Initial Results of the MINDView PET Insert Inside the 3T mMR
Initial Results of the MINDView PET Insert Inside the 3T mMR
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DOI：
10.1109/trpms.2018.2866899
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发表时间：
2019-05-01
影响因子：
4.4
通讯作者：
Benlloch, Jose M.
中科院分区：
文献类型：
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作者：
Gonzalez, Antonio J.;Gonzalez-Montoro, Andrea;Benlloch, Jose M.
混合分子和解剖成像设备，特别是当同时工作时，已显示出比顺序采集更具优势。具体地说，在这项初步研究中，我们介绍了3T磁共振成像(MRI)系统中脑正电子发射断层扫描(PET)插入物的工作性能。据我们所知，这是基于整体Lyso块的最大的PET系统。它由60块50 mm×50 mm×20 mm的闪烁体组成，分成3个环，每个环20个探测器模块。定义了直径240 mm、轴向154 mm的有效视场。这些晶体在入射面包括一个后向反射层，并被耦合到定制的12×12硅光电倍增管(SiPM)阵列，每个阵列3 mm x 3 mm。前端电子设备通过对SiPM阵列的每一行和每列进行采样来提供闪烁光的X和Y投影。通过使用温度控制的空气将镶件热稳定到约27摄氏度。PET镶件已安装在慕尼黑Klinikum rechts der Isar(慕尼黑)，并在西门子Bioggraph MMR全身扫描仪中进行测试，这是一台3T磁共振成像与PET扫描仪相结合的仪器。用位于视场中心的小尺寸源(CFOV)测量了350-650keV能量窗的系统灵敏度约为7%。目前的系统评估显示，使用迭代算法在CFOV处的空间分辨率为1.7 mm，在中心直径120 mm的范围内低于2 mm。一个2.5 mm的小DeRenzo模型的杆状清晰可分辨，不依赖于所有测试的MRI序列，包括回波平面成像、超短时间回波、MPRAGE和T2-FLAIR或动脉自旋标记。在这些序列下，对于各种MR成像采集，PET插入物也没有表现出任何计数率退化。
Hybrid molecular and anatomical imaging devices, especially when simultaneously working, have shown to provide advantages over sequential acquisitions. In particular, we present in this preliminary study, the working performance of a brain positron emission tomography (PET) insert, within a 3T magnetic resonance imaging (MRI) system. To our knowledge, this is the largest PET system based on monolithic LYSO blocks. It consists of 60 scintillator blocks of 50 mm x 50 mm x 20 mm arranged in 3 rings of 20 detector modules each. An effective field of view (FOV) of 240 mm in diameter and 154 mm axially is defined. The crystals included a retroreflector layer at the entrance face, and are coupled to custom arrays of 12 x 12 silicon photomultipliers (SiPM), 3 mm x 3 mm each. Frontend electronics provide X and Y projections of the scintillation light by sampling each row and column of the SiPM arrays. The insert is thermally stabilized by using temperature-controlled air to about 27 degrees C. The PET insert has been installed at the Klinikum rechts der Isar (Munich) and tested within the whole-body Siemens biograph mMR, a 3T MRI combined with a PET scanner. A system sensitivity of almost 7% for an energy window of 350-650 keV was measured using a small size source at the center of the FOV (CFOV). Current system evaluation showed a spatial resolution at the CFOV of 1.7 mm using iterative algorithms, being below 2 mm within a centered diameter of 120 mm. Rods of a small Derenzo phantom of 2.5 mm were clearly resolved, independently of all tested MRI sequences including echo-planar imaging, ultrashort time echo, MPrage, and T2-flair or arterial spin labeling. The PET insert did not show any count rate degradation also under those sequences for a variety of MR imaging acquisitions.