Wu Ha, Liu Guobing, Yu Haojun, Zheng Zhe, He Yibo, Shi Hongcheng
Department of Nuclear Medicine, Zhongshan Hospital, Fudan University, Shanghai, 200032, China.
Institute of Nuclear Medicine, Fudan University, Shanghai, 200032, China.
Br J Radiol. 2025 Jan 1;98(1165):136-142. doi: 10.1093/bjr/tqae208.
To investigate the feasibility of paediatric 18F-FDG total-body PET/CT imaging with an ultra-low activity and explore an optimized acquisition time range.
A total of 38 paediatric patients were prospectively enrolled and underwent dynamic total-body PET/CT imaging using ultra-low 18F-FDG activity (0.37 MBq/kg). The 60-minute list-mode raw data were acquired and then reconstructed as static PET images by using 50-51, 50-52, 50-53, 50-54, 50-55, 50-58, 50-60, and 45-60 minutes data, which were noted as G1, G2, G3, G4, G5, G8, G10, and G15, respectively. Image qualities were subjectively evaluated using the Likert scale and were objectively evaluated by the quantitative metrics including standard uptake value (SUV), signal-to-noise ratio (SNR), target-to-background ratio (TBR), and contrast-to-noise ratio (CNR).
The injected activity of FDG was 13.38 ± 5.68 MBq (4.40-28.16 MBq) and produced 0.58 ± 0.19 mSv (0.29-1.04 mSv) of effective dose. The inter-reader agreement of subjective image quality was excellent (kappa = 0.878; 95% CI, 0.845-0.910). The average scores of image quality for G1-G15 were 1.10 ± 0.20, 2.03 ± 0.26, 2.66 ± 0.35, 3.00 ± 0.27, 3.32 ± 0.34, 4.25 ± 0.30, 4.49 ± 0.36, and 4.70 ± 0.37, respectively. All image scores are above 3, and all lesions are detectable starting from G8. SNRs of backgrounds, TBRs, and CNRs were significant differences from the control group before G8 (all P < 0.05).
The image quality of the 8 min acquisition for paediatric 18F-FDG total-body PET/CT with an ultra-low activity could meet the diagnostic requirements.
This study confirms the feasibility of ultra-low dose PET imaging in children, and its methods and findings may guide clinical practice. Paediatric patients will benefit from reduced radiation doses.
探讨超低活度小儿18F-FDG全身PET/CT成像的可行性，并探索优化的采集时间范围。
前瞻性纳入38例小儿患者，采用超低18F-FDG活度（0.37 MBq/kg）进行动态全身PET/CT成像。采集60分钟的列表模式原始数据，然后分别使用50 - 51、50 - 52、50 - 53、50 - 54、50 - 55、50 - 58、50 - 60以及45 - 60分钟的数据重建为静态PET图像，分别记为G1、G2、G3、G4、G5、G8、G10和G15。采用Likert量表对图像质量进行主观评估，并通过包括标准摄取值（SUV）、信噪比（SNR）、靶本比（TBR）和对比噪声比（CNR）在内的定量指标进行客观评估。
FDG的注射活度为13.38±5.68 MBq（4.40 - 28.16 MBq），有效剂量为0.58±0.19 mSv（0.29 - 1.04 mSv）。阅片者间主观图像质量的一致性极佳（kappa = 0.878；95%CI，0.845 - 0.910）。G1 - G15的图像质量平均得分分别为1.10±0.20、2.03±0.26、2.66±0.35、3.00±0.27、3.32±0.34、4.25±0.30、4.49±0.36和4.70±0.37。所有图像得分均高于3分，从G8开始所有病变均可检测到。在G8之前，背景的SNR、TBR和CNR与对照组有显著差异（均P < 0.05）。
超低活度小儿18F-FDG全身PET/CT 8分钟采集的图像质量可满足诊断要求。
本研究证实了超低剂量PET成像在儿童中的可行性，其方法和结果可能指导临床实践。小儿患者将从降低的辐射剂量中受益。
