He Yibo, Gu Yushen, Yu Haojun, Wu Bing, Wang Siyang, Tan Hui, Cao Yanyan, Chen Shuguang, Sui Xiuli, Zhang Yiqiu, Shi Hongcheng
Shanghai Institute of Medical Imaging, Shanghai, 200032, China.
Department of Nuclear Medicine, Zhongshan Hospital, Fudan University, Shanghai, 200032, China.
EJNMMI Phys. 2022 Jul 8;9(1):45. doi: 10.1186/s40658-022-00474-y.
The present study aimed to explore the boundary of acquisition time and propose an optimized acquisition time range for total-body positron emission tomography (PET)/computed tomography (CT) oncological imaging using half-dose (1.85 MBq/kg) F-fluorodeoxyglucose activity based on diagnostic needs.
In this retrospective study based on a total-body PET system (uEXPLORER), an exploration cohort (October 2019-December 2019) of 46 oncology patients was first studied. The acquisition time for all patients was 15 min, and the acquired images were reconstructed and further split into 15-, 8-, 5-, 3-, 2-, and 1-min duration groups (abbreviated as G15, G8, G5, G3, G2, and G1). The image quality and lesion detectability of reconstructed PET images with different acquisition times were evaluated subjectively (5-point scale, lesion detection rate) and objectively (standardized uptake values, tumor-to-background ratio). In the same way, the initial optimized acquisition times were further validated in a cohort of 147 oncology patients (December 2019-June 2021) by using the Gs images (the images obtained using the 15- and 10-min acquisition times) as controls.
In the exploration cohort, the subjective scores for G1, G2, G3, G5, and G8 images were 2.0 ± 0.2, 2.9 ± 0.3, 3.0 ± 0.0, 3.9 ± 0.2, and 4.2 ± 0.4, respectively. Two cases in G1 were rated as 1 point. No significant difference in scores was observed between G5 and G8 (p > 0.99). In general, groups with a longer acquisition time showed lower background uptake and lesion conspicuity. Compared with G15, lesion detection rate significantly reduced to 85.3% in G1 (p < 0.05). In the validation cohort, the subjective score was 3.0 ± 0.2 for G2, 3.0 ± 0.1 for G3, 3.6 ± 0.5 for G5, 4.0 ± 0.3 for G8, and 4.4 ± 0.5 for Gs. Only the scores between G2 and G3 were not significantly different (p > 0.99). The detection rates (204 lesions) significantly reduced to 94.1-90.2% in G3 and G2 (all p < 0.05).
A 2-min acquisition time provided acceptable performance in certain groups and specific medical situations. And protocols with acquisition times ≥ 5 min could provide comparable lesion detectability as regular protocols, showing better compatibility and feasibility with clinical practice.
本研究旨在探索采集时间的边界，并根据诊断需求，基于半剂量（1.85MBq/kg）F-氟脱氧葡萄糖活性，为全身正电子发射断层扫描（PET）/计算机断层扫描（CT）肿瘤成像提出优化的采集时间范围。
在这项基于全身PET系统（uEXPLORER）的回顾性研究中，首先对46例肿瘤患者的探索队列（2019年10月至2019年12月）进行研究。所有患者的采集时间均为15分钟，采集到的图像进行重建，并进一步分为15分钟、8分钟、5分钟、3分钟、2分钟和1分钟时长组（简称为G15、G8、G5、G3、G2和G1）。采用主观（5分制，病变检出率）和客观（标准化摄取值、肿瘤与本底比值）方法评估不同采集时间重建的PET图像的图像质量和病变可探测性。同样，以Gs图像（使用15分钟和10分钟采集时间获得的图像）作为对照，在147例肿瘤患者队列（2019年12月至2021年6月）中进一步验证初始优化的采集时间。
在探索队列中，G1、G2、G3、G5和G8图像的主观评分分别为2.0±0.2、2.9±0.3、3.0±0.0、3.9±0.2和4.2±0.4。G1组中有2例评分为1分。G5和G8之间的评分无显著差异（p>0.99）。总体而言，采集时间较长的组背景摄取较低，病变清晰度较高。与G15相比，G1组的病变检出率显著降至85.3%（p<0.05）。在验证队列中，G2的主观评分为3.0±0.2，G3为3.0±0.1，G5为3.6±0.5，G8为4.0±0.3，Gs为4.4±0.5。只有G2和G3之间的评分无显著差异（p>0.99）。G3和G2组的检出率（204个病变）显著降至94.1%-90.2%（均p<0.05）。
2分钟的采集时间在某些组和特定医疗情况下可提供可接受的性能。采集时间≥5分钟的方案与常规方案相比，病变可探测性相当，在临床实践中显示出更好的兼容性和可行性。
