Optimal number of pinholes in multi-pinhole SPECT for mouse brain imaging - a simulation study
Optimal number of pinholes in multi-pinhole SPECT for mouse brain imaging - a simulation study
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DOI：
10.1088/0031-9155/50/19/013
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发表时间：
2005-10-07
影响因子：
3.5
通讯作者：
Acton, PD
中科院分区：
文献类型：
--
作者：
Cao, ZX;Bal, G;Acton, PD
本研究模拟了多针孔单光子发射计算机断层扫描（SPECT）系统使用蒙特卡罗方法，并探讨了不同的多针孔设计定量小鼠脑成像。研究多针孔SPECT的先前方法通常不是最佳的，因为针孔的数量和几何布置通常是凭经验选择的。本研究旨在优化针孔的数量为一个给定的针孔安排，也为定量神经受体结合在小鼠大脑中的具体应用。使用基于蒙特卡罗模拟的分析方法生成各种计数水平的投影数据。一个三维有序子集的期望最大化算法被开发和用于重建图像，结合现实针孔模型的分辨率恢复和降噪。虽然重叠投影产生的伪影可能是多针孔重建中的主要问题，但与具有相同针孔直径的单针孔系统相比，冷棒体模研究显示多针孔系统的空间分辨率损失最小。使用小鼠脑模型和低活性（37 MBq）的神经受体结合位点的定量研究表明，多针孔系统优于单针孔系统，通过保持平均值和降低测量的摄取率的方差。多针孔准直可用于减少注射剂量，从而减少对动物的辐射暴露。结果还表明，本文所示的九针孔配置是一个很好的选择，小鼠脑成像。
This study simulates a multi-pinhole single-photon emission computed tomography (SPECT) system using the Monte Carlo method, and investigates different multi-pinhole designs for quantitative mouse brain imaging. Prior approaches investigating multi-pinhole SPECT were not often optimal, as the number and geometrical arrangement of pinholes were usually chosen empirically. The present study seeks to optimize the number of pinholes for a given pinhole arrangement, and also for the specific application of quantitative neuroreceptor binding in the mouse brain. An analytical Monte Carlo simulation based method was used to generate the projection data for various count levels. A three-dimensional ordered-subsets expectation-maximization algorithm was developed and used to reconstruct the images, incorporating a realistic pinhole model for resolution recovery and noise reduction. Although artefacts arising from overlapping projections could be a major problem in multi-pinhole reconstruction, the cold-rod phantom study showed minimal loss of spatial resolution in multi-pinhole systems, compared to a single-pinhole system with the same pinhole diameter. A quantitative study of neuroreceptor binding sites using a mouse brain phantom and low activity (37 MBq) showed that the multi-pinhole system outperformed the single-pinhole system by maintaining the mean and lowering the variance in the measured uptake ratio. Multi-pinhole collimation can be used to reduce the injected dose and thereby reduce the radiation exposure to the animal. Results also suggest that the nine-pinhole configuration shown in this paper is a good choice for mouse brain imaging.