A Monte Carlo investigation of the spatial resolution performance of a small-animal PET scanner designed for mouse brain imaging studies.
A Monte Carlo investigation of the spatial resolution performance of a small-animal PET scanner designed for mouse brain imaging studies.
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DOI：
10.1016/j.ejmp.2013.03.004
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发表时间：
2014-02
期刊：
影响因子：
--
通讯作者：
Cherry SR
中科院分区：
文献类型：
--
作者：
Rodríguez-Villafuerte M;Yang Y;Cherry SR
我们的实验室已经开发出PET探测器，其深度编码精度为~2 mm，基于具有锥形几何形状的精细像素化晶体，在两端使用位置敏感雪崩光电二极管（PSAPD）进行读出。这些探测器目前正在我们的实验室中使用，以建立一个单环高分辨率PET扫描仪的小鼠脑成像研究。由于PSAPD周围的无效区域，检测器模块之间存在较大的间隙，这会降低使用滤波反投影（FBP）的分析重建获得的图像空间分辨率。在这项工作中，基于Geant 4的GATE蒙特卡罗软件包被用来帮助确定机架旋转是否是必要的，并评估系统的预期空间分辨率。研究了以下因素：使用离散余弦变换（DCT）方法补偿和不补偿缺失数据的旋转与静态机架模式、两级深度编码和18 F的正电子湮灭效应。我们的研究结果表明，虽然静态扫描仪产生的条纹和环形伪影质量差的FBP图像，图像质量得到了很大的改善后，补偿丢失的数据。模拟结果表明，由于正电子射程、光子非共线性和探测器物理尺寸的影响，系统的空间分辨率达到了0.70 ± 0.05 mm，接近于0.5 mm的极限值。我们的结论是，良好的重建分辨率没有机架旋转是可能的，即使使用FBP，如果间隙得到适当的处理，这种设计可以接近正电子湮没物理设置的分辨率限制。
Our laboratory has developed PET detectors with depth-encoding accuracy of ~2 mm based on finely pixelated crystals with a tapered geometry, readout at both ends with position-sensitive avalanche photodiodes (PSAPDs). These detectors are currently being used in our laboratory to build a one-ring high resolution PET scanner for mouse brain imaging studies. Due to the inactive areas around the PSAPDs, large gaps exist between the detector modules which can degrade the image spatial resolution obtained using analytical reconstruction with filtered backprojection (FBP). In this work, the Geant4-based GATE Monte Carlo package was used to assist in determining whether gantry rotation was necessary and to assess the expected spatial resolution of the system. The following factors were investigated: rotating vs. static gantry modes with and without compensation of missing data using the discrete cosine transform (DCT) method, two levels of depth-encoding, and positron annihilation effects for 18F. Our results indicate that while the static scanner produces poor quality FBP images with streak and ring artifacts, the image quality was greatly improved after compensation of missing data. The simulation indicates that the expected FWHM system spatial resolution is 0.70 ± 0.05 mm, which approaches the predicted limit of 0.5 mm FWHM due to positron range, photon non-colinearity and physical detector element size effects. We conclude that excellent reconstructed resolution without gantry rotation is possible even using FBP if the gaps are appropriately handled and that this design can approach the resolution limits set by positron annihilation physics.
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影响因子：
3.5
作者：
St James S;Yang Y;Bowen SL;Qi J;Cherry SR
通讯作者：
Cherry SR
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作者：
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Cherry SR
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作者：
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