Investigation of analog charge multiplexing schemes for SiPM based PET block detectors
Investigation of analog charge multiplexing schemes for SiPM based PET block detectors
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DOI：
10.1088/0031-9155/58/11/3943
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发表时间：
2013-06-07
影响因子：
3.5
通讯作者：
Peng, Hao
中科院分区：
文献类型：
--
作者：
Downie, Evan;Yang, Xin;Peng, Hao
减少像素化正电子发射断层摄影（PET）探测器中的输出通道的数量是最小化成本和复杂性同时最小化对探测器性能的影响的有效方式。本文通过仿真和实验研究，从空间、时间和能量分辨率方面比较了两种复用方案的系统性能。使用SPICE环境进行模拟，以研究由此产生的洪水直方图和上升边缘斜率的差异。使用耦合到SensL ArraySL-4硅光电倍增管（SiPM）的氧硅酸镥钇（LYSO）晶体进行实验，该硅光电倍增管连接到包含两个感兴趣的多路复用方案的可互换电路板。测试了三种晶体配置：单晶元件（3 × 3 × 20 mm（3））、2 × 2阵列（晶体间距：3 × 3 × 20 mm（3））和6 × 6阵列（晶体间距：2.1 × 2.1 × 20 mm（3））。模拟结果与实验结果吻合较好。发现与电阻复用（平均1.95 +/-0.03ns和3.33 +/-0.10ns）相比，电容复用能够实现良好均匀性（阵列的平均值分别为1.11 +/-0.01ns和1.90 +/-0.03ns）和晶体分离的改进的时间分辨率。另一方面，电阻式多路复用展示出略微改进的能量分辨率（11 +/-0.1%和22 +/-0.6%，相比之下，电容式阵列为12 +/-0.1%和24 +/-0.4%），这被认为是由在分裂电容器与放大器的输入阻抗之间形成的RC电路引起的。本文还讨论了这项工作与使用SiPM阵列的PET块检测器设计的相关性，包括SiPM像素之间的光共享、边缘压缩和增益变化。
Reducing the number of output channels in pixelated positron emission tomography (PET) detectors is an effective way to minimize cost and complexity while minimizing the impact on detector performance. This paper compares the system performance of two multiplexing schemes by using both simulation and experimental studies, with respect to spatial, time and energy resolutions. Simulations were performed using the SPICE environment to investigate differences in resulting flood histograms and rising edge slopes. Experiments were performed using lutetium-yttrium oxyorthosilicate (LYSO) crystals coupled to a SensL ArraySL-4 silicon photomultiplier (SiPM) connected to interchangeable circuit boards containing the two multiplexing schemes of interest. Three crystal configurations were tested: a single crystal element (3 x 3 x 20 mm(3)), 2 x 2 array (crystal pitch: 3 x 3 x 20 mm(3)) and 6 x 6 array (crystal pitch: 2.1 x 2.1 x 20 mm(3)). Good agreement was found between the simulations and experiment results. It is found that the capacitive multiplexing is able to achieve an improved time resolution of good uniformity (average of 1.11 +/- 0.01 ns and 1.90 +/- 0.03 ns for the arrays, respectively) and crystal separation, compared to the resistive multiplexing (average of 1.95 +/- 0.03 ns and 3.33 +/- 0.10 ns). On the other hand, the resistive multiplexing demonstrates slightly improved energy resolution (11 +/- 0.1% and 22 +/- 0.6%, compared to 12 +/- 0.1% and 24 +/- 0.4% for the capacitive array), which is believed to be caused by the RC circuit formed between the splitting capacitors and the input impedance of amplifiers. The relevancy of this work to the PET block detector design using SiPM arrays is also discussed, including light sharing, edge compression and gain variation among SiPM pixels.