Evaluation of event position reconstruction in monolithic crystals that are optically coupled.
Evaluation of event position reconstruction in monolithic crystals that are optically coupled.
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DOI：
10.1088/0031-9155/61/23/8298
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发表时间：
2016-12-07
影响因子：
3.5
通讯作者：
Miyaoka RS
中科院分区：
文献类型：
--
作者：
Morrocchi M;Hunter WC;Del Guerra A;Lewellen TK;Kinahan PE;MacDonald LR;Bisogni MG;Miyaoka RS
正开发一种以伪单片晶体为特征的PET探测器，作为全单片晶体PET探测器的更具成本效益的替代方案。这项工作评估了不同的方法来本地化的闪烁事件在四分之一的单片晶体，光耦合。使用四个26 × 26 × 10 mm 3 LYSO晶体形成半单片晶体组件，该晶体使用光学粘合剂光学耦合在一起，以模拟52 × 52 × 10 mm 3单片晶体检测器。晶体组件耦合到一个64通道多阳极光电倍增管使用硅脂。使用34 × 34扫描网格校准检测器。事件首先被过滤，并使用多洛伦兹拟合到收集的光分布进行深度分离。接下来，探索了三种不同的技术来生成用于事件定位的查找表。第一种技术是跨界面的“标准插值”。第二种技术是“中心外推”，其中将箱放置在界面的中点处，并且丢弃位于界面区域内的事件。第三种技术使用了一个“中心重叠”的方法，其中一个扩展的区域外推在每个接口。然后使用最小二乘最小化和最大似然方法定位事件。最小二乘最小化应用到查找表产生的标准插值技术具有最好的半高全宽（FWHM）的固有空间分辨率和最低的偏差。然而，事件定位中存在不连续性，这很可能导致重建图像中的伪影。中心外推技术也有不连续性和30%的灵敏度损失附近的晶体-晶体界面。中心重叠技术的性能指标略有下降，但它仍然提供了约2.1毫米的内在空间分辨率在晶体-晶体界面，并具有对称和连续变化的响应函数。对于中心重叠数据，使用最大似然定位的结果与最小二乘最小化相似。
A PET detector featuring a pseudo-monolithic crystal is being developed as a more cost-effective alternative to a full monolithic crystal PET detector . This work evaluates different methods to localize the scintillation events in quartered monolithic crystals that are optically coupled. A semi-monolithic crystal assembly was formed using four 26 × 26 × 10 mm3 LYSO crystals optically coupled together using optical adhesive, to mimic a 52 × 52 × 10 mm3 monolithic crystal detector. The crystal assembly was coupled to a 64-channel multi-anode photomultiplier tube using silicon grease. The detector was calibrated using a 34 × 34 scan grid. Events were first filtered and depth separated using a multi-Lorentzian fit to the collected light distribution. Next, three different techniques were explored to generate the look up tables for the event positioning. The first technique was 'standard interpolation' across the interface. The second technique was 'central extrapolation', where a bin was placed at the midpoint of the interface and events positioned within the interface region were discarded. The third technique used a 'central overlap' method where an extended region was extrapolated at each interface. Events were then positioned using least-squares minimization and maximum likelihood methods. The least-squares minimization applied to the look up table generated with the standard interpolation technique had the best full width at half maximum (FWHM) intrinsic spatial resolution and the lowest bias. However, there were discontinuities in the event positioning that would most likely lead to artifacts in the reconstructed image. The central extrapolation technique also had discontinuities and a 30% sensitivity loss near the crystal-crystal interfaces. The central overlap technique had slightly degraded performance metrics, but it still provided ~2.1 mm intrinsic spatial resolution at the crystal-crystal interface and had a symmetric and continuously varying response function. Results using maximum likelihood positioning were similar to least-squares minimization for the central overlap data.
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影响因子：
3.5
作者：
Ling, T.;Lewellen, T. K.;Miyaoka, R. S.
通讯作者：
Miyaoka, R. S.
影响因子：
1.8
作者：
Lerche, CW;Benlloch, JM;Martínez, J
通讯作者：
Martínez, J
影响因子：
1.8
作者：
Ling, Tao;Lee, Kisung;Miyaoka, Robert S.
通讯作者：
Miyaoka, Robert S.
影响因子：
2.9
作者：
Lopes, MI;Chepel, V
通讯作者：
Chepel, V
影响因子：
1.8
作者：
Hunter WC;Barrett HH;Furenlid LR
通讯作者：
Furenlid LR