Department of Clinical Physiology, Nuclear Medicine and PET & Cluster for Molecular Imaging, Copenhagen University Hospital - Rigshospitalet & Department of Biomedical Sciences, University of Copenhagen, Copenhagen, Denmark.
ENETS Neuroendocrine Tumor Center of Excellence, Copenhagen University Hospital - Rigshospitalet, Copenhagen, Denmark.
Mol Imaging Biol. 2022 Aug;24(4):600-611. doi: 10.1007/s11307-022-01706-4. Epub 2022 Feb 15.
Patients with neuroendocrine neoplasms (NEN) engage in lifelong follow-up with frequent somatostatin receptor PET, e.g. [Cu]Cu-DOTATATE PET, and continued measures to reduce radiation exposures should be in pursued in accordance with the as-low-as-reasonably-achievable (ALARA) principle. We therefore aimed to determine the lowest achievable [Cu]Cu-DOTATATE dose while maintaining image quality and lesion detection rate.
We included scans from 38 patients with NEN referred to routine [Cu]Cu-DOTATATE PET/CT. Using reconstruction of under-sampled PET list-mode data, we simulated [Cu]Cu-DOTATATE activity dose-reduced PET equivalents with median [range] 142 MBq [127;157], 95 MBq [85;105], and 48 MBq [42;52], corresponding to 75% (PET), 50% (PET), and 25% (PET) of the full-dose 191 MBq [169;209] (PET). Three blinded readers independently assessed image quality (scores 1-5), lesion confidence (scores 0-2), and counted lesions grouped by organs and regions. Number of lesions, proportions of patients with diagnostic image quality (reader-median image quality ≥ 4), diagnostic lesion confidence (reader-median lesion confidence ≥ 1), and per-patient sensitivities and specificities for organ-specific disease on PET were compared with PET.
The median [Cu]Cu-DOTATATE activity dose could be reduced from 191 to 142 MBq without decline in diagnostic image quality (P = 0.62), diagnostic lesion confidence (P = 1.0), or number of lesions detected in major organs or regions (P = 0.19-0.71). Sensitivity and specificity for detection of liver disease were 100% (26/26 patients) and 100% (12/12), respectively, for both PET and PET. Overall sensitivity for detection of NEN was 100% (26/26) for both PET and PET, and overall specificities were 92% (11/12) and 100% (12/12) for PET and PET, respectively. Following dose-blinded post hoc review, the PET specificity was adjusted to 100% (12/12).
The [Cu]Cu-DOTATATE activity dose can be reduced from 191 MBq to at least 142 MBq without losing image quality or lesion detection ability and further reduced to 95 MBq without loss of clinically relevant information.
神经内分泌肿瘤（NEN）患者需要进行终身随访，包括频繁的生长抑素受体 PET 检查，例如 [Cu]Cu-DOTATATE PET，并且应根据尽可能低的合理可达（ALARA）原则继续采取措施降低辐射暴露。因此，我们旨在确定在保持图像质量和病变检出率的情况下，实现最低可达到的 [Cu]Cu-DOTATATE 剂量。
我们纳入了 38 例接受常规 [Cu]Cu-DOTATATE PET/CT 检查的 NEN 患者的扫描结果。使用欠采样 PET 列表模式数据的重建，我们模拟了 142MBq[127；157]、95MBq[85；105]和 48MBq[42；52]中位数（范围）的 [Cu]Cu-DOTATATE 活性剂量减少的 PET 等效物，分别对应于全剂量 191MBq[169；209]（PET）的 75%（PET）、50%（PET）和 25%（PET）。三位盲法读者独立评估了图像质量（评分 1-5）、病变置信度（评分 0-2），并按器官和区域分组计数病变。比较了与 PET 相比，每个患者的病变数量、具有诊断性图像质量（读者中位数图像质量≥4）的患者比例、具有诊断性病变置信度（读者中位数病变置信度≥1）的患者比例，以及针对特定器官疾病的每例患者的敏感性和特异性。
191MBq 的 [Cu]Cu-DOTATATE 活性剂量可降低至 142MBq，而不会降低诊断性图像质量（P=0.62）、诊断性病变置信度（P=1.0）或主要器官或区域中检出的病变数量（P=0.19-0.71）。PET 和 PET 检测肝脏疾病的灵敏度和特异性均为 100%（26/26 例患者）和 100%（12/12 例）。PET 和 PET 检测 NEN 的总体灵敏度均为 100%（26/26 例），PET 和 PET 的总体特异性分别为 92%（11/12 例）和 100%（12/12 例）。在剂量盲法事后审查后，将 PET 的特异性调整为 100%（12/12）。
[Cu]Cu-DOTATATE 活性剂量可从 191MBq 降低至至少 142MBq，而不会降低图像质量或病变检出能力，进一步降低至 95MBq 不会丢失临床相关信息。
