For the 2011 FDA approved Parkinson's Disease (PD) SPECT imaging agent I-123 labeled DaTscan, the volume of interest (VOI) is the interior portion of the brain. However imaging of the occipital lobe is also required with PD for calculation of the striatal binding ratio (SBR), a parameter of significance in early diagnosis, differentiation of PD from other disorders with similar clinical presentations, and monitoring progression. Thus we propose the usage of a combination of a multi-pinhole (MPH) collimator on one head of the SPECT system and a fan-beam on the other. The MPH would be designed to provide high resolution and sensitivity for imaging of the interior portion of the brain. The fan-beam collimator would provide lower resolution but complete sampling of the brain addressing data sufficiency and allowing a volume-of-interest to be defined over the occipital lobe for calculation of SBR's. Herein we focus on the design of the MPH component of the combined system. Combined reconstruction will be addressed in a subsequent publication. An analysis of 46 clinical DaTscan studies was performed to provide information to define the VOI, and design of a MPH collimator to image this VOI. The system spatial resolution for the MPH was set to 4.7 mm, which is comparable to that of clinical PET systems, and significantly smaller than that of fan-beam collimators employed in SPECT. With this set, we compared system sensitivities for three aperture array designs, and selected the 3 × 3 array due to it being the highest of the three. The combined sensitivity of the apertures for it was similar to that of an ultra-high resolution fan-beam (LEUHRF) collimator, but smaller than that of a high-resolution fan-beam collimator (LEHRF). On the basis of these results we propose the further exploration of this design through simulations, and the development of combined MPH and fan-beam reconstruction.

中文翻译：

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在双头 SPECT 系统上设计用于 I-123 DaTscan 成像的多针孔准直器与扇形束准直器相结合

对于 2011 年 FDA 批准的帕金森病 (PD) SPECT 显像剂 I-123 标记的 DaTscan，感兴趣的体积 (VOI) 是大脑的内部部分。然而，PD 还需要枕叶成像来计算纹状体结合率 (SBR)，这是一个在早期诊断、区分 PD 与具有相似临床表现的其他疾病以及监测进展中具有重要意义的参数。因此，我们建议在 SPECT 系统的一个头上使用多针孔 (MPH) 准直器，在另一个头上使用扇形光束。MPH 将被设计为为大脑内部的成像提供高分辨率和灵敏度。扇形光束准直器将提供较低分辨率但完整的大脑寻址数据采样，并允许在枕叶上定义感兴趣的体积以计算 SBR。在此，我们着重于组合系统的 MPH 组件的设计。联合重建将在随后的出版物中讨论。对 46 项临床 DaTscan 研究进行了分析，以提供定义 VOI 的信息，并设计 MPH 准直器以对该 VOI 成像。MPH 的系统空间分辨率设置为 4.7 mm，与临床 PET 系统的空间分辨率相当，并且明显小于 SPECT 中使用的扇形光束准直器。使用这套装置，我们比较了三种孔径阵列设计的系统灵敏度，并选择了 3 × 3 阵列，因为它是三者中最高的。它的孔径组合灵敏度与超高分辨率扇形光束 (LEUHRF) 准直器的灵敏度相似，但小于高分辨率扇形光束准直器 (LEHRF) 的灵敏度。在这些结果的基础上，我们建议通过模拟进一步探索这种设计，并开发组合 MPH 和扇形波束重建。