Honoré d'Este Sabrina, Andersen Flemming Littrup, Schulze Christina, Saxtoft Eunice, Fischer Barbara Malene, Andersen Kim Francis
Department of Clinical Physiology and Nuclear Medicine, Rigshospitalet, Copenhagen University Hospital, Copenhagen, Denmark.
Department of Clinical Medicine, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark.
Front Nucl Med. 2024 Jun 13;4:1398773. doi: 10.3389/fnume.2024.1398773. eCollection 2024.
Pediatric patients have an increased risk of radiation-induced malignancies due to their ongoing development and long remaining life span. Thus, optimization of PET protocols is an important task in pediatric nuclear medicine. Long axial field-of-view (LAFOV) PET/CT has shown a significant increase in sensitivity, which provides an ideal opportunity for reduction of injected tracer activity in the pediatric population. In this study we aim to evaluate the clinical performance of a 2-[F]FDG-tracer reduction from 3 MBq/kg to 1.5 MBq/kg on the Biograph Vision Quadra LAFOV PET/CT.
The first 50 pediatric patients referred for clinical whole-body PET/CT with 1.5 MBq/kg 2-[F]FDG, were included. A standard pediatric protocol was applied. Five reconstructions were created with various time, filter and iteration settings. Image noise was computed as coefficient-of-variance (COV = SD/mean standardized-uptake-value) calculated from a spherical 20-50 mm (diameter) liver volume-of-interest. Sets of reconstructions were reviewed by one nuclear medicine physicians, who reported image lesions on a pre-defined list of sites. Paired comparison analysis was performed with significance at (Bonferroni corrected).
All reconstructions, except one, achieved a COV (0.08-0.15) equal to or lower than current clinical acceptable values (COV ≤ 0.15). Image noise significantly improved with increasing acquisition time, lowering iterations (i) from 6i to 4i (both with five subsets) and when applying a 2 mm Gauss filter (). Significant difference in lesion detection was seen from 150s to 300s and from 150s to 600s (). 99% of all lesions rated as malignant could be found on the 150s reconstruction, while 100% was found on the 300s, when compared to the 600s reconstruction.
Injected activity and scan time can be reduced to 1.5 MBq/kg 2-[F]FDG with 5 min acquisition time on LAFOV PET/CT, while maintaining clinical performance in the pediatric population. These results can help limit radiation exposure to patients and personnel as well as shorten total scan time, which can help increase patient comfort, lessen the need for sedation and provide individually tailored scans.
由于小儿患者仍在持续发育且预期寿命较长，他们发生辐射诱发恶性肿瘤的风险更高。因此，优化正电子发射断层扫描（PET）方案是儿科核医学的一项重要任务。长轴视野（LAFOV）PET/CT的灵敏度显著提高，这为降低儿科患者群体中注射示踪剂的活度提供了理想契机。在本研究中，我们旨在评估在Biograph Vision Quadra LAFOV PET/CT上将2-[F]氟代脱氧葡萄糖（FDG）示踪剂活度从3 MBq/kg降至1.5 MBq/kg的临床性能。
纳入了首批50例被转诊进行临床全身PET/CT检查、注射1.5 MBq/kg 2-[F]FDG的儿科患者。采用标准儿科方案。使用不同的时间、滤波和迭代设置创建了五种重建图像。图像噪声通过从直径为20 - 50 mm的球形肝脏感兴趣区计算得到的变异系数（COV = 标准差/平均标准化摄取值）来计算。一组核医学医师对重建图像进行了评估，他们在预定义的部位列表上报告图像病变情况。采用配对比较分析，显著性水平为（经Bonferroni校正）。
除一种重建图像外，所有重建图像的COV（0.08 - 0.15）均等于或低于当前临床可接受值（COV≤0.15）。随着采集时间增加、将迭代次数（i）从6次降至4次（均为五个子集）以及应用2 mm高斯滤波器时，图像噪声显著改善（）。在150秒至300秒以及150秒至600秒之间，病变检测存在显著差异（）。与600秒重建图像相比，99%被判定为恶性的病变在150秒重建图像上能够被发现，而在300秒重建图像上则为100%。
在LAFOV PET/CT上，注射活度和扫描时间可降至1.5 MBq/kg 2-[F]FDG且采集时间为5分钟，同时保持儿科患者群体的临床性能。这些结果有助于限制患者和工作人员所受的辐射暴露，以及缩短总扫描时间，这有助于提高患者舒适度、减少镇静需求并提供个性化定制扫描。
