Department of Nuclear Medicine. Inselspital, Bern University Hospital, University of Bern, Freiburgstr. 18, 3010, Bern, Switzerland.
Ann Nucl Med. 2021 Apr;35(4):485-492. doi: 10.1007/s12149-021-01588-6. Epub 2021 Feb 7.
To establish the feasibility of shorter acquisition times (and by analogy, applied activity) on tumour detection and lesion contrast in digital PET/CT.
Twenty-one randomly selected patients who underwent oncological [F]-FDG PET/CT on a digital PET/CT were retrospectively evaluated. Scan data were anonymously obtained and reconstructed in list-mode acquisition for a standard 2 min/bed position (bp), 1 min/bp and 30 s/bp (100%, 50% and 25% time or applied activity, respectively). Scans were randomized and read by two nuclear medicine physicians in a consensus read. Readers were blind to clinical details. Scans were evaluated for the number of pathological lesions detected. Measured uptake for lesions was evaluated by maximum and mean standardized uptake value (SUVmax and SUVmean, respectively) and tumour-to-backround ratio (TBR) were compared. Agreement between the three acquisitions was compared by Krippendorf's alpha.
Overall n = 100 lesions were identified in the 2 min and 1 min/bp acquisitions and n = 98 lesions in the 30 s/bp acquisitions. Agreement between the three acquisitions with respect to lesion number and tumour-to-background ratio showed almost perfect agreement (K's α = 0.999). SUVmax, SUVmean and TBR likewise showed > 98% agreement, with longer acquisitions being associated with slightly higher mean TBR (2 min/bp 7.94 ± 4.41 versus 30 s/bp 7.84 ± 4.22, p < 0.05).
Shorter acquisition times have traditionally been associated with reduced lesion detectability or the requirement for larger amounts of radiotracer activity. These data confirm that this is not the case for new-generation digital PET scanners, where the known higher sensitivity results in clinically adequate images for shorter acquisitions. Only a small variation in the semi-quantitative parameters SUVmax, SUVmean and TBR was seen, confirming that either reduction of acquisition time or (by analogy) applied activity can be reduced as much as 75% in digital PET/CT without apparent clinical detriment.
探讨在数字 PET/CT 中，较短的采集时间（以及相应的应用活度）在肿瘤检测和病灶对比度方面是否具有可行性。
回顾性分析了 21 例在数字 PET/CT 上接受肿瘤[F]-FDG PET/CT 检查的随机患者。匿名获取扫描数据，并以列表模式采集进行重建，采集时间分别为标准的 2 分钟/床位（bp）、1 分钟/bp 和 30 秒/bp（分别为 100%、50%和 25%的时间或应用活度）。扫描随机分配，由两名核医学医师进行共识阅读。阅读者对临床细节不知情。评估了检测到的病理性病变数量。通过最大标准化摄取值（SUVmax）和平均标准化摄取值（SUVmean）评估病变的摄取情况，并比较肿瘤与背景的比值（TBR）。通过 Krippendorf's alpha 比较三种采集方式之间的一致性。
在 2 分钟和 1 分钟/bp 采集时共发现 100 个病变，在 30 秒/bp 采集时共发现 98 个病变。三种采集方式在病变数量和肿瘤与背景比值方面的一致性几乎达到完美（K 的α=0.999）。SUVmax、SUVmean 和 TBR 的一致性也超过 98%，较长的采集时间与稍高的平均 TBR 相关（2 分钟/bp 7.94±4.41 与 30 秒/bp 7.84±4.22，p<0.05）。
传统上，较短的采集时间与降低病变检出率或需要更大剂量的放射性示踪剂活度有关。这些数据证实，对于新一代数字 PET 扫描仪而言，情况并非如此，因为已知的更高灵敏度可提供适合较短采集时间的临床充分图像。SUVmax、SUVmean 和 TBR 的半定量参数仅略有变化，这证实了在数字 PET/CT 中，采集时间或（类比）应用活度可减少 75%，而不会出现明显的临床损害。
