Department of Nuclear Medicine, Zhongshan Hospital, Fudan University.
Nuclear Medicine Institute of Fudan University.
Nucl Med Commun. 2022 Aug 1;43(8):928-936. doi: 10.1097/MNM.0000000000001589. Epub 2022 May 30.
The purpose of this study was to investigate image quality and lesion detectability of half-dose (1.85 MBq/kg) 18 F-fluorodeoxyglucose (FDG) total-body positron emission tomography/computed tomography (PET/CT) for colorectal cancer, full-dose (3.7 MBq/kg) 18 F-FDG serving as a reference.
Fifty patients confirmed to have colorectal cancer who underwent total-body PET/CT with half-dose 18 F-FDG were included. Another 50 colorectal cancer patients with 3.70 MBq/kg 18 F-FDG activity were selected for the full-dose group. PET images in the half-dose group were scanned for 15 min and split into 1-, 2-, 3-, 4- and 10-min duration groups, denoted G1, G2, G3, G4 and G10, respectively. In the full-dose group, PET scanning was performed for 5 min, reconstructed with the first 0.5, 1, 2 and 5 min intervals, defined as G0.5', G1', G2' and G5', respectively. Subjective image quality was assessed with 5-point Likert scales. Objective image quality parameters included maximum standardized uptake values (SUV max) , mean standardized uptake values (SUV mean )and signal-to-noise ratio (SNR) of the liver, blood pool and muscle and SUV max and tumor-to-background ratio (TBR) of lesions.
In the two groups, the G3 and G2' images met clinical diagnosis requirements in terms of subjective image quality, with scores ≥3. There were no differences in terms of subjective and objective image quality between the groups (G1 and G0.5', G2 and G1', G4 and G2' and G10 and G5'). In the half-dose group, 56 colorectal lesions in 50 patients confirmed by surgical pathology were clearly visible in all groups. The number of FDG-avid lymph nodes was 37 in G1, 38 in G2 and 39 in the remaining half-dose groups. The number of missed metastatic liver lesions was 1 both in G1 and G2.
Total-body PET/CT with half-dose was feasible for diagnosing and staging colorectal cancer compared with full-dose 18 F-FDG PET/CT. Moreover, for half-dose total-body PET/CT, a 3-min scan duration could maintain image quality and lesion detectability.
本研究旨在探讨全身 18 F-氟代脱氧葡萄糖（FDG）正电子发射断层扫描/计算机断层扫描（PET/CT）半剂量（1.85MBq/kg）在结直肠癌中的应用价值，以全剂量（3.7MBq/kg）18 F-FDG 作为参考。
本研究纳入 50 例经病理证实的结直肠癌患者，行全身半剂量 18 F-FDG PET/CT 检查。另选择 50 例结直肠癌患者，行全剂量 18 F-FDG PET/CT 检查。半剂量组的 PET 图像扫描 15min，分为 1、2、3、4 和 10min 持续时间组，分别记为 G1、G2、G3、G4 和 G10。全剂量组 PET 扫描 5min，重建第 0.5、1、2 和 5min 间隔的图像，分别记为 G0.5'、G1'、G2'和 G5'。采用 5 分制 Likert 量表评估主观图像质量。客观图像质量参数包括肝脏、血池和肌肉的最大标准化摄取值（SUV max）、平均标准化摄取值（SUV mean）和信噪比（SNR），以及病灶的 SUV max 和肿瘤与背景比值（TBR）。
两组中，G3 和 G2'的主观图像质量评分均≥3，满足临床诊断要求。两组间的主观和客观图像质量无差异（G1 和 G0.5'、G2 和 G1'、G4 和 G2'和 G10 和 G5'）。半剂量组 50 例患者中，56 例经手术病理证实的结直肠病变在所有组中均清晰可见。G1 组有 37 个 FDG 阳性淋巴结，G2 组有 38 个，其余半剂量组有 39 个。G1 和 G2 组均有 1 例肝转移瘤漏诊。
与全剂量 18 F-FDG PET/CT 相比，全身半剂量 PET/CT 诊断和分期结直肠癌是可行的。此外，对于全身半剂量 PET/CT，3min 的扫描时间可以保持图像质量和病灶检出率。
