated for brain PET/MRI

Combined PET/MRI allows physicians to acquire multiparametric (anatomical, functional and molecular) information about a patient's diseases in one imaging session. A PET insert dedicated to brain PET/MRI offers several advantages compared to the commercial integrated whole-body PET/MRI systems, including 2-3 times higher sensitivity, better spatial resolution, and significantly lower price. We are developing an RF-penetrable TOF PET insert dedicated for brain PET/MRI. The trans-axial field-of-view (FoV) of the scanner is 28 cm, and the axial FoV is 16 cm. The PET ring consists of 16 detector modules. Within each detector module, 6 sub-modules are arranged in the axial direction of the scanner. Each sub-module consists of an array of 8 x 16 LYSO crystals, each 3.2 mm x 3.2 mm x 20 mm, coupled one-to-one to an array of 8 x 16 SiPMs. Four PETA6 ASICs are placed on the sub-module to read out the signals from the SiPMs. Energy resolution at 511 keV and coincidence timing resolution (CRT) achieved in preliminary coincidence measurements acquired with two 4 x 4 LYSO crystal arrays are 12.3 ± 0.3% and 285 ± 14.0 ps FWHM, respectively. The sub-modules, with minimized trace length between the SiPMs and the PETA6 ASICs and active liquid cooling, are currently under production aiming for a system CRT goal of 250 ps FWHM. The 250 ps FWHM CRT goal will provide an image SNR gain of 2 from TOF, which will help to further enhance visualization and quantification of brain images. In this presentation, we will present the design and initial results of this new RF-penetrable TOF PET insert.