Arterial sampling in PET studies for the purposes of kinetic modeling remains an invasive, time-intensive, and expensive procedure. Alternatives to derive the blood time-activity curve (BTAC) non-invasively are either reliant on large vessels in the field of view or are laborious to implement and analyze as well as being prone to many processing errors. An alternative method is proposed in this work by the simulation of a non-invasive coincidence detection unit. We utilized GATE simulations of a human forearm phantom with a blood flow model, as well as a model for dynamic radioactive bolus activity concentration based on clinical measurements. A fixed configuration of 14 and, also separately, 8 detectors were employed around the phantom, and simulations were performed to investigate signal detection parameters. Bismuth germanate (BGO) crystals proved to show the highest count rate capability and sensitivity to a simulated BTAC with a maximum coincidence rate of 575 cps. Repeatable location of the blood vessels in the forearm allowed a half-ring design with only 8 detectors. Using this configuration, maximum coincident rates of 250 cps and 42 cps were achieved with simulation of activity concentration determined from 15O and 18F arterial blood sampling. NECR simulated in a water phantom at 3 different vertical positions inside the 8-detector system (Y = − 1 cm, Y = − 2 cm, and Y = −3 cm) was 8360 cps, 13,041 cps, and 20,476 cps at an activity of 3.5 MBq. Addition of extra axial detection rings to the half-ring configuration provided increases in system sensitivity by a factor of approximately 10. Initial simulations demonstrated that the configuration of a single half-ring 8 detector of monolithic BGO crystals could describe the simulated BTAC in a clinically relevant forearm phantom with good signal properties, and an increased number of axial detection rings can provide increased sensitivity of the system. The system would find use in the derivation of the BTAC for use in the application of kinetic models without physical arterial sampling or reliance on image-based techniques.

中文翻译：

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用于无创确定动脉血液时间-活动曲线测量值的重合检测系统的仿真研究。

为了动力学建模的目的，PET研究中的动脉采样仍然是一种侵入性，耗时且昂贵的程序。非侵入性地得出血液时间-活动曲线（BTAC）的替代方法要么依赖于视野中的大血管，要么难以实施和分析，而且容易出现许多处理错误。通过模拟非侵入性重合检测单元，在这项工作中提出了一种替代方法。我们利用人类前臂模型的GATE模拟和血流模型，以及基于临床测量的动态放射性推注活性浓度模型。在幻像周围采用了14个固定检测器（也分别是8个检测器）的固定配置，并进行了仿真以研究信号检测参数。事实证明，锗酸铋（BGO）晶体显示出最高的计数率能力和对BTAC的模拟灵敏度，最大重合率为575 cps。血管在前臂中的重复位置允许仅使用8个检测器的半环设计。使用此配置，通过模拟从15O和18F动脉血采样确定的活性浓度，可以达到250 cps和42 cps的最大同时发生率。在8个探测器系统内部的3个不同垂直位置（Y = − 1 cm，Y = − 2 cm和Y = −3 cm）的水幻影中模拟的NECR分别为8360 cps，13,041 cps和20,476 cps 3.5 MBq。在半环配置上增加了额外的轴向检测环，使系统灵敏度提高了约10倍。最初的模拟表明，单块BGO晶体的单个半环8检测器的配置可以在临床上相关的前臂幻像中以良好的信号特性描述模拟的BTAC，并且增加的轴向检测环数量可以提高系统的灵敏度。该系统可用于BTAC的推导中，而无需实际动脉采样或依赖基于图像的技术即可用于动力学模型。