Accurate Monte Carlo Modeling of Small-Animal Multi-Pinhole SPECT for Non-Standard Multi-Isotope Applications
Accurate Monte Carlo Modeling of Small-Animal Multi-Pinhole SPECT for Non-Standard Multi-Isotope Applications
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DOI：
10.1109/tmi.2021.3073749
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发表时间：
2021-09-01
影响因子：
10.6
通讯作者：
Brenner, Winfried
中科院分区：
文献类型：
--
作者：
Lukas, Mathias;Kluge, Anne;Brenner, Winfried
临床前 SPECT 仪器的最新进展使得能够在物理可行性的边缘进行非标准多同位素采集，从而提高药物研究的效率。由于应用的多样性，成像硬件、采集协议和重建算法的优化是一项核心且重复的任务。为此，我们开发了临床前最先进的多针孔 SPECT 系统 NanoSPECT/CTPLUS 的蒙特卡罗模拟模型，重点是在系统范围限制附近运行的多同位素实验的高精度。 GATE/GEANT4 模型包括对多针孔准直器和探测器后室的所有子结构的准确描述。读出电子器件采用多种信号处理器进行建模，部分扩展为包含非简化的测量响应函数。最终模型能够为标准和非标准多同位素实验高精度地预测能谱、平面图像和断层扫描重建。可以针对各种噪声水平和不同的角度欠采样模式再现复杂的活动分布。以双同位素三示踪剂实验为例，该模型已被证明是在多同位素多针孔 SPECT 性能范围限制下进行协议优化和定量图像校正的强大工具。
Recent advances in preclinical SPECT instrumentation enable non-standard multi-isotope acquisitions at the edge of physical feasibility to improve efficiency of pharmaceutical research. Due to the variety of applications, optimization of imaging hardware, acquisition protocols and reconstruction algorithms is a central and recurring task. For this purpose, we developed a Monte Carlo simulation model of a preclinical state-of-the-art multi-pinhole SPECT system, the NanoSPECT/CTPLUS, with emphasis on high accuracy for multi-isotope experiments operating near the system range limits. The GATE/ GEANT4 model included an accurate description of multi-pinhole collimators and all substructures of the detector back compartment. The readout electronics was modeled with a variety of signal processors partially extended to incorporate non-simplified measured response functions. The final model was able to predict energy spectra, planar images and tomographic reconstructions with high accuracy for both standard and non-standard multi-isotope experiments. Complex activity distributions could be reproduced for a wide range of noise levels and different modes of angular undersampling. Using the example of a dual-isotope triple-tracer experiment, the model has proven to be a powerful tool for protocol optimization and quantitative image correction at the performance range limits of multi-isotope multi-pinhole SPECT.