Positron emission tomography with additional γ-ray detectors for multipletracer imaging
Positron emission tomography with additional γ-ray detectors for multipletracer imaging
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DOI：
10.1002/mp.12149
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发表时间：
2017-06-01
期刊：
影响因子：
3.8
通讯作者：
Enomoto, Shuichi
中科院分区：
文献类型：
--
作者：
Fukuchi, Tomonori;Okauchi, Takashi;Enomoto, Shuichi
目的：正电子发射断层扫描（PET）是一种有用的成像方式，它可以量化人体和动物体内放射性标记示踪剂的生理分布。然而，该技术不适合于多示踪剂成像，因为用于PET成像的湮灭光子具有固定的能量，而与放射性核素示踪剂的选择无关。本研究开发了一种多同位素PET（MI-PET）系统，并评估其成像performance.Methods：我们的MI-PET系统是由一个PET系统和额外的C射线探测器。PET系统由像素化的原硅酸钆（GSO）闪烁探测器组成，具有直径为95 mm的环形几何结构，轴向视场为37.5 mm。附加探测器为8个氧化铋锗（BGO）闪烁探测器，每个探测器为50 9 50 9 30 mm 3，排列成两个环，安装在直径为92 mm的PET环的每一侧。该系统可以使用附加的c射线探测器来区分不同的示踪剂，以观察瞬发c射线，其在正电子发射之后发射并且具有每个放射性核素固有的能量。我们的系统可以同时获得双（两个湮灭光子）和三重（两个湮灭光子和一个即时c射线）符合事件。使用正电子-c发射器Na-22测量系统用于检测即时去激发c-射线的效率。双放射性核素（F-18和Na-22）成像的杆体模和小鼠进行了演示所开发的系统的性能。我们的系统的基本性能通过重建两个图像来评估，一个包含两个示踪剂，另一个只包含第二个示踪剂，从列表模式数据集，这些数据集根据提示c射线的存在或不存在进行分类。从Na-22发射的1275 keV c射线的最大探测效率在扫描仪中心约为7%，在视场边缘检测效率最低为5.1%。点源和杆体模的双放射性核素成像显示，我们的系统保持PET的固有空间分辨率和定量性质的第二示踪剂。我们还成功地从含有F-18-氟脱氧葡萄糖和Na-22溶解在水中的小鼠中获得了同时的双重和三重符合事件。从生理学和药代动力学的观点来看，我们的MI-PET获得的小鼠中的双示踪剂分布是合理的。结论：这项研究表明了使用PET与额外的C-射线探测器的多示踪剂成像的可行性。这种方法有望使定量多示踪剂图像的重建，并可能是非常有用的分析多分子动力学。(C)2017年美国医学物理学家协会
Purpose: Positron emission tomography (PET) is a useful imaging modality that quantifies the physiological distributions of radiolabeled tracers in vivo in humans and animals. However, this technique is unsuitable for multiple-tracer imaging because the annihilation photons used for PET imaging have a fixed energy regardless of the selection of the radionuclide tracer. This study developed a multiisotope PET (MI-PET) system and evaluated its imaging performance.Methods: Our MI-PET system is composed of a PET system and additional c-ray detectors. The PET system consists of pixelized gadolinium orthosilicate (GSO) scintillation detectors and has a ring geometry that is 95 mm in diameter with an axial field of view of 37.5 mm. The additional detectors are eight bismuth germanium oxide (BGO) scintillation detectors, each of which is 50 9 50 9 30 mm 3, arranged into two rings mounted on each side of the PET ring with a 92-mminner diameter. This system can distinguish between different tracers using the additional c-ray detectors to observe prompt c-rays, which are emitted after positron emission and have an energy intrinsic to each radionuclide. Our system can simultaneously acquire double-(two annihilation photons) and triple-(two annihilation photons and a prompt c-ray) coincidence events. The system's efficiency for detecting prompt de-excitation c-rays was measured using a positron-c emitter, Na-22. Dual-radionuclide (F-18 and Na-22) imaging of a rod phantom and a mouse was performed to demonstrate the performance of the developed system. Our system's basic performance was evaluated by reconstructing two images, one containing both tracers and the other containing just the second tracer, from list-mode data sets that were categorized by the presence or absence of the prompt c-ray.Results: The maximum detection efficiency for 1275 keV c-rays emitted from Na-22 was approximately 7% at the scanner's center, and the minimum detection efficiency was 5.1% at the edge of the field of view. Dual-radionuclide imaging of the point sources and rod phantom revealed that our system maintained PET's intrinsic spatial resolution and quantitative nature for the second tracer. We also successfully acquired simultaneous double-and triple-coincidence events from a mouse containing F-18-fluoro-deoxyglucose and Na-22 dissolved in water. The dual-tracer distributions in the mouse obtained by our MI-PETwere reasonable from the viewpoints of physiology and pharmacokinetics.Conclusions: This study demonstrates the feasibility of multiple-tracer imaging using PET with additional c-ray detectors. This method holds promise for enabling the reconstruction of quantitative multiple-tracer images and could be very useful for analyzing multiple-molecular dynamics. (C) 2017 American Association of Physicists in Medicine