Department of Radiology, University of Pennsylvania, Philadelphia, PA, United States of America.
Phys Med Biol. 2023 May 11;68(10). doi: 10.1088/1361-6560/accf5d.
. Current commercial positron emission tomography (PET) scanners have excellent performance and diagnostic image quality primarily due to improvements in scanner sensitivity and time-of-flight (TOF) resolution. Recent years have seen the development of total-body PET scanners with longer axial field-of-view (AFOV) that increase sensitivity for single organ imaging, and also image more of the patient in a single bed position thereby enabling multi-organ dynamic imaging. While studies have shown significant capabilities of these systems, cost will be a major factor in their widespread adoption in the clinic. Here we evaluate alternative designs that achieve many advantages of long AFOV PET while utilizing cost-effective detector hardware.. We utilize Monte Carlo simulations and clinically relevant lesion detectability metric to study the impact of scintillator type lutetium oxyorthosilicate or bismuth germanate (LSO or BGO), scintillator thickness (10-20 mm), and TOF resolution on resultant image quality in a 72 cm long scanner. Detector TOF resolution was varied based on current scanner performance, as well as expected future performance from detector designs that currently hold most promise for scaling into a scanner.. Results indicate that BGO is competitive with LSO (both 20 mm thick) if we assume that it uses TOF (e.g. Cerenkov timing with 450 ps fwhm and Lorentzian distribution) and the LSO scanner has TOF resolution similar to the latest PMT-based scanners (∼500-650 ps). Alternatively, a system using 10 mm thick LSO with 150 ps TOF resolution can also provide similar performance. Both these alternative systems can provide cost savings (25%-33%) relative to a scanner using 20 mm LSO with ∼50% of effective sensitivity, but still 500%-700% higher than a conventional AFOV scanner.. Our results have relevance to the development of long AFOV PET, where reduced cost of these alternative designs can provide wider accessibility for use in situations requiring imaging of multiple organs simultaneously.
. 目前的商用正电子发射断层扫描（PET）扫描仪具有出色的性能和诊断图像质量，这主要归功于扫描仪灵敏度和飞行时间（TOF）分辨率的提高。近年来，开发了具有更长轴向视野（AFOV）的全身 PET 扫描仪，这提高了单个器官成像的灵敏度，并且还可以在单个床位位置对更多的患者进行成像，从而实现多器官动态成像。虽然研究表明这些系统具有显著的能力，但成本将是其在临床广泛采用的主要因素。在这里，我们评估了替代设计，这些设计在利用成本效益高的探测器硬件的同时，实现了长 AFOV PET 的许多优势。. 我们利用蒙特卡罗模拟和临床相关的病变检测度量标准来研究闪烁体类型硅酸镥（LSO）或锗酸铋（BGO）、闪烁体厚度（10-20 毫米）和 TOF 分辨率对 72 厘米长扫描仪中图像质量的影响。探测器的 TOF 分辨率是根据当前的扫描仪性能以及当前最有希望扩展到扫描仪的探测器设计的预期未来性能来变化的。. 结果表明，如果我们假设 BGO 使用 TOF（例如，具有 450 ps 半高全宽和洛伦兹分布的切伦科夫时间），并且 LSO 扫描仪的 TOF 分辨率与最新的基于 PMT 的扫描仪（约 500-650 ps）相似，那么 BGO 与 LSO（两者均为 20 毫米厚）具有竞争力。或者，也可以使用具有 150 ps TOF 分辨率的 10 毫米厚 LSO 的系统提供类似的性能。这两种替代系统都可以节省成本（25%-33%），与使用 20 毫米 LSO 且有效灵敏度约为 50%的扫描仪相比，但仍比传统的 AFOV 扫描仪高 500%-700%。. 我们的研究结果与长 AFOV PET 的发展有关，在这些替代设计的成本降低的情况下，可以更广泛地获得这些设计，以满足同时对多个器官进行成像的需求。
