Aim: High-sensitivity hybrid positron emission tomography (PET) imaging using advanced whole-body (WB) or total-body PET/computed tomography (CT) systems permits reducing injected tracer activity while preserving diagnostic quality. Such approaches are promising for healthy control studies or exploring inter-organ communication in systemic diseases. This study assessed test/retest variations in the fluoro-2-deoxy-D-glucose (FDG) uptake in key organs from low-dose (LD) and standard-dose (STD) [18F]FDG-PET/CT imaging protocols in healthy controls and lung cancer patients.Methods: A total of 19 healthy controls (19–62 years, 46–104 kg, 10 M/9 F) and 7 lung cancer patients (47–77 years, 50–88 kg, 4 M/3 F) underwent [18F]FDG-PET/CT imaging. All subjects were first injected (“test,” LD) with 28 ± 2 MBq FDG and underwent a dynamic (0–67 min post-injection) WB imaging protocol with LD-CT. Then, 90 min post-LD injection, the subjects were repositioned and injected with 275 ± 16 MBq FDG (“retest,” STD). Second LD-CT and STD-CT scans were acquired for healthy controls and patients, respectively. Static images (55–67 min post-injection) were considered for subsequent analysis. The CT images were used to automatically segment the target volumes of interest. Standardized uptake values normalized to the body weight (SUVBW) were extracted for each volume of interest. The mean SUVBW were compared for both LD/STD conditions with paired t-tests. In patients, FDG-avid lesions were manually delineated on LD and STD static images. Effective dose levels were estimated from both the CT and PET acquisitions.Results: Organ-based mean SUVBW were similar between the LD and STD (mean %difference ≤5%) in both healthy controls and cancer patients, except in the heart. Intra-control test/retest variability was significant in the brain, heart, and skeletal muscle (p < 0.05). While 17 lesions were delineated on the STD images of the patients, only 10/17 lesions were identified on the LD images due to increased image noise. Lesion-based mean SUVBW were similar between LD and STD acquisitions (p = 0.49, %difference = 10%). In patients, the effective doses were (1.9 ± 0.2) mSv (LD-CT), (16.6 ± 5.4) mSv (STD-CT), (0.5 ± 0.1) mSv (LD-PET), and (4.6 ± 0.3) mSv (STD-PET).Conclusion: LD and STD [18F]FDG injections in healthy controls and lung cancer patients yielded comparable mean SUVBW, except in the heart. Dose levels may be reduced for [18F]FDG-PET imaging without a loss in mean SUVBW accuracy, promoting LD-PET/CT protocols for studying multi-organ metabolic patterns. In oncology patients, this approach may be hindered by a lower diagnostic quality in the presence of significant noise.

中文翻译：

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低剂量和标准剂量全身 [18F]FDG-PET/CT 成像：对健康对照和肺癌患者的影响

目的：使用先进的全身 (WB) 或全身 PET/计算机断层扫描 (CT) 系统进行高灵敏度混合正电子发射断层扫描 (PET) 成像，可以减少注射的示踪剂活性，同时保持诊断质量。这些方法对于健康对照研究或探索系统性疾病中的器官间通讯很有希望。本研究评估了低剂量 (LD) 和标准剂量 (STD) [18F]FDG-PET/CT 成像方案中关键器官中氟-2-脱氧-D-葡萄糖 (FDG) 摄取的测试/再测试变化。方法：共有 19 名健康对照者（19-62 岁，46-104 kg，10 M/9 F）和 7 名肺癌患者（47-77 岁，50-88 kg，4 M） /3 F) 进行了 [18F]FDG-PET/CT 成像。所有受试者首先注射（“测试”，LD）28 ± 2 MBq FDG，并使用 LD-CT 进行动态（注射后 0-67 分钟）WB 成像方案。然后，LD 注射后 90 分钟，受试者重新定位并注射 275 ± 16 MBq FDG（“重新测试”，STD）。分别对健康对照和患者进行第二次 LD-CT 和 STD-CT 扫描。静态图像（注射后 55-67 分钟）被考虑用于后续分析。 CT 图像用于自动分割感兴趣的目标体积。根据体重归一化的标准化摄取值（SUV体重）针对每个感兴趣的体积进行提取。平均SUV体重通过配对 t 检验对 LD/STD 条件进行比较。在患者中，在 LD 和 STD 静态图像上手动描绘出富含 FDG 的病灶。根据 CT 和 PET 采集数据估算有效剂量水平。结果：基于器官的平均 SUV体重健康对照组和癌症患者的 LD 和 STD 之间相似（平均％差异≤5％），心脏除外。对照内测试/再测试变异性在大脑、心脏和骨骼肌中显着（p< 0.05）。虽然患者的 STD 图像上描绘出 17 个病变，但由于图像噪声增加，LD 图像上仅识别出 10/17 个病变。基于病变的平均 SUV体重LD 和 STD 采集之间相似（p= 0.49，%差异 = 10%）。在患者中，有效剂量为（1.9±0.2）mSv（LD-CT）、（16.6±5.4）mSv（STD-CT）、（0.5±0.1）mSv（LD-PET）和（4.6±0.3）mSv (STD-PET)。结论：健康对照和肺癌患者注射 LD 和 STD [18F]FDG 产生的平均 SUV 相当体重，除了心里。 [18F]FDG-PET 成像的剂量水平可以降低，而平均 SUV 不会损失体重准确性，促进 LD-PET/CT 方案研究多器官代谢模式。在肿瘤患者中，这种方法可能会因存在显着噪音的情况下诊断质量较低而受到阻碍。