%0 Journal Article %A Shuguang Chen %A Tuoyu Cao %A Yun Dong %A Shitao Liu %A Gang Yang %A Yong Zhao %A Xin Chen %A Lingzhi Hu %A Hongcheng Shi %T NEMA NU2-2012 Performance Measurements of the United-Imaging uPMR790: A HD TOF Simultaneous PET/MR System %D 2018 %J Journal of Nuclear Medicine %P 215-215 %V 59 %N supplement 1 %X 215Objectives: The United-Imaging uPMR790 is a clinical integrated whole body Time-of-Flight (TOF) PET/MR scanner from Shanghai United Imaging Healthcare Co. The system is capable of simultaneous PET and MRI acquisition with 450ps time resolution, world’s highest 2.8 mm spatial resolution (at the center of FOV with NEMA standard) and world’s longest 32cm axial field of view. The high definition digital PET detector enhances small lesions detectability and improves quantification accuracy by reducing partial volume effect. The long axial coverage provides streamlined whole-body workflow by reducing the total number of bed stations. Only two other whole body simultaneous PET/MR systems had been reported so far due to unique technical challenges such as electromagnetic interference between MRI and PET subsystems. In this work, the United-Imaging uPMR790 was fully evaluated for the first time and the effects of interference from MR operation. Materials and Methods:NEMA performance measurement was performed on the newly installed United-Imaging uPMR790 PET/MR scanner at Shanghai Zhongshan hospital. The uPMR790 system comprises a 3T super conducting magnet, a gradient system with a set of second order active shimming coil (50mT/s, 200T/m/s), and a 48 channel radio frequency (RF) receiving system. The PET detector system is installed between the gradient coil and body coil. The entire PET ring comprises 20 modules with a transverse field of view of 60cm and an axial field of view of 32cm. Each module contains 5×14 blocks with 14 blocks along the axial direction. And each block has 4 SiPM detector channels coupled with a 7×8 array of 15.5×2.76×2.76 mm3 LYSO crystals through proprietary design of internal light guide. The entire system comprises 112 rings and each ring contains 700 crystal channels, making 78400 crystal channels in total. The PET system performance was evaluated following the NEMA NU2-2012 standards. Data acquisition was performed in the absence and presence of continuous MR pulsing during the entire data acquisition. A two point DIXON sequence, which is the sequence for PET attenuation correction was used. The RF power level was set to 400V, similar to the situation of a normal whole body MR scan. In addition, to evaluate the performance under extreme situations, image quality was tested under an extra set of MR sequences, including Echo Planar Imaging (EPI) and Single Shot Fast Spin Echo (SSFSE). All measurements was conducted at Shanghai Zhongshan Hospital. The system was fully calibrated and a quality assurance test was done before each NEMA measurement. Results: Image Quality results are shown in Table 1. Spatial Resolution (FWHM/mm) results are shown in Table 2. Clinical Images are shown in Figure 1. Conclusions: NEMA measurement demonstrates consistent ideal image contrast recovery and spatial resolution. Results with MRI pulsing reveal no PET image quality degradation during MR pulsing. The system achieves superior PET/MR imaging quality, fusion accuracy and accelerated workflow in clinical settings. %U