Initial Results of Simultaneous PET/MRI Experiments with an MRI-Compatible Silicon Photomultiplier PET Scanner
Initial Results of Simultaneous PET/MRI Experiments with an MRI-Compatible Silicon Photomultiplier PET Scanner
复制标题
DOI：
10.2967/jnumed.111.097501
复制
发表时间：
2012-04-01
影响因子：
9.3
通讯作者：
Lee, Jae Sung
中科院分区：
文献类型：
--
作者：
Yoon, Hyun Suk;Ko, Guen Bae;Lee, Jae Sung
目前研究最多的用于核磁共振兼容PET探测器的半导体光传感器是雪崩光电二极管（APD）。然而，硅光电倍增管（SiPM），又称盖格模式光电倍增管（APD），在下一代PET/MRI系统的开发中越来越受到关注，因为SiPM具有比APD更好的性能。我们开发了一种基于多通道SiPM阵列的MRI兼容PET系统，允许同时进行PET/MRI。方法：SiPM PET扫描仪由12个检测器模块组成，环形直径13.6 cm，轴向范围3.2 cm。在每个探测器模块中，4个多通道SiPM阵列（其中4 × 4通道排列在2 × 2阵列中以产生8 × 8通道）与20 × 18个Lu1.9Gd0.1SiO5:Ce晶体（每个晶体为1.5 × 1.5 × 7mm）耦合并安装在电荷分网上，用于将64个信号复用为4个位置信号。每个检测器模块都被封闭在屏蔽盒中，以减少PET和MRI扫描仪之间的干扰，并监测屏蔽盒内的温度，以校正SiPM的温度依赖性增益变化。PET探测器信号被传送到核磁共振室外部，并通过基于现场可编程门阵列的数据采集系统进行处理。MRI兼容性测试和同时进行PET/MRI采集在3-T临床MRI系统内进行，该系统具有内置在SiPM PET扫描仪中的4厘米环形接收器线圈。研究了成像系统之间的干扰，并进行了幻影和小鼠实验。结果：PET/MRI同时扫描时，PET信号无射频干扰，能谱和洪泛图无衰减。有或没有操作PET的MRI扫描质量仅显示轻微的退化。幻影和小鼠实验的结果证实了该系统同时用于PET/MRI的可行性。结论：基于sipm的多通道PET扫描仪可以同时进行PET/MRI， PET信号或图像没有射频干扰，MRI扫描结果只有轻微的退化。
The most investigated semiconductor photosensor for MRI-compatible PET detectors is the avalanche photodiode (APD). However, the silicon photomultiplier (SiPM), also called the Geiger-mode APD, is gaining attention in the development of the next generation of PET/MRI systems because the SiPM has much better performance than the APD. We have developed an MRI-compatible PET system based on multichannel SiPM arrays to allow simultaneous PET/MRI. Methods: The SiPM PET scanner consists of 12 detector modules with a ring diameter of 13.6 cm and an axial extent of 3.2 cm. In each detector module, 4 multichannel SiPM arrays (with 4 x 4 channels arranged in a 2 x 2 array to yield 8 x 8 channels) were coupled with 20 x 18 Lu1.9Gd0.1SiO5:Ce crystals (each crystal is 1.5 x 1.5 x 7 mm) and mounted on a charge division network for multiplexing 64 signals into 4 position signals. Each detector module was enclosed in a shielding box to reduce interference between the PET and MRI scanners, and the temperature inside the box was monitored for correction of the temperature-dependent gain variation of the SiPM. The PET detector signal was routed to the outside of the MRI room and processed with a field programmable gate array-based data acquisition system. MRI compatibility tests and simultaneous PET/MRI acquisitions were performed inside a 3-T clinical MRI system with 4-cm loop receiver coils that were built into the SiPM PET scanner. Interference between the imaging systems was investigated, and phantom and mouse experiments were performed. Results: No radiofrequency interference on the PET signal or degradation in the energy spectrum and flood map was shown during simultaneous PET/MRI. The quality of the MRI scans acquired with and without the operating PET showed only slight degradation. The results of phantom and mouse experiments confirmed the feasibility of this system for simultaneous PET/MRI. Conclusion: Simultaneous PET/MRI was possible with a multichannel SiPM-based PET scanner, with no radiofrequency interference on PET signals or images and only slight degradation of the MRI scans.