Department of Radiological Sciences, College of Applied Sciences, King Saud University P. O.Box 10219, Riyadh 11433, Saudi Arabia.
Department of Physics, College of Science, Imam Muhammad Ibn Saud Islamic University, Riyadh 11461, Saudi Arabia.
Curr Med Imaging. 2021;17(2):296-305. doi: 10.2174/1573405616666201012154548.
The purpose of the present work was to evaluate the imaging characteristics of Zr-PET in comparison with those obtained using fluorine-18 Fluorodeoxyglucose (18FFDG) PET (a gold standard tracer in PET imaging) using a small-animal NanoScan PET/CT scanner.
The system's spatial resolution, sensitivity, uniformity, and image quality were measured on a Nano Scan small-animal PET/CT scanner according to the NEMA NU4-2008 protocols. For reconstruction images, we used 2D and 3D reconstruction algorithms. The reconstruction methods included filter back projection (FBP), the ordered subsets expectation maximization (OSEM) algorithm, and the 3D Tera-Tomo algorithm, which are developed for the NanoScan small-animal PET/CT scanner.
The results obtained showed a significant difference in the spatial resolution for Zr as compared to 22Na and 18F when using a 2D reconstruction algorithm. The spatial resolution values were much enhanced by using the 3D Tera-Tomo reconstruction for each isotope, the Full width at half maximum (FWHM) values was less than 1 for all isotopes at the center of the field of view (FOV). This difference in spatial resolution is dependent on the positron range, energy, and the reconstruction method.
The long half-life of Zr makes it an ideal positron emitter for performing immuno- PET, which is matched with the biological half-life of intact mAbs.Zr can also give several advantages over other long half-life positron emitters in relation to the overall imaging performance because of its relatively short positron range and simpler decay scheme. The values of Zr sensitivity that were obtained in the present study were less than those of previous studies.
本研究旨在通过使用小动物 NanoScan PET/CT 扫描仪，评估 Zr-PET 的成像特征，并与氟-18 氟代脱氧葡萄糖（18FFDG）PET（PET 成像中的金标准示踪剂）的成像特征进行比较。
根据 NEMA NU4-2008 协议，在 NanoScan 小动物 PET/CT 扫描仪上测量系统的空间分辨率、灵敏度、均匀性和图像质量。对于重建图像，我们使用 2D 和 3D 重建算法。重建方法包括滤波反投影（FBP）、有序子集期望最大化（OSEM）算法和专为 NanoScan 小动物 PET/CT 扫描仪开发的 3D Tera-Tomo 算法。
使用 2D 重建算法时，与 22Na 和 18F 相比，Zr 的空间分辨率存在显著差异。使用每个同位素的 3D Tera-Tomo 重建，空间分辨率值得到了显著提高，视野（FOV）中心的半峰全宽（FWHM）值均小于 1。这种空间分辨率的差异取决于正电子射程、能量和重建方法。
Zr 的长半衰期使其成为进行免疫 PET 的理想正电子发射体，与完整单抗的生物学半衰期相匹配。与其他长半衰期正电子发射体相比，Zr 还因为其相对较短的正电子射程和更简单的衰变方案，在整体成像性能方面具有一些优势。本研究中获得的 Zr 灵敏度值低于之前的研究。
